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+name: Create Release
+
+on:
+  workflow_dispatch:
+    inputs:
+      version:
+        description: 'Release version (e.g., 1.1.5)'
+        required: true
+        type: string
+
+permissions:
+  contents: write
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Update manifest.json
+        run: |
+          sed -i 's/"version": ".*"/"version": "${{ github.event.inputs.version }}"/' custom_components/boiler_aux_heater_3phase/manifest.json
+
+      - name: Commit manifest change
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+          git add custom_components/boiler_aux_heater_3phase/manifest.json
+          git commit -m "Bump version to ${{ github.event.inputs.version }}"
+          git push
+
+      - name: Create tag
+        run: |
+          git tag v${{ github.event.inputs.version }}
+          git push origin v${{ github.event.inputs.version }}
+
+      - name: Create GitHub Release
+        uses: actions/create-release@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          tag_name: v${{ github.event.inputs.version }}
+          release_name: v${{ github.event.inputs.version }}
+          draft: true
+          prerelease: false
@@ -0,0 +1,215 @@
+# CLAUDE.md - Boiler Auxiliary Heater Custom Integration
+
+## Purpose
+
+Home Assistant custom integration (`boiler_aux_heater_3phase`) that manages an auxiliary electric heater mounted inside a DHW (Domestic Hot Water) boiler. The boiler's primary heat source is a heat pump; this integration controls a secondary resistive heater for:
+
+- **PV excess utilization** - diverts surplus solar export to the heater instead of feeding back to the grid
+- **Boost heating** - rapid hot water via bath boost timer with optional circulation pump control
+- **Preset-based temperature control** - Normal, Eco, Boost, Sleep, Away presets with adjustable target temperatures
+- **All-modes boost** - allow the aux heater to run whenever the thermostat demands heat (not just PV/bath boost)
+- **Manual override** - force heater ON for testing/emergency
+
+## Architecture Overview
+
+The integration follows a coordinator pattern. `BoilerAuxHeaterCoordinator` is the central brain that:
+1. Listens to external entity state changes (boiler temp, grid power, relay state, heat pump aux heater)
+2. Reads internal entity states (switches, numbers) via direct references
+3. Runs decision logic to determine whether the heater relay should be ON or OFF
+4. Controls the physical relay via `switch.turn_on`/`switch.turn_off` service calls
+
+All entities register themselves with the coordinator on `async_added_to_hass` and receive updates via a listener callback pattern (not HA's `DataUpdateCoordinator`).
+
+```
+External sensors (boiler temp, CT power x1-3, HP aux heater, relay state)
+    |
+    v  (async_track_state_change_event + debounce)
+BoilerAuxHeaterCoordinator._recalculate()
+    |
+    +-- reads switch states (manual_override, allow_usage, pv_excess_mode, boost_all_modes)
+    +-- reads number values (cut_off_temp, heater_power, pv_buffer, pv_target_temp, etc.)
+    +-- runs PV state machine (idle -> waiting_start -> active -> waiting_stop)
+    +-- computes main thermostat heating (hysteresis against climate target temp)
+    +-- computes all-modes heating demand (separate larger hysteresis + recovery offset)
+    +-- computes final decision = manual_override OR (safety_ok AND (pv_heating OR bath_boost OR all_modes_boost))
+    |
+    v
+Controls physical relay + notifies all entity listeners to update HA state
+```
+
+## File Structure
+
+| File | Purpose |
+|------|---------|
+| `__init__.py` | Entry setup/unload, service registration (`start_bath_boost`, `stop_bath_boost`), options update listener |
+| `const.py` | All constants: domain, config keys, presets, number/switch definitions, tolerances |
+| `coordinator.py` | `BoilerAuxHeaterCoordinator` - central logic, PV state machine, bath boost timer, relay control |
+| `config_flow.py` | 3-step config flow (core hardware, solar sensors, optional devices) + options flow |
+| `climate.py` | `BoilerAuxHeaterClimate` - climate entity with presets, reads boiler temp from external sensor |
+| `binary_sensor.py` | 5 binary sensors: decision, pv_sufficient, running_on_pv, running_on_grid, bath_boost_active |
+| `sensor.py` | Power sensors (total/pv/grid), energy sensors (Riemann sum), bath boost remaining timer, decision_reason, pv_state |
+| `switch.py` | 4 config switches: manual_override, allow_usage, pv_excess_mode, boost_all_modes |
+| `number.py` | 15 configurable number entities (temperatures, thresholds, delays, power rating, etc.) |
+| `button.py` | Bath boost start + cancel buttons (only created if circulation pump is configured) |
+| `services.yaml` | Service definitions for `start_bath_boost` and `stop_bath_boost` |
+| `strings.json` | UI strings for config flow and entity names |
+| `translations/en.json` | English translations (mirrors strings.json + entity translations) |
+| `manifest.json` | Integration manifest: domain=`boiler_aux_heater_3phase`, version=1.0.0, iot_class=local_push |
+| `dashboard.yaml` | Ready-to-import Lovelace dashboard for monitoring and control |
+
+## Key Classes
+
+### `BoilerAuxHeaterCoordinator` (coordinator.py)
+
+Central state manager. **Not** a subclass of HA's `DataUpdateCoordinator` - uses a custom listener pattern instead.
+
+**State tracked:**
+- `pv_state` - PV state machine: `idle` / `waiting_to_start` / `active` / `waiting_to_stop`
+- `bath_boost_active` - whether bath boost is running
+- `decision` - final ON/OFF decision for the relay
+- `decision_reason` - human-readable string explaining the current decision
+- `pv_sufficient` - whether PV export exceeds heater power needs
+- `relay_is_on` - current physical relay state (read from external entity)
+- `pv_shadow_heating` - whether PV shadow thermostat logic wants heating
+
+**Entity registration:** Internal entities call `register_number(key, entity)`, `register_switch(key, entity)`, `register_climate(entity)` during setup. The coordinator reads their values directly via `get_number_value(key)` and `get_switch_state(key)`.
+
+**External state listening:** Tracks state changes on configured external entities (boiler temp sensor, 1-3x CT power sensors, heater relay, optionally HP aux heater). Changes are debounced (1s) before triggering `_recalculate()`.
+
+**PV State Machine:**
+- `idle` -> `waiting_to_start` when PV is sufficient (starts delay timer)
+- `waiting_to_start` -> `active` when start delay elapses and PV still sufficient
+- `waiting_to_start` -> `idle` if PV drops before delay
+- `active` -> `waiting_to_stop` when PV drops (starts stop delay timer)
+- `waiting_to_stop` -> `active` if PV recovers before stop delay
+- `waiting_to_stop` -> `idle` when stop delay elapses
+
+**Bath Boost Flow:**
+1. `async_start_bath_boost()` stores pre-boost preset, turns on circulation pump, sets climate to Boost preset, starts countdown timer
+2. `async_stop_bath_boost()` can be called manually (cancel button / service) to end early
+3. `_bath_boost_finished()` callback fires when timer expires - turns off boost, restores pump schedule, restores previous preset, fires HA event
+
+**Boost State Persistence:** Bath boost state (active, end_time, pre_boost_preset) is persisted to HA storage so it survives HA restarts.
+
+### `BoilerAuxHeaterClimate` (climate.py)
+
+Single climate entity with:
+- HVAC modes: `heat`, `off`
+- Presets: Normal, Eco, Boost, Sleep, Away
+- Uses `RestoreEntity` to persist state across restarts
+- `current_temperature` reads from external boiler temp sensor
+- `hvac_action` reports HEATING when relay is on, IDLE when off
+- Setting a preset reads the target temp from the corresponding number entity
+- Setting Boost preset activates `bath_boost_active` on coordinator; any other preset deactivates it (calls `async_stop_bath_boost`)
+
+### Energy Sensors (sensor.py)
+
+`BoilerEnergySensor` uses internal Riemann sum integration (not HA's `integration` platform). It accumulates energy by multiplying the heater power rating by elapsed time on each coordinator update. Uses `RestoreEntity` + `SensorStateClass.TOTAL_INCREASING` for long-term tracking. Tracks total, PV-only, and grid-only energy separately.
+
+A periodic 60-second energy tick (`async_track_time_interval`) notifies listeners to accumulate energy during steady state when no external events fire.
+
+### `PvTargetTempNumber` (number.py)
+
+Special subclass of `BoilerAuxHeaterNumber` whose `native_max_value` is dynamically capped at `cut_off_temp - 1`, preventing the PV target from exceeding the safety cut-off.
+
+## Decision Logic (coordinator.py:_recalculate)
+
+The heater relay is turned ON when (evaluated in priority order):
+
+```
+1. manual_override                                          → ON (bypasses everything)
+2. NOT allow_usage                                          → OFF
+3. hp_aux_heater sensor unavailable                        → OFF (safety)
+4. hp_aux_on                                               → OFF (interlock)
+5. boiler_temp >= cut_off_temp                             → OFF (safety)
+6. hvac_mode == "off"                                      → OFF
+7. pv_excess_mode AND pv_shadow_heating                    → ON (PV excess)
+8. bath_boost_active AND main_thermostat_heating            → ON (bath boost)
+9. boost_all_modes AND all_modes_heating_demand             → ON (all-modes boost)
+10. otherwise                                              → OFF
+```
+
+**Safety defaults for unavailable sensors:**
+- Boiler temperature: defaults to `100.0` (heater stays OFF - above any cut-off)
+- CT power sensors: default to `0.0` (no export detected - PV won't trigger)
+- HP aux heater: treated as ON (heater disabled) if unavailable - SAFETY interlock
+
+**PV sufficient calculation (supports 1 or 3 phases):**
+- When relay is OFF: each active CT phase must export more than `(buffer + heater_power) / phase_count`
+- When relay is ON (hysteresis): each active phase must still be exporting (value <= 0)
+
+**Main thermostat heating (hysteresis):**
+- Turns ON when `boiler_temp < target - temp_hysteresis`
+- Turns OFF when `boiler_temp >= target + MAIN_HOT_TOLERANCE (0.0)`
+
+**All-modes heating demand (separate, larger hysteresis):**
+- Turns ON when `boiler_temp < target - boost_all_modes_hysteresis`
+- Turns OFF when `boiler_temp >= target - boost_recovery_offset`
+
+## Config Flow (config_flow.py)
+
+3-step wizard:
+1. **Core Hardware**: boiler temp sensor (temperature device class) + heater relay switch
+2. **Solar Monitoring**: phase count (1 or 3) + CT power sensors (power device class) for grid monitoring
+3. **Optional Devices**: HP aux heater sensor (interlock), circulation pump switch (enables bath boost), pump schedule entity
+
+Uses `async_set_unique_id(DOMAIN)` + `_abort_if_unique_id_configured()` - only one instance allowed.
+
+Options flow allows reconfiguring all entity references post-setup.
+
+## Configurable Parameters (number entities, defined in const.py)
+
+| Key | Default | Range | Purpose |
+|-----|---------|-------|---------|
+| `cut_off_temp` | 60 | 40-85 °C | Hard safety limit - heater stops above this |
+| `temp_hysteresis` | 4 | 1-15 °C | Hysteresis for main thermostat and PV shadow thermostat |
+| `pv_target_temp` | 55 | 40-70 °C | Target temp for PV shadow thermostat (max capped at cut_off - 1) |
+| `pv_buffer` | 100 | 0-1000 W | Extra export required before PV triggers |
+| `heater_power` | 4500 | 1500-9000 W | Heater wattage (used for PV threshold + energy calc) |
+| `pv_start_delay` | 60 | 1-300 s | Delay before activating PV mode |
+| `pv_stop_delay` | 60 | 1-300 s | Delay before deactivating PV mode |
+| `temp_normal` | 44 | 30-65 °C | Normal preset target |
+| `temp_eco` | 40 | 30-60 °C | Eco preset target |
+| `temp_boost` | 50 | 40-70 °C | Boost preset target |
+| `temp_sleep` | 38 | 25-55 °C | Sleep preset target |
+| `temp_away` | 35 | 20-50 °C | Away preset target |
+| `bath_boost_duration` | 30 | 5-120 min | How long bath boost runs |
+| `boost_all_modes_hysteresis` | 10 | 3-20 °C | How far below target before all-modes boost activates |
+| `boost_recovery_offset` | 3 | 0-15 °C | How close to target before all-modes boost deactivates |
+
+## Mode Switches (switch entities, defined in const.py)
+
+| Key | Default | Purpose |
+|-----|---------|---------|
+| `manual_override` | OFF | Bypass all logic, force relay ON |
+| `allow_usage` | ON | Master enable for aux heater |
+| `pv_excess_mode` | ON | Enable PV excess diversion |
+| `boost_all_modes` | OFF | Allow main thermostat to trigger relay outside PV/bath boost modes |
+
+## Known Issues / Design Notes
+
+1. **Custom coordinator pattern** - Does not extend `homeassistant.helpers.update_coordinator.DataUpdateCoordinator`. Uses its own listener list and manual `_notify_listeners()`. This means no built-in polling fallback.
+
+2. **Energy sensors use `time.monotonic()`** - Energy integration accuracy depends on how frequently `_recalculate` fires (debounced to 1s on external state changes) plus the 60s periodic tick. Long periods without either would not accumulate energy.
+
+3. **Single instance only** - Config flow enforces one instance via unique_id. Multiple boiler setups would need code changes.
+
+4. **3-phase assumption for full accuracy** - PV calculation with 3 phases requires all 3 phases to independently meet the threshold. Single-phase mode supported (only CT1 used).
+
+5. **Bath boost button conditional** - `button.py` only creates the bath boost buttons if `circulation_pump` is configured. The `start_bath_boost`/`stop_bath_boost` services are always registered regardless.
+
+6. **Relay control via service calls** - The coordinator calls `switch.turn_on`/`turn_off` services to control the relay rather than directly setting state. Failure is caught and logged but doesn't retry.
+
+7. **`_enable_turn_on_off_backwards_compat = False`** in climate - opts out of HA 2024.x backwards compatibility for `turn_on`/`turn_off`.
+
+8. **No `async_setup` (YAML config)** - Integration only supports config entries (UI setup), not YAML configuration.
+
+## Patterns Used
+
+- **RestoreEntity** on climate, switch, number, and energy sensors for state persistence across restarts
+- **Persistent storage** (`homeassistant.helpers.storage.Store`) for bath boost state across restarts
+- **Entity registration with coordinator** via `register_*()` methods during `async_added_to_hass`
+- **Data-driven entity creation** from `NUMBER_DEFINITIONS`, `SWITCH_DEFINITIONS`, `BINARY_SENSOR_DEFINITIONS` dicts
+- **Debounced state change handling** with `async_call_later` (1s debounce)
+- **Translation keys** (`_attr_translation_key`) for all entities with translations in `translations/en.json`
+- **DeviceInfo** with shared identifiers groups all entities under one device in HA
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+# Boiler Auxiliary Heater Control
+
+A Home Assistant custom integration for intelligently controlling an auxiliary electric heating element inside a DHW (Domestic Hot Water) boiler. Designed for systems where a heat pump is the primary heat source and an electric resistance heater is the secondary element.
+
+The integration maximises PV self-consumption by diverting surplus solar energy to the boiler, while also supporting on-demand bath boost heating and fully configurable temperature presets.
+
+---
+
+## Features
+
+- **PV Excess Diversion** — monitors up to 3 CT clamps (single-phase or 3-phase) and activates the heater only when there is enough surplus export, using configurable start/stop delays to avoid rapid cycling
+- **Bath Boost** — one-tap hot water on demand; activates the heater and optionally runs the DHW circulation pump for a configurable duration, then automatically restores the previous state
+- **5 Temperature Presets** — Normal, Eco, Boost, Sleep, Away, each with individually adjustable target temperatures
+- **All-Modes Boost** — optional mode that lets the aux heater top up the boiler whenever the thermostat demands heat, regardless of PV availability
+- **Safety Interlocks** — hard cut-off temperature, HP aux heater interlock (disables aux heater while the heat pump's own electric element is running), and safe defaults for unavailable sensors
+- **Energy Tracking** — separate kWh counters for total, PV-sourced, and grid-sourced energy, compatible with HA's Energy Dashboard
+- **Decision Transparency** — a `Decision Reason` sensor tells you exactly why the heater is on or off at any moment
+- **Persistent State** — all settings and an active bath boost survive HA restarts
+- **Ready-to-Use Dashboard** — an importable Lovelace dashboard is included
+
+---
+
+## Requirements
+
+- Home Assistant 2024.1.0 or newer
+- A temperature sensor measuring the boiler water temperature (device class: `temperature`)
+- A switch entity controlling the heater relay
+- One or more power sensors measuring grid import/export at each phase (device class: `power`, **negative = export**)
+
+Optional:
+- A binary sensor indicating whether the heat pump's own auxiliary heater is active (for interlock)
+- A switch entity for a DHW circulation pump (enables the bath boost button)
+- A scheduler entity for the pump (its schedule is restored after bath boost)
+
+---
+
+## Installation
+
+### Via HACS (recommended)
+
+1. Open HACS in Home Assistant
+2. Go to **Integrations** → click the three-dot menu → **Custom repositories**
+3. Add this repository URL and select category **Integration**
+4. Search for **Boiler Auxiliary Heater Control** and install
+5. Restart Home Assistant
+
+### Manual
+
+1. Copy the `custom_components/boiler_aux_heater_3phase` folder into your HA `config/custom_components/` directory
+2. Restart Home Assistant
+
+---
+
+## Configuration
+
+Navigate to **Settings → Devices & Services → Add Integration** and search for **Boiler Auxiliary Heater Control**.
+
+The setup wizard has three steps:
+
+### Step 1 — Core Hardware
+
+| Field | Description |
+|-------|-------------|
+| Boiler temperature sensor | Sensor measuring the DHW tank temperature (must have device class `temperature`) |
+| Heater relay switch | The switch entity that controls the heating element |
+
+### Step 2 — Solar Monitoring
+
+| Field | Description |
+|-------|-------------|
+| Number of phases | `1 Phase` or `3 Phases` |
+| Phase 1 CT power sensor | Grid power sensor for phase 1 (negative = exporting) |
+| Phase 2 CT power sensor | Phase 2 sensor (3-phase only, optional) |
+| Phase 3 CT power sensor | Phase 3 sensor (3-phase only, optional) |
+
+> **Important:** the CT sensors must report **negative values for export** and positive values for import. This is the convention used by most inverter integrations (Fronius, SolarEdge, Huawei, etc.).
+
+### Step 3 — Optional Devices
+
+| Field | Description |
+|-------|-------------|
+| HP aux heater sensor | Binary sensor that is `on` when the heat pump's own electric element is active. If provided, the aux heater is disabled while this sensor is `on`. If the sensor becomes **unavailable**, the aux heater is disabled as a safety measure. |
+| Circulation pump switch | Switch controlling a DHW circulation pump. When provided, the **Bath Boost** button entities are created. |
+| Pump schedule entity | A scheduler entity whose schedule is re-applied after bath boost finishes. |
+
+After initial setup, all entity references can be changed via **Configure** on the integration card.
+
+---
+
+## Entities
+
+### Climate
+
+| Entity | Description |
+|--------|-------------|
+| `climate.boiler_auxiliary_heater` | Main thermostat. Set HVAC mode (`heat`/`off`) and choose a preset. |
+
+**Presets:** Normal · Eco · Boost · Sleep · Away
+
+Selecting the **Boost** preset starts the bath boost timer. Selecting any other preset while boost is active cancels the boost.
+
+---
+
+### Switches (Configuration)
+
+| Entity | Default | Description |
+|--------|---------|-------------|
+| `switch…allow_aux_heater_usage` | ON | Master enable. Turn off to disable the aux heater entirely. |
+| `switch…pv_excess_mode` | ON | Enable PV excess diversion. |
+| `switch…boost_in_all_modes` | OFF | Allow the heater to run whenever the thermostat demands heat, regardless of PV. Uses the larger all-modes hysteresis to avoid short cycling. |
+| `switch…manual_override` | OFF | Force the relay ON, bypassing all logic. For testing or emergencies only. |
+
+---
+
+### Numbers (Configuration)
+
+**Temperatures**
+
+| Entity | Default | Range | Description |
+|--------|---------|-------|-------------|
+| `number…cut_off_temperature` | 60 °C | 40–85 | Hard safety limit. Heater is always off above this temperature. |
+| `number…temperature_hysteresis` | 4 °C | 1–15 | How far below the target temperature heating must be demanded before activating. Also used as PV shadow thermostat cold tolerance. |
+| `number…pv_target_temperature` | 55 °C | 40–70 | Target temperature for PV excess mode. Max is automatically capped at `cut_off_temp - 1`. |
+| `number…normal_preset_temperature` | 44 °C | 30–65 | Target for Normal preset. |
+| `number…eco_preset_temperature` | 40 °C | 30–60 | Target for Eco preset. |
+| `number…boost_preset_temperature` | 50 °C | 40–70 | Target for Boost preset. |
+| `number…sleep_preset_temperature` | 38 °C | 25–55 | Target for Sleep preset. |
+| `number…away_preset_temperature` | 35 °C | 20–50 | Target for Away preset. |
+
+**PV Excess Settings**
+
+| Entity | Default | Range | Description |
+|--------|---------|-------|-------------|
+| `number…heater_power_rating` | 4500 W | 1500–9000 | Rated wattage of the heating element. Used for PV surplus threshold and energy calculations. |
+| `number…pv_excess_buffer` | 100 W | 0–1000 | Additional margin required above heater power before PV mode activates. Prevents marginal activation. |
+| `number…pv_excess_start_delay` | 60 s | 1–300 | How long PV surplus must be sustained before activating. Prevents cloud transients from triggering the heater. |
+| `number…pv_excess_stop_delay` | 60 s | 1–300 | How long PV deficit must be sustained before deactivating. Allows short shading events without turning off. |
+
+**Bath Boost & All-Modes Settings**
+
+| Entity | Default | Range | Description |
+|--------|---------|-------|-------------|
+| `number…bath_boost_duration` | 30 min | 5–120 | How long bath boost runs. |
+| `number…all_modes_boost_hysteresis` | 10 °C | 3–20 | Temperature must be this far below target for all-modes boost to activate. Larger value → heater activates less often. |
+| `number…boost_recovery_offset` | 3 °C | 0–15 | All-modes boost turns off when temperature reaches `target - boost_recovery_offset`. |
+
+---
+
+### Binary Sensors (Status)
+
+| Entity | Description |
+|--------|-------------|
+| `binary_sensor…heater_decision` | `on` = heater relay should be on right now. |
+| `binary_sensor…pv_power_sufficient` | `on` = current PV export is enough to run the heater. |
+| `binary_sensor…running_on_pv` | `on` = heater is running and powered by PV surplus. |
+| `binary_sensor…running_on_grid` | `on` = heater is running on grid power (bath boost or all-modes boost). |
+| `binary_sensor…bath_boost_active` | `on` = bath boost timer is running. |
+
+---
+
+### Sensors (Status)
+
+| Entity | Description |
+|--------|-------------|
+| `sensor…heater_power` | Current total power consumption of the heater (W). |
+| `sensor…heater_pv_power` | Current power drawn from PV surplus (W). |
+| `sensor…heater_grid_power` | Current power drawn from the grid (W). |
+| `sensor…heater_energy` | Total energy consumed (kWh) — suitable for HA Energy Dashboard. |
+| `sensor…heater_pv_energy` | Energy consumed from PV (kWh). |
+| `sensor…heater_grid_energy` | Energy consumed from grid (kWh). |
+| `sensor…bath_boost_remaining` | Seconds remaining in the current bath boost (0 when inactive). |
+| `sensor…decision_reason` | Human-readable text explaining the current heater decision, e.g. *"PV excess heating"* or *"OFF: HP aux heater active"*. |
+| `sensor…pv_excess_state` | PV state machine state: `idle`, `waiting_to_start`, `active`, or `waiting_to_stop`. |
+
+---
+
+### Buttons (optional — only if circulation pump is configured)
+
+| Entity | Description |
+|--------|-------------|
+| `button…start_bath_boost` | Start the bath boost timer immediately. |
+| `button…cancel_bath_boost` | Cancel an active bath boost and restore previous state. |
+
+---
+
+## Services
+
+Both services are always available, regardless of whether a circulation pump is configured.
+
+### `boiler_aux_heater_3phase.start_bath_boost`
+
+Starts the bath boost. Saves the current climate preset, activates the Boost preset, starts the countdown timer, and (if configured) turns on the circulation pump.
+
+```yaml
+service: boiler_aux_heater_3phase.start_bath_boost
+```
+
+### `boiler_aux_heater_3phase.stop_bath_boost`
+
+Cancels an active bath boost, restores the previous preset, and (if configured) turns off the circulation pump and re-applies the pump schedule.
+
+```yaml
+service: boiler_aux_heater_3phase.stop_bath_boost
+```
+
+---
+
+## Events
+
+When a bath boost expires naturally (timer runs out), the integration fires:
+
+```
+event: boiler_aux_heater_3phase_boost_finished
+data:
+  duration_minutes: 30
+  pre_boost_preset: "Normal"
+  restored_preset: "Normal"
+```
+
+You can use this event in automations to notify occupants or take further action.
+
+---
+
+## How the PV Excess Logic Works
+
+```
+For each active CT phase:
+  Turn-on threshold:  CT_value < -(heater_power / phases + pv_buffer / phases)
+  Stay-on threshold:  CT_value <= 0   (any export at all)
+
+State machine:
+  IDLE  ──[all phases meet turn-on threshold]──►  WAITING_TO_START
+  WAITING_TO_START  ──[pv_start_delay elapsed]──►  ACTIVE
+  WAITING_TO_START  ──[PV drops]──►  IDLE
+  ACTIVE  ──[any phase stops exporting]──►  WAITING_TO_STOP
+  WAITING_TO_STOP  ──[pv_stop_delay elapsed]──►  IDLE
+  WAITING_TO_STOP  ──[PV recovers]──►  ACTIVE
+```
+
+While in `ACTIVE` or `WAITING_TO_STOP`, the PV shadow thermostat checks whether the boiler temperature is below `pv_target_temp`. This prevents unnecessarily overheating the tank on very sunny days.
+
+---
+
+## Dashboard
+
+A ready-to-use Lovelace dashboard is included in `custom_components/boiler_aux_heater_3phase/dashboard.yaml`.
+
+To import it:
+1. Go to **Settings → Dashboards → Add Dashboard**
+2. Or use the **Raw Configuration Editor** in an existing dashboard and paste the YAML
+
+The dashboard includes sections for:
+- Thermostat control with preset dropdown
+- Bath boost controls and timer
+- Mode switches
+- Preset temperature configuration
+- Safety and heater settings
+- PV excess settings
+- Live status (decision, PV state, power & energy)
+
+---
+
+## Automation Examples
+
+### Notify when bath boost finishes
+
+```yaml
+automation:
+  - alias: "Notify bath boost done"
+    trigger:
+      - platform: event
+        event_type: boiler_aux_heater_3phase_boost_finished
+    action:
+      - service: notify.mobile_app_my_phone
+        data:
+          message: "Hot water ready! Tank heated for {{ trigger.event.data.duration_minutes }} minutes."
+```
+
+### Switch to Away preset when leaving home
+
+```yaml
+automation:
+  - alias: "Boiler away mode"
+    trigger:
+      - platform: state
+        entity_id: person.resident
+        to: not_home
+    action:
+      - service: climate.set_preset_mode
+        target:
+          entity_id: climate.boiler_auxiliary_heater
+        data:
+          preset_mode: Away
+```
+
+### Start bath boost on a schedule
+
+```yaml
+automation:
+  - alias: "Morning bath boost"
+    trigger:
+      - platform: time
+        at: "07:00:00"
+    condition:
+      - condition: state
+        entity_id: binary_sensor.workday_sensor
+        state: "on"
+    action:
+      - service: boiler_aux_heater_3phase.start_bath_boost
+```
+
+---
+
+## Troubleshooting
+
+**Heater never activates in PV mode**
+- Check `sensor…pv_excess_state` — if it stays `idle`, the CT sensors may not be reporting negative values when exporting. Confirm the sign convention of your inverter integration.
+- Check that `switch…pv_excess_mode` is on and `switch…allow_aux_heater_usage` is on.
+- Check `sensor…decision_reason` for the exact reason the heater is off.
+- Increase `pv_excess_buffer` to 0 temporarily to rule out threshold issues.
+
+**HP aux heater interlock keeps the heater off**
+- If the HP aux heater binary sensor reads `unavailable`, the integration disables the aux heater as a safety measure. Check the sensor entity or remove it from the configuration if not needed.
+
+**Bath boost buttons are missing**
+- The bath boost buttons are only created when a circulation pump switch is configured. Go to **Configure** on the integration card to add one. The `start_bath_boost` and `stop_bath_boost` services are always available regardless.
+
+**Energy counters reset after restart**
+- Energy sensors use `RestoreEntity` to persist their values. If values are lost, check that the HA recorder is running and that the entities are not excluded from recording.
+
+**PV mode activates but heater stays off**
+- Check `sensor…decision_reason`. Common causes: boiler temperature above `cut_off_temperature`, HVAC mode set to `off`, or `allow_aux_heater_usage` switch is off.
+
+---
+
+## License
+
+MIT License — see [LICENSE](LICENSE) for details.
@@ -0,0 +1,82 @@
+"""Boiler Auxiliary Heater Control integration."""
+
+from __future__ import annotations
+
+import logging
+
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.core import HomeAssistant, ServiceCall
+
+from .const import DOMAIN, PLATFORMS
+from .coordinator import BoilerAuxHeaterCoordinator
+
+_LOGGER = logging.getLogger(__name__)
+
+
+async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
+    """Set up Boiler Auxiliary Heater from a config entry."""
+    config = {**entry.data, **entry.options}
+
+    coordinator = BoilerAuxHeaterCoordinator(hass, config)
+
+    hass.data.setdefault(DOMAIN, {})
+    hass.data[DOMAIN][entry.entry_id] = coordinator
+
+    await hass.config_entries.async_forward_entry_setups(entry, PLATFORMS)
+
+    # Start listening to external entities after platforms are set up
+    await coordinator.async_setup()
+
+    # Register services
+    async def handle_start_bath_boost(call: ServiceCall) -> None:
+        """Handle the start_bath_boost service call."""
+        for coord in hass.data[DOMAIN].values():
+            if isinstance(coord, BoilerAuxHeaterCoordinator):
+                await coord.async_start_bath_boost()
+
+    async def handle_stop_bath_boost(call: ServiceCall) -> None:
+        """Handle the stop_bath_boost service call."""
+        for coord in hass.data[DOMAIN].values():
+            if isinstance(coord, BoilerAuxHeaterCoordinator):
+                await coord.async_stop_bath_boost()
+
+    hass.services.async_register(
+        DOMAIN, "start_bath_boost", handle_start_bath_boost
+    )
+    hass.services.async_register(
+        DOMAIN, "stop_bath_boost", handle_stop_bath_boost
+    )
+
+    # Listen for options updates
+    entry.async_on_unload(entry.add_update_listener(async_options_updated))
+
+    return True
+
+
+async def async_options_updated(
+    hass: HomeAssistant, entry: ConfigEntry
+) -> None:
+    """Handle options update."""
+    coordinator: BoilerAuxHeaterCoordinator = hass.data[DOMAIN][entry.entry_id]
+    new_config = {**entry.data, **entry.options}
+    coordinator.update_config(new_config)
+
+    # B8: Only shut down external listeners, preserve boost timer and PV delays
+    coordinator._async_shutdown_listeners()
+    await coordinator.async_setup()
+
+
+async def async_unload_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
+    """Unload a config entry."""
+    coordinator: BoilerAuxHeaterCoordinator = hass.data[DOMAIN][entry.entry_id]
+    await coordinator.async_shutdown()
+
+    unload_ok = await hass.config_entries.async_unload_platforms(entry, PLATFORMS)
+    if unload_ok:
+        hass.data[DOMAIN].pop(entry.entry_id)
+        # Remove services if no more entries
+        if not hass.data[DOMAIN]:
+            hass.services.async_remove(DOMAIN, "start_bath_boost")
+            hass.services.async_remove(DOMAIN, "stop_bath_boost")
+
+    return unload_ok
@@ -0,0 +1,130 @@
+"""Binary sensor entities for Boiler Auxiliary Heater Control."""
+
+from __future__ import annotations
+
+from homeassistant.components.binary_sensor import (
+    BinarySensorDeviceClass,
+    BinarySensorEntity,
+)
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.core import HomeAssistant, callback
+from homeassistant.helpers.entity import DeviceInfo
+from homeassistant.helpers.entity_platform import AddEntitiesCallback
+
+from .const import DOMAIN
+
+BINARY_SENSOR_DEFINITIONS = {
+    "decision": {
+        "name": "Heater Decision",
+        "icon_on": "mdi:water-boiler",
+        "icon_off": "mdi:water-boiler-off",
+        "device_class": None,
+    },
+    "pv_sufficient": {
+        "name": "PV Power Sufficient",
+        "icon_on": "mdi:solar-power",
+        "icon_off": "mdi:solar-power-variant-outline",
+        "device_class": BinarySensorDeviceClass.POWER,
+    },
+    "running_on_pv": {
+        "name": "Running on PV",
+        "icon_on": "mdi:solar-power",
+        "icon_off": "mdi:solar-power-variant-outline",
+        "device_class": None,
+    },
+    "running_on_grid": {
+        "name": "Running on Grid",
+        "icon_on": "mdi:transmission-tower",
+        "icon_off": "mdi:transmission-tower-off",
+        "device_class": None,
+    },
+    "bath_boost_active": {
+        "name": "Bath Boost Active",
+        "icon_on": "mdi:flash",
+        "icon_off": "mdi:flash-off",
+        "device_class": None,
+    },
+}
+
+
+async def async_setup_entry(
+    hass: HomeAssistant,
+    entry: ConfigEntry,
+    async_add_entities: AddEntitiesCallback,
+) -> None:
+    """Set up binary sensor entities."""
+    coordinator = hass.data[DOMAIN][entry.entry_id]
+
+    entities = []
+    for key, defn in BINARY_SENSOR_DEFINITIONS.items():
+        entities.append(
+            BoilerAuxHeaterBinarySensor(coordinator, entry, key, defn)
+        )
+
+    async_add_entities(entities)
+
+
+class BoilerAuxHeaterBinarySensor(BinarySensorEntity):
+    """A computed binary sensor for the boiler aux heater."""
+
+    _attr_has_entity_name = True
+
+    def __init__(
+        self,
+        coordinator,
+        entry: ConfigEntry,
+        key: str,
+        defn: dict,
+    ) -> None:
+        """Initialize the binary sensor."""
+        self.coordinator = coordinator
+        self._key = key
+        self._defn = defn
+        self._attr_unique_id = f"{entry.entry_id}_{key}"
+        self._attr_translation_key = key
+        if defn["device_class"]:
+            self._attr_device_class = defn["device_class"]
+        self._unsub_listener = None
+        self._attr_device_info = DeviceInfo(
+            identifiers={(DOMAIN, entry.entry_id)},
+            name="Boiler Auxiliary Heater",
+            manufacturer="Custom",
+        )
+
+    async def async_added_to_hass(self) -> None:
+        """Register with coordinator for updates."""
+        self._unsub_listener = self.coordinator.async_add_listener(
+            self._handle_coordinator_update
+        )
+
+    async def async_will_remove_from_hass(self) -> None:
+        """Clean up listener."""
+        if self._unsub_listener:
+            self._unsub_listener()
+
+    @callback
+    def _handle_coordinator_update(self) -> None:
+        """Update state from coordinator."""
+        self.async_write_ha_state()
+
+    @property
+    def is_on(self) -> bool:
+        """Return computed state from coordinator."""
+        if self._key == "decision":
+            return self.coordinator.decision
+        if self._key == "pv_sufficient":
+            return self.coordinator.pv_sufficient
+        if self._key == "running_on_pv":
+            return self.coordinator.relay_is_on and self.coordinator.pv_sufficient
+        if self._key == "running_on_grid":
+            return self.coordinator.relay_is_on and not self.coordinator.pv_sufficient
+        if self._key == "bath_boost_active":
+            return self.coordinator.bath_boost_active
+        return False
+
+    @property
+    def icon(self) -> str:
+        """Return icon based on state."""
+        if self.is_on:
+            return self._defn["icon_on"]
+        return self._defn["icon_off"]
@@ -0,0 +1,74 @@
+"""Button entity for Boiler Auxiliary Heater Control."""
+
+from __future__ import annotations
+
+from homeassistant.components.button import ButtonEntity
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers.entity import DeviceInfo
+from homeassistant.helpers.entity_platform import AddEntitiesCallback
+
+from .const import DOMAIN
+
+
+async def async_setup_entry(
+    hass: HomeAssistant,
+    entry: ConfigEntry,
+    async_add_entities: AddEntitiesCallback,
+) -> None:
+    """Set up button entities."""
+    coordinator = hass.data[DOMAIN][entry.entry_id]
+
+    entities: list[ButtonEntity] = []
+
+    # Only create bath boost buttons if circulation pump is configured
+    if coordinator.circulation_pump:
+        entities.append(BoilerBathBoostButton(coordinator, entry))
+        entities.append(BoilerCancelBathBoostButton(coordinator, entry))
+
+    if entities:
+        async_add_entities(entities)
+
+
+class BoilerBathBoostButton(ButtonEntity):
+    """Button to start the bath boost timer."""
+
+    _attr_has_entity_name = True
+    _attr_translation_key = "start_bath_boost"
+    _attr_icon = "mdi:bath"
+
+    def __init__(self, coordinator, entry: ConfigEntry) -> None:
+        """Initialize the button."""
+        self.coordinator = coordinator
+        self._attr_unique_id = f"{entry.entry_id}_start_bath_boost"
+        self._attr_device_info = DeviceInfo(
+            identifiers={(DOMAIN, entry.entry_id)},
+            name="Boiler Auxiliary Heater",
+            manufacturer="Custom",
+        )
+
+    async def async_press(self) -> None:
+        """Handle button press - start bath boost."""
+        await self.coordinator.async_start_bath_boost()
+
+
+class BoilerCancelBathBoostButton(ButtonEntity):
+    """Button to cancel an active bath boost (U1)."""
+
+    _attr_has_entity_name = True
+    _attr_translation_key = "cancel_bath_boost"
+    _attr_icon = "mdi:bath"
+
+    def __init__(self, coordinator, entry: ConfigEntry) -> None:
+        """Initialize the button."""
+        self.coordinator = coordinator
+        self._attr_unique_id = f"{entry.entry_id}_cancel_bath_boost"
+        self._attr_device_info = DeviceInfo(
+            identifiers={(DOMAIN, entry.entry_id)},
+            name="Boiler Auxiliary Heater",
+            manufacturer="Custom",
+        )
+
+    async def async_press(self) -> None:
+        """Handle button press - cancel bath boost."""
+        await self.coordinator.async_stop_bath_boost()
@@ -0,0 +1,184 @@
+"""Climate entity for Boiler Auxiliary Heater Control."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from homeassistant.components.climate import (
+    ClimateEntity,
+    ClimateEntityFeature,
+    HVACAction,
+    HVACMode,
+)
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.const import ATTR_TEMPERATURE, UnitOfTemperature
+from homeassistant.core import HomeAssistant, callback
+from homeassistant.helpers.entity import DeviceInfo
+from homeassistant.helpers.entity_platform import AddEntitiesCallback
+from homeassistant.helpers.restore_state import RestoreEntity
+
+from .const import (
+    DOMAIN,
+    PRESET_BOOST,
+    PRESET_NORMAL,
+    PRESET_TEMP_MAP,
+    PRESETS,
+)
+
+
+async def async_setup_entry(
+    hass: HomeAssistant,
+    entry: ConfigEntry,
+    async_add_entities: AddEntitiesCallback,
+) -> None:
+    """Set up the climate entity."""
+    coordinator = hass.data[DOMAIN][entry.entry_id]
+    entity = BoilerAuxHeaterClimate(coordinator, entry)
+    async_add_entities([entity])
+
+
+class BoilerAuxHeaterClimate(RestoreEntity, ClimateEntity):
+    """Unified climate entity with native presets and dual thermostat logic."""
+
+    _attr_has_entity_name = True
+    _attr_translation_key = "boiler_aux_heater"
+    _attr_temperature_unit = UnitOfTemperature.CELSIUS
+    _attr_hvac_modes = [HVACMode.HEAT, HVACMode.OFF]
+    _attr_supported_features = (
+        ClimateEntityFeature.TARGET_TEMPERATURE
+        | ClimateEntityFeature.PRESET_MODE
+        | ClimateEntityFeature.TURN_ON
+        | ClimateEntityFeature.TURN_OFF
+    )
+    _attr_min_temp = 10
+    _attr_max_temp = 70
+    _attr_target_temperature_step = 1
+    _attr_precision = 0.1
+    _enable_turn_on_off_backwards_compat = False
+
+    def __init__(self, coordinator, entry: ConfigEntry) -> None:
+        """Initialize the climate entity."""
+        self.coordinator = coordinator
+        self._attr_unique_id = f"{entry.entry_id}_climate"
+        self._attr_preset_modes = list(PRESETS)
+        self._attr_preset_mode = PRESET_NORMAL
+        self._attr_hvac_mode = HVACMode.HEAT
+        self._attr_target_temperature = 50.0
+        self._unsub_listener = None
+        self._attr_device_info = DeviceInfo(
+            identifiers={(DOMAIN, entry.entry_id)},
+            name="Boiler Auxiliary Heater",
+            manufacturer="Custom",
+        )
+
+    async def async_added_to_hass(self) -> None:
+        """Restore state and register with coordinator."""
+        await super().async_added_to_hass()
+
+        last_state = await self.async_get_last_state()
+        if last_state:
+            if last_state.state in ("heat", "off"):
+                self._attr_hvac_mode = HVACMode(last_state.state)
+            attrs = last_state.attributes
+            if "temperature" in attrs:
+                try:
+                    self._attr_target_temperature = float(attrs["temperature"])
+                except (ValueError, TypeError):
+                    pass
+            if "preset_mode" in attrs and attrs["preset_mode"] in PRESETS:
+                self._attr_preset_mode = attrs["preset_mode"]
+
+        # Register with coordinator
+        self.coordinator.register_climate(self)
+        self._unsub_listener = self.coordinator.async_add_listener(
+            self._handle_coordinator_update
+        )
+
+    async def async_will_remove_from_hass(self) -> None:
+        """Clean up listener."""
+        if self._unsub_listener:
+            self._unsub_listener()
+
+    @callback
+    def _handle_coordinator_update(self) -> None:
+        """Update entity when coordinator state changes."""
+        self.async_write_ha_state()
+
+    @property
+    def current_temperature(self) -> float | None:
+        """Return current boiler temperature from external sensor."""
+        state = self.hass.states.get(self.coordinator.boiler_temp_sensor)
+        if state is None or state.state in ("unknown", "unavailable"):
+            return None
+        try:
+            return float(state.state)
+        except (ValueError, TypeError):
+            return None
+
+    @property
+    def hvac_action(self) -> HVACAction:
+        """Return current action based on relay state."""
+        if self._attr_hvac_mode == HVACMode.OFF:
+            return HVACAction.OFF
+        if self.coordinator.relay_is_on:
+            return HVACAction.HEATING
+        return HVACAction.IDLE
+
+    async def async_set_hvac_mode(self, hvac_mode: HVACMode) -> None:
+        """Set HVAC mode."""
+        self._attr_hvac_mode = hvac_mode
+        if hvac_mode == HVACMode.OFF:
+            self._attr_preset_mode = None
+            # Stop boost if turning off
+            if self.coordinator.bath_boost_active:
+                await self.coordinator.async_stop_bath_boost()
+        self.async_write_ha_state()
+        self.coordinator.async_request_refresh()
+
+    async def async_set_temperature(self, **kwargs: Any) -> None:
+        """Set target temperature."""
+        if ATTR_TEMPERATURE in kwargs:
+            self._attr_target_temperature = kwargs[ATTR_TEMPERATURE]
+            self.async_write_ha_state()
+            self.coordinator.async_request_refresh()
+
+    async def async_set_preset_mode(self, preset_mode: str) -> None:
+        """Set preset mode and update target temperature from number entity."""
+
+        # Capture pre-boost preset BEFORE overwriting _attr_preset_mode
+        if preset_mode == PRESET_BOOST and not self.coordinator.bath_boost_active:
+            self.coordinator._pre_boost_preset = self._attr_preset_mode
+
+        self._attr_preset_mode = preset_mode
+        self._attr_hvac_mode = HVACMode.HEAT
+
+        # Get target temperature from the corresponding number entity
+        temp_key = PRESET_TEMP_MAP.get(preset_mode)
+        if temp_key:
+            temp = self.coordinator.get_number_value(temp_key)
+            if temp is not None:
+                self._attr_target_temperature = temp
+
+        # B2: Toggle bath boost via coordinator for proper lifecycle
+        if preset_mode == PRESET_BOOST:
+            if not self.coordinator.bath_boost_active:
+                self.async_write_ha_state()
+                await self.coordinator.async_start_bath_boost()
+                return
+        else:
+            if self.coordinator.bath_boost_active:
+                self.async_write_ha_state()
+                # restore_preset=False: _attr_preset_mode already holds the user's desired preset
+                await self.coordinator.async_stop_bath_boost(restore_preset=False)
+                return
+
+        self.async_write_ha_state()
+        self.coordinator.async_request_refresh()
+
+    async def async_turn_on(self) -> None:
+        """Turn the climate entity on (U4: voice assistant support)."""
+        await self.async_set_hvac_mode(HVACMode.HEAT)
+
+    async def async_turn_off(self) -> None:
+        """Turn the climate entity off (U4: voice assistant support)."""
+        await self.async_set_hvac_mode(HVACMode.OFF)
@@ -0,0 +1,254 @@
+"""Config flow for Boiler Auxiliary Heater Control."""
+
+from __future__ import annotations
+
+from typing import Any
+
+import voluptuous as vol
+
+from homeassistant.components.sensor import SensorDeviceClass
+from homeassistant.config_entries import ConfigEntry, ConfigFlow, OptionsFlow
+from homeassistant.const import Platform
+from homeassistant.core import callback
+from homeassistant.helpers import selector
+
+from .const import (
+    CONF_BOILER_TEMP_SENSOR,
+    CONF_CIRCULATION_PUMP,
+    CONF_CT1_POWER,
+    CONF_CT2_POWER,
+    CONF_CT3_POWER,
+    CONF_HEATER_RELAY,
+    CONF_HP_AUX_HEATER,
+    CONF_PHASE_COUNT,
+    CONF_PUMP_SCHEDULE,
+    DOMAIN,
+)
+
+
+class BoilerAuxHeaterConfigFlow(ConfigFlow, domain=DOMAIN):
+    """Handle a config flow for Boiler Auxiliary Heater Control."""
+
+    VERSION = 1
+
+    def __init__(self) -> None:
+        """Initialize flow."""
+        self._data: dict[str, Any] = {}
+
+    async def async_step_user(
+        self, user_input: dict[str, Any] | None = None
+    ) -> dict:
+        """Step 1: Core hardware - boiler temp sensor and heater relay."""
+        if user_input is not None:
+            self._data.update(user_input)
+            return await self.async_step_solar()
+
+        return self.async_show_form(
+            step_id="user",
+            data_schema=vol.Schema(
+                {
+                    vol.Required(CONF_BOILER_TEMP_SENSOR): selector.EntitySelector(
+                        selector.EntitySelectorConfig(
+                            domain=Platform.SENSOR,
+                            device_class=SensorDeviceClass.TEMPERATURE,
+                        )
+                    ),
+                    vol.Required(CONF_HEATER_RELAY): selector.EntitySelector(
+                        selector.EntitySelectorConfig(domain=Platform.SWITCH)
+                    ),
+                }
+            ),
+        )
+
+    async def async_step_solar(
+        self, user_input: dict[str, Any] | None = None
+    ) -> dict:
+        """Step 2: Solar monitoring - phase count and CT power sensors."""
+        if user_input is not None:
+            self._data.update(user_input)
+            return await self.async_step_optional()
+
+        return self.async_show_form(
+            step_id="solar",
+            data_schema=vol.Schema(
+                {
+                    vol.Required(CONF_PHASE_COUNT, default=3): selector.SelectSelector(
+                        selector.SelectSelectorConfig(
+                            options=[
+                                selector.SelectOptionDict(value="1", label="1 Phase"),
+                                selector.SelectOptionDict(value="3", label="3 Phases"),
+                            ],
+                            mode=selector.SelectSelectorMode.DROPDOWN,
+                        )
+                    ),
+                    vol.Required(CONF_CT1_POWER): selector.EntitySelector(
+                        selector.EntitySelectorConfig(
+                            domain=Platform.SENSOR,
+                            device_class=SensorDeviceClass.POWER,
+                        )
+                    ),
+                    vol.Optional(CONF_CT2_POWER): selector.EntitySelector(
+                        selector.EntitySelectorConfig(
+                            domain=Platform.SENSOR,
+                            device_class=SensorDeviceClass.POWER,
+                        )
+                    ),
+                    vol.Optional(CONF_CT3_POWER): selector.EntitySelector(
+                        selector.EntitySelectorConfig(
+                            domain=Platform.SENSOR,
+                            device_class=SensorDeviceClass.POWER,
+                        )
+                    ),
+                }
+            ),
+        )
+
+    async def async_step_optional(
+        self, user_input: dict[str, Any] | None = None
+    ) -> dict:
+        """Step 3: Optional devices."""
+        if user_input is not None:
+            self._data.update(user_input)
+            # Convert phase_count from string to int
+            if CONF_PHASE_COUNT in self._data:
+                self._data[CONF_PHASE_COUNT] = int(self._data[CONF_PHASE_COUNT])
+            await self.async_set_unique_id(DOMAIN)
+            self._abort_if_unique_id_configured()
+            return self.async_create_entry(
+                title="Boiler Auxiliary Heater",
+                data=self._data,
+            )
+
+        return self.async_show_form(
+            step_id="optional",
+            data_schema=vol.Schema(
+                {
+                    vol.Optional(CONF_HP_AUX_HEATER): selector.EntitySelector(
+                        selector.EntitySelectorConfig(domain=Platform.BINARY_SENSOR)
+                    ),
+                    vol.Optional(CONF_CIRCULATION_PUMP): selector.EntitySelector(
+                        selector.EntitySelectorConfig(domain=Platform.SWITCH)
+                    ),
+                    vol.Optional(CONF_PUMP_SCHEDULE): selector.EntitySelector(
+                        selector.EntitySelectorConfig()
+                    ),
+                }
+            ),
+        )
+
+    @staticmethod
+    @callback
+    def async_get_options_flow(config_entry: ConfigEntry) -> OptionsFlow:
+        """Get the options flow handler."""
+        return BoilerAuxHeaterOptionsFlow(config_entry)
+
+
+class BoilerAuxHeaterOptionsFlow(OptionsFlow):
+    """Handle options flow for Boiler Auxiliary Heater Control."""
+
+    def __init__(self, config_entry: ConfigEntry) -> None:
+        """Initialize options flow."""
+        self._config_entry = config_entry
+
+    async def async_step_init(
+        self, user_input: dict[str, Any] | None = None
+    ) -> dict:
+        """Manage entity references."""
+        if user_input is not None:
+            # Convert phase_count from string to int
+            if CONF_PHASE_COUNT in user_input:
+                user_input[CONF_PHASE_COUNT] = int(user_input[CONF_PHASE_COUNT])
+            return self.async_create_entry(title="", data=user_input)
+
+        current = {**self._config_entry.data, **self._config_entry.options}
+        current_phase_count = str(current.get(CONF_PHASE_COUNT, 3))
+
+        return self.async_show_form(
+            step_id="init",
+            data_schema=vol.Schema(
+                {
+                    vol.Required(
+                        CONF_BOILER_TEMP_SENSOR,
+                        default=current.get(CONF_BOILER_TEMP_SENSOR),
+                    ): selector.EntitySelector(
+                        selector.EntitySelectorConfig(
+                            domain=Platform.SENSOR,
+                            device_class=SensorDeviceClass.TEMPERATURE,
+                        )
+                    ),
+                    vol.Required(
+                        CONF_HEATER_RELAY,
+                        default=current.get(CONF_HEATER_RELAY),
+                    ): selector.EntitySelector(
+                        selector.EntitySelectorConfig(domain=Platform.SWITCH)
+                    ),
+                    vol.Required(
+                        CONF_PHASE_COUNT,
+                        default=current_phase_count,
+                    ): selector.SelectSelector(
+                        selector.SelectSelectorConfig(
+                            options=[
+                                selector.SelectOptionDict(value="1", label="1 Phase"),
+                                selector.SelectOptionDict(value="3", label="3 Phases"),
+                            ],
+                            mode=selector.SelectSelectorMode.DROPDOWN,
+                        )
+                    ),
+                    vol.Required(
+                        CONF_CT1_POWER,
+                        default=current.get(CONF_CT1_POWER),
+                    ): selector.EntitySelector(
+                        selector.EntitySelectorConfig(
+                            domain=Platform.SENSOR,
+                            device_class=SensorDeviceClass.POWER,
+                        )
+                    ),
+                    vol.Optional(
+                        CONF_CT2_POWER,
+                        description={
+                            "suggested_value": current.get(CONF_CT2_POWER)
+                        },
+                    ): selector.EntitySelector(
+                        selector.EntitySelectorConfig(
+                            domain=Platform.SENSOR,
+                            device_class=SensorDeviceClass.POWER,
+                        )
+                    ),
+                    vol.Optional(
+                        CONF_CT3_POWER,
+                        description={
+                            "suggested_value": current.get(CONF_CT3_POWER)
+                        },
+                    ): selector.EntitySelector(
+                        selector.EntitySelectorConfig(
+                            domain=Platform.SENSOR,
+                            device_class=SensorDeviceClass.POWER,
+                        )
+                    ),
+                    vol.Optional(
+                        CONF_HP_AUX_HEATER,
+                        description={
+                            "suggested_value": current.get(CONF_HP_AUX_HEATER)
+                        },
+                    ): selector.EntitySelector(
+                        selector.EntitySelectorConfig(domain=Platform.BINARY_SENSOR)
+                    ),
+                    vol.Optional(
+                        CONF_CIRCULATION_PUMP,
+                        description={
+                            "suggested_value": current.get(CONF_CIRCULATION_PUMP)
+                        },
+                    ): selector.EntitySelector(
+                        selector.EntitySelectorConfig(domain=Platform.SWITCH)
+                    ),
+                    vol.Optional(
+                        CONF_PUMP_SCHEDULE,
+                        description={
+                            "suggested_value": current.get(CONF_PUMP_SCHEDULE)
+                        },
+                    ): selector.EntitySelector(
+                        selector.EntitySelectorConfig()
+                    ),
+                }
+            ),
+        )
@@ -0,0 +1,228 @@
+"""Constants for the Boiler Auxiliary Heater Control integration."""
+
+DOMAIN = "boiler_aux_heater_3phase"
+MANUFACTURER = "Custom"
+
+# Config entry keys
+CONF_BOILER_TEMP_SENSOR = "boiler_temp_sensor"
+CONF_HEATER_RELAY = "heater_relay"
+CONF_CT1_POWER = "ct1_power"
+CONF_CT2_POWER = "ct2_power"
+CONF_CT3_POWER = "ct3_power"
+CONF_HP_AUX_HEATER = "hp_aux_heater"
+CONF_CIRCULATION_PUMP = "circulation_pump"
+CONF_PUMP_SCHEDULE = "pump_schedule"
+CONF_PHASE_COUNT = "phase_count"
+
+# Platforms
+PLATFORMS = [
+    "climate",
+    "switch",
+    "number",
+    "binary_sensor",
+    "sensor",
+    "button",
+]
+
+# Presets (order matters for UI)
+PRESET_NORMAL = "Normal"
+PRESET_ECO = "Eco"
+PRESET_BOOST = "Boost"
+PRESET_SLEEP = "Sleep"
+PRESET_AWAY = "Away"
+
+PRESETS = [PRESET_NORMAL, PRESET_ECO, PRESET_BOOST, PRESET_SLEEP, PRESET_AWAY]
+
+# PV state machine states
+PV_STATE_IDLE = "idle"
+PV_STATE_WAITING_START = "waiting_to_start"
+PV_STATE_ACTIVE = "active"
+PV_STATE_WAITING_STOP = "waiting_to_stop"
+
+# Number entity definitions: (key, name, min, max, step, unit, icon, default)
+NUMBER_DEFINITIONS = {
+    "cut_off_temp": {
+        "name": "Cut-off Temperature",
+        "min": 40,
+        "max": 85,
+        "step": 1,
+        "unit": "°C",
+        "icon": "mdi:thermometer-high",
+        "default": 60,
+    },
+    "temp_hysteresis": {
+        "name": "Temperature Hysteresis",
+        "min": 1,
+        "max": 15,
+        "step": 0.5,
+        "unit": "°C",
+        "icon": "mdi:thermometer-lines",
+        "default": 4,
+    },
+    "pv_target_temp": {
+        "name": "PV Target Temperature",
+        "min": 40,
+        "max": 70,
+        "step": 1,
+        "unit": "°C",
+        "icon": "mdi:solar-power",
+        "default": 55,
+    },
+    "pv_buffer": {
+        "name": "PV Excess Buffer",
+        "min": 0,
+        "max": 1000,
+        "step": 50,
+        "unit": "W",
+        "icon": "mdi:buffer",
+        "default": 100,
+    },
+    "heater_power": {
+        "name": "Heater Power Rating",
+        "min": 1500,
+        "max": 9000,
+        "step": 1500,
+        "unit": "W",
+        "icon": "mdi:lightning-bolt",
+        "default": 4500,
+    },
+    "pv_start_delay": {
+        "name": "PV Excess Start Delay",
+        "min": 1,
+        "max": 300,
+        "step": 1,
+        "unit": "s",
+        "icon": "mdi:timer-play",
+        "default": 60,
+    },
+    "pv_stop_delay": {
+        "name": "PV Excess Stop Delay",
+        "min": 1,
+        "max": 300,
+        "step": 1,
+        "unit": "s",
+        "icon": "mdi:timer-stop",
+        "default": 60,
+    },
+    "temp_normal": {
+        "name": "Normal Preset Temperature",
+        "min": 30,
+        "max": 65,
+        "step": 1,
+        "unit": "°C",
+        "icon": "mdi:thermometer",
+        "default": 44,
+    },
+    "temp_eco": {
+        "name": "Eco Preset Temperature",
+        "min": 30,
+        "max": 60,
+        "step": 1,
+        "unit": "°C",
+        "icon": "mdi:leaf",
+        "default": 40,
+    },
+    "temp_boost": {
+        "name": "Boost Preset Temperature",
+        "min": 40,
+        "max": 70,
+        "step": 1,
+        "unit": "°C",
+        "icon": "mdi:flash",
+        "default": 50,
+    },
+    "temp_sleep": {
+        "name": "Sleep Preset Temperature",
+        "min": 25,
+        "max": 55,
+        "step": 1,
+        "unit": "°C",
+        "icon": "mdi:sleep",
+        "default": 38,
+    },
+    "temp_away": {
+        "name": "Away Preset Temperature",
+        "min": 20,
+        "max": 50,
+        "step": 1,
+        "unit": "°C",
+        "icon": "mdi:home-export-outline",
+        "default": 35,
+    },
+    "bath_boost_duration": {
+        "name": "Bath Boost Duration",
+        "min": 5,
+        "max": 120,
+        "step": 5,
+        "unit": "min",
+        "icon": "mdi:timer-sand",
+        "default": 30,
+    },
+    "boost_all_modes_hysteresis": {
+        "name": "All Modes Boost Hysteresis",
+        "min": 3,
+        "max": 20,
+        "step": 1,
+        "unit": "°C",
+        "icon": "mdi:thermometer-alert",
+        "default": 10,
+    },
+    "boost_recovery_offset": {
+        "name": "Boost Recovery Offset",
+        "min": 0,
+        "max": 15,
+        "step": 1,
+        "unit": "°C",
+        "icon": "mdi:thermometer-minus",
+        "default": 3,
+    },
+}
+
+# Map preset name to number entity key
+PRESET_TEMP_MAP = {
+    PRESET_NORMAL: "temp_normal",
+    PRESET_ECO: "temp_eco",
+    PRESET_BOOST: "temp_boost",
+    PRESET_SLEEP: "temp_sleep",
+    PRESET_AWAY: "temp_away",
+}
+
+# Switch entity definitions: (key, name, icon, default)
+SWITCH_DEFINITIONS = {
+    "manual_override": {
+        "name": "Manual Override",
+        "icon": "mdi:water-boiler",
+        "default": False,
+    },
+    "allow_usage": {
+        "name": "Allow Aux Heater Usage",
+        "icon": "mdi:check-circle",
+        "default": True,
+    },
+    "pv_excess_mode": {
+        "name": "PV Excess Mode",
+        "icon": "mdi:solar-power",
+        "default": True,
+    },
+    "boost_all_modes": {
+        "name": "Boost in All Modes",
+        "icon": "mdi:thermostat",
+        "default": False,
+    },
+}
+
+# Thermostat tolerances (matching YAML)
+MAIN_COLD_TOLERANCE = 4.0
+MAIN_HOT_TOLERANCE = 0.0
+PV_COLD_TOLERANCE = 1.0
+PV_HOT_TOLERANCE = 0.5
+
+# Coordinator debounce
+DEBOUNCE_SECONDS = 1.0
+
+# Energy update interval (seconds) for steady-state accumulation
+ENERGY_UPDATE_INTERVAL = 60
+
+# Storage
+STORAGE_KEY = f"{DOMAIN}_boost_state"
+STORAGE_VERSION = 1
@@ -0,0 +1,713 @@
+"""Coordinator for Boiler Auxiliary Heater Control."""
+
+from __future__ import annotations
+
+import logging
+import time
+from datetime import datetime, timedelta, timezone
+from typing import Any
+
+from homeassistant.const import STATE_ON, STATE_UNAVAILABLE, STATE_UNKNOWN
+from homeassistant.core import CALLBACK_TYPE, Event, HomeAssistant, callback
+from homeassistant.helpers.event import (
+    async_call_later,
+    async_track_state_change_event,
+    async_track_time_interval,
+)
+from homeassistant.helpers.storage import Store
+
+from .const import (
+    CONF_BOILER_TEMP_SENSOR,
+    CONF_CIRCULATION_PUMP,
+    CONF_CT1_POWER,
+    CONF_CT2_POWER,
+    CONF_CT3_POWER,
+    CONF_HEATER_RELAY,
+    CONF_HP_AUX_HEATER,
+    CONF_PHASE_COUNT,
+    CONF_PUMP_SCHEDULE,
+    DEBOUNCE_SECONDS,
+    DOMAIN,
+    ENERGY_UPDATE_INTERVAL,
+    MAIN_COLD_TOLERANCE,
+    MAIN_HOT_TOLERANCE,
+    PRESET_BOOST,
+    PRESET_NORMAL,
+    PV_COLD_TOLERANCE,
+    PV_HOT_TOLERANCE,
+    PV_STATE_ACTIVE,
+    PV_STATE_IDLE,
+    PV_STATE_WAITING_START,
+    PV_STATE_WAITING_STOP,
+    STORAGE_KEY,
+    STORAGE_VERSION,
+)
+
+_LOGGER = logging.getLogger(__name__)
+
+
+class BoilerAuxHeaterCoordinator:
+    """Central coordinator for all boiler aux heater logic."""
+
+    def __init__(self, hass: HomeAssistant, config: dict[str, Any]) -> None:
+        """Initialize the coordinator."""
+        self.hass = hass
+        self.config = config
+
+        # External entity IDs
+        self.boiler_temp_sensor: str = config[CONF_BOILER_TEMP_SENSOR]
+        self.heater_relay: str = config[CONF_HEATER_RELAY]
+        self.ct1_power: str = config[CONF_CT1_POWER]
+        self.ct2_power: str | None = config.get(CONF_CT2_POWER)
+        self.ct3_power: str | None = config.get(CONF_CT3_POWER)
+        self.hp_aux_heater: str | None = config.get(CONF_HP_AUX_HEATER)
+        self.circulation_pump: str | None = config.get(CONF_CIRCULATION_PUMP)
+        self.pump_schedule: str | None = config.get(CONF_PUMP_SCHEDULE)
+        self.phase_count: int = config.get(CONF_PHASE_COUNT, 3)
+
+        # Internal entity references (set during platform setup)
+        self._number_entities: dict[str, Any] = {}
+        self._switch_entities: dict[str, Any] = {}
+        self._climate_entity: Any = None
+
+        # State
+        self.pv_state: str = PV_STATE_IDLE
+        self.bath_boost_active: bool = False
+        self._main_thermostat_heating: bool = False
+        self._all_modes_heating_demand: bool = False
+        self._bath_boost_timer_handle: CALLBACK_TYPE | None = None
+        self._bath_boost_remaining: float = 0
+        self._bath_boost_end_time: float | None = None
+        self._pre_boost_preset: str | None = None
+        self._pv_delay_handle: CALLBACK_TYPE | None = None
+        self._debounce_handle: CALLBACK_TYPE | None = None
+        self._energy_interval_unsub: CALLBACK_TYPE | None = None
+        self._min_cycle_deferred_handle: CALLBACK_TYPE | None = None
+
+        # Relay cycle protection (B6)
+        self._last_relay_change_time: float = 0.0
+
+        # Computed states (updated by recalculate)
+        self.decision: bool = False
+        self.decision_reason: str = "OFF: Initializing"
+        self.pv_sufficient: bool = False
+        self.relay_is_on: bool = False
+        self.pv_shadow_heating: bool = False
+
+        # Listeners
+        self._unsub_listeners: list[CALLBACK_TYPE] = []
+        self._update_callbacks: list[callback] = []
+
+        # Persistent storage (B4)
+        self._store = Store(hass, STORAGE_VERSION, STORAGE_KEY)
+
+    def register_number(self, key: str, entity: Any) -> None:
+        """Register a number entity for value lookups."""
+        self._number_entities[key] = entity
+
+    def register_switch(self, key: str, entity: Any) -> None:
+        """Register a switch entity for state lookups."""
+        self._switch_entities[key] = entity
+
+    def register_climate(self, entity: Any) -> None:
+        """Register the climate entity."""
+        self._climate_entity = entity
+
+    def get_number_value(self, key: str) -> float | None:
+        """Get current value of a number entity."""
+        entity = self._number_entities.get(key)
+        if entity is not None and entity.native_value is not None:
+            return float(entity.native_value)
+        return None
+
+    def get_switch_state(self, key: str) -> bool:
+        """Get current state of a switch entity."""
+        entity = self._switch_entities.get(key)
+        if entity is not None:
+            return entity.is_on
+        return False
+
+    @callback
+    def async_add_listener(self, update_callback: callback) -> CALLBACK_TYPE:
+        """Add a listener for coordinator updates."""
+        self._update_callbacks.append(update_callback)
+
+        @callback
+        def remove_listener() -> None:
+            self._update_callbacks.remove(update_callback)
+
+        return remove_listener
+
+    @callback
+    def _notify_listeners(self) -> None:
+        """Notify all registered listeners."""
+        for cb in self._update_callbacks:
+            cb()
+
+    async def async_setup(self) -> None:
+        """Set up state listeners on external entities."""
+        tracked = [
+            self.boiler_temp_sensor,
+            self.heater_relay,
+            self.ct1_power,
+        ]
+        if self.ct2_power:
+            tracked.append(self.ct2_power)
+        if self.ct3_power:
+            tracked.append(self.ct3_power)
+        if self.hp_aux_heater:
+            tracked.append(self.hp_aux_heater)
+
+        self._unsub_listeners.append(
+            async_track_state_change_event(
+                self.hass, tracked, self._async_state_changed
+            )
+        )
+
+        # B5: Periodic energy update every 60s for steady-state accumulation
+        self._energy_interval_unsub = async_track_time_interval(
+            self.hass,
+            self._async_energy_tick,
+            timedelta(seconds=ENERGY_UPDATE_INTERVAL),
+        )
+
+        # B4: Restore persisted boost state
+        await self._async_restore_boost_state()
+
+    async def _async_restore_boost_state(self) -> None:
+        """Restore bath boost state from storage after HA restart."""
+        data = await self._store.async_load()
+        if not data or not data.get("bath_boost_active"):
+            return
+
+        end_time_str = data.get("bath_boost_end_time")
+        if not end_time_str:
+            return
+
+        try:
+            end_time = datetime.fromisoformat(end_time_str)
+        except (ValueError, TypeError):
+            _LOGGER.warning("Invalid stored boost end time, cleaning up")
+            await self._async_clear_boost_storage()
+            return
+
+        now = datetime.now(timezone.utc)
+        remaining = (end_time - now).total_seconds()
+
+        self._pre_boost_preset = data.get("pre_boost_preset")
+
+        if remaining <= 0:
+            # Boost expired while HA was down - run cleanup
+            _LOGGER.info("Bath boost expired during downtime, running cleanup")
+            self._bath_boost_finished()
+        else:
+            # Resume boost with remaining time
+            _LOGGER.info(
+                "Resuming bath boost with %.0f seconds remaining", remaining
+            )
+            self.bath_boost_active = True
+            self._bath_boost_end_time = time.monotonic() + remaining
+            self._bath_boost_remaining = remaining
+            self._bath_boost_timer_handle = async_call_later(
+                self.hass, remaining, self._bath_boost_finished
+            )
+
+    async def _async_persist_boost_state(self) -> None:
+        """Save bath boost state to storage."""
+        if self.bath_boost_active and self._bath_boost_end_time is not None:
+            remaining = self._bath_boost_end_time - time.monotonic()
+            end_time_utc = datetime.now(timezone.utc) + timedelta(seconds=remaining)
+            await self._store.async_save(
+                {
+                    "bath_boost_active": True,
+                    "bath_boost_end_time": end_time_utc.isoformat(),
+                    "pre_boost_preset": self._pre_boost_preset,
+                }
+            )
+        else:
+            await self._async_clear_boost_storage()
+
+    async def _async_clear_boost_storage(self) -> None:
+        """Clear persisted boost state."""
+        await self._store.async_save(
+            {
+                "bath_boost_active": False,
+                "bath_boost_end_time": None,
+                "pre_boost_preset": None,
+            }
+        )
+
+    async def async_shutdown(self) -> None:
+        """Clean up all listeners and timers (full shutdown for unload)."""
+        self._async_shutdown_listeners()
+        if self._pv_delay_handle:
+            self._pv_delay_handle()
+            self._pv_delay_handle = None
+        if self._bath_boost_timer_handle:
+            self._bath_boost_timer_handle()
+            self._bath_boost_timer_handle = None
+        if self._debounce_handle:
+            self._debounce_handle()
+            self._debounce_handle = None
+        if self._min_cycle_deferred_handle:
+            self._min_cycle_deferred_handle()
+            self._min_cycle_deferred_handle = None
+
+    @callback
+    def _async_shutdown_listeners(self) -> None:
+        """Shut down only external entity listeners (B8: safe for options update)."""
+        for unsub in self._unsub_listeners:
+            unsub()
+        self._unsub_listeners.clear()
+        if self._energy_interval_unsub:
+            self._energy_interval_unsub()
+            self._energy_interval_unsub = None
+
+    @callback
+    def _async_state_changed(self, event: Event) -> None:
+        """Handle external state changes with debounce."""
+        if self._debounce_handle:
+            self._debounce_handle()
+        self._debounce_handle = async_call_later(
+            self.hass, DEBOUNCE_SECONDS, self._async_debounced_update
+        )
+
+    @callback
+    def _async_debounced_update(self, _now: Any = None) -> None:
+        """Run the full recalculation after debounce."""
+        self._debounce_handle = None
+        self._recalculate()
+
+    @callback
+    def _async_energy_tick(self, _now: Any = None) -> None:
+        """Periodic tick to ensure energy sensors accumulate during steady state (B5)."""
+        self._notify_listeners()
+
+    @callback
+    def async_request_refresh(self) -> None:
+        """Request an immediate recalculation (called by internal entities)."""
+        self._recalculate()
+
+    def _get_external_state(self, entity_id: str, default: str = "") -> str:
+        """Get external entity state safely."""
+        state = self.hass.states.get(entity_id)
+        if state is None or state.state in (STATE_UNAVAILABLE, STATE_UNKNOWN):
+            return default
+        return state.state
+
+    def _is_external_unavailable(self, entity_id: str) -> bool:
+        """Check if an external entity is unavailable or unknown."""
+        state = self.hass.states.get(entity_id)
+        return state is None or state.state in (STATE_UNAVAILABLE, STATE_UNKNOWN)
+
+    def _get_external_float(self, entity_id: str, default: float) -> float:
+        """Get external entity state as float with fallback."""
+        raw = self._get_external_state(entity_id)
+        if not raw:
+            return default
+        try:
+            return float(raw)
+        except (ValueError, TypeError):
+            return default
+
+    def _recalculate(self) -> None:
+        """Recalculate all derived states."""
+        # Read external states
+        boiler_temp = self._get_external_float(self.boiler_temp_sensor, 100.0)
+        relay_on = self._get_external_state(self.heater_relay) == STATE_ON
+
+        ct1 = self._get_external_float(self.ct1_power, 0.0)
+        ct2 = self._get_external_float(self.ct2_power, 0.0) if self.ct2_power else 0.0
+        ct3 = self._get_external_float(self.ct3_power, 0.0) if self.ct3_power else 0.0
+
+        # B1: HP aux heater interlock - default to True (ON) when unavailable (SAFETY)
+        hp_aux_on = False
+        hp_aux_unavailable = False
+        if self.hp_aux_heater:
+            if self._is_external_unavailable(self.hp_aux_heater):
+                hp_aux_on = True
+                hp_aux_unavailable = True
+                _LOGGER.warning(
+                    "HP aux heater sensor %s is unavailable - assuming ON for safety interlock",
+                    self.hp_aux_heater,
+                )
+            else:
+                hp_aux_on = self._get_external_state(self.hp_aux_heater) == STATE_ON
+
+        # Read internal settings
+        cut_off_temp = self.get_number_value("cut_off_temp") or 60.0
+        pv_buffer = self.get_number_value("pv_buffer") or 300.0
+        heater_power = self.get_number_value("heater_power") or 3000.0
+        pv_target_temp = self.get_number_value("pv_target_temp") or 55.0
+
+        manual_override = self.get_switch_state("manual_override")
+        allow_usage = self.get_switch_state("allow_usage")
+        pv_excess_mode = self.get_switch_state("pv_excess_mode")
+        boost_all_modes = self.get_switch_state("boost_all_modes")
+
+        self.relay_is_on = relay_on
+
+        # U2: PV sufficient calculation with configurable phase count
+        phases = self.phase_count
+        phase_buffer = pv_buffer / float(phases)
+        phase_heater = heater_power / float(phases)
+        turn_on_threshold = -1.0 * (phase_buffer + phase_heater)
+
+        if relay_on:
+            if phases == 1:
+                self.pv_sufficient = ct1 <= 0
+            else:
+                self.pv_sufficient = ct1 <= 0 and ct2 <= 0 and ct3 <= 0
+        else:
+            if phases == 1:
+                self.pv_sufficient = ct1 < turn_on_threshold
+            else:
+                self.pv_sufficient = (
+                    ct1 < turn_on_threshold
+                    and ct2 < turn_on_threshold
+                    and ct3 < turn_on_threshold
+                )
+
+        cold_tolerance = self.get_number_value("temp_hysteresis") or MAIN_COLD_TOLERANCE
+
+        # PV shadow thermostat logic
+        if not (pv_excess_mode and self.pv_state in (PV_STATE_ACTIVE, PV_STATE_WAITING_STOP)):
+            self.pv_shadow_heating = False
+        else:
+            # Shadow thermostat: is boiler temp below PV target (with tolerance)?
+            if boiler_temp < (pv_target_temp - cold_tolerance):
+                self.pv_shadow_heating = True
+            elif boiler_temp >= (pv_target_temp + PV_HOT_TOLERANCE):
+                self.pv_shadow_heating = False
+            # else: in the tolerance band - maintain previous state
+
+        # PV state machine transitions
+        self._update_pv_state_machine(pv_excess_mode)
+
+        # B7: Main thermostat heating check - use configurable hysteresis
+
+        if self._climate_entity is not None:
+            target = self._climate_entity.target_temperature
+            if target is not None and self._climate_entity.hvac_mode == "heat":
+                if boiler_temp < (target - cold_tolerance):
+                    self._main_thermostat_heating = True
+                elif boiler_temp >= (target + MAIN_HOT_TOLERANCE):
+                    self._main_thermostat_heating = False
+                # else: in tolerance band, maintain previous state
+            else:
+                self._main_thermostat_heating = False
+        else:
+            self._main_thermostat_heating = False
+        main_thermostat_heating = self._main_thermostat_heating
+
+        # All-modes heating demand: separate, larger hysteresis + recovery offset
+        boost_am_hysteresis = self.get_number_value("boost_all_modes_hysteresis") or 10.0
+        boost_recovery = self.get_number_value("boost_recovery_offset") or 3.0
+        if self._climate_entity is not None:
+            target_am = self._climate_entity.target_temperature
+            if target_am is not None and self._climate_entity.hvac_mode == "heat":
+                if boiler_temp < (target_am - boost_am_hysteresis):
+                    self._all_modes_heating_demand = True
+                elif boiler_temp >= (target_am - boost_recovery):
+                    self._all_modes_heating_demand = False
+                # else: in band, maintain previous state
+            else:
+                self._all_modes_heating_demand = False
+        else:
+            self._all_modes_heating_demand = False
+
+        # Boost conditions
+        bath_boost_heating = (
+            self.bath_boost_active and main_thermostat_heating
+        )
+        all_modes_heating = boost_all_modes and self._all_modes_heating_demand
+
+        # PV excess condition
+        pv_heating = pv_excess_mode and self.pv_shadow_heating
+
+        # Safety checks
+        boiler_temp_ok = boiler_temp < cut_off_temp
+        hp_aux_off = not hp_aux_on
+        allowed = hp_aux_off and allow_usage and boiler_temp_ok
+
+        # F1: Compute decision reason
+        old_decision = self.decision
+        if manual_override:
+            self.decision = True
+            self.decision_reason = "Manual override"
+        elif not allow_usage:
+            self.decision = False
+            self.decision_reason = "OFF: Disabled by user"
+        elif hp_aux_unavailable:
+            self.decision = False
+            self.decision_reason = "OFF: HP aux heater sensor unavailable (safety)"
+        elif hp_aux_on:
+            self.decision = False
+            self.decision_reason = "OFF: HP aux heater active"
+        elif not boiler_temp_ok:
+            self.decision = False
+            self.decision_reason = f"OFF: Temperature above cut-off ({cut_off_temp:.0f}\u00b0C)"
+        elif self._climate_entity is not None and self._climate_entity.hvac_mode == "off":
+            self.decision = False
+            self.decision_reason = "OFF: HVAC mode off"
+        elif pv_heating:
+            self.decision = True
+            self.decision_reason = "PV excess heating"
+        elif bath_boost_heating:
+            self.decision = True
+            self.decision_reason = "Bath boost heating"
+        elif all_modes_heating:
+            self.decision = True
+            self.decision_reason = "All modes boost heating"
+        else:
+            self.decision = False
+            self.decision_reason = "OFF: No heating demand"
+
+        if self.decision != old_decision:
+            self.hass.async_create_task(self._async_control_relay(self.decision))
+
+        self._notify_listeners()
+
+    @callback
+    def _async_min_cycle_recheck(self, _now: Any = None) -> None:
+        """Re-check decision after min cycle duration elapsed."""
+        self._min_cycle_deferred_handle = None
+        self._recalculate()
+
+    def _update_pv_state_machine(self, pv_enabled: bool) -> None:
+        """Update PV excess state machine based on pv_sufficient."""
+        if not pv_enabled:
+            if self.pv_state != PV_STATE_IDLE:
+                self._cancel_pv_delay()
+                self.pv_state = PV_STATE_IDLE
+                self.pv_shadow_heating = False
+            return
+
+        if self.pv_sufficient and self.pv_state == PV_STATE_IDLE:
+            # Start waiting to activate
+            self.pv_state = PV_STATE_WAITING_START
+            start_delay = self.get_number_value("pv_start_delay") or 60.0
+            self._cancel_pv_delay()
+            self._pv_delay_handle = async_call_later(
+                self.hass, start_delay, self._pv_start_callback
+            )
+
+        elif not self.pv_sufficient and self.pv_state == PV_STATE_WAITING_START:
+            # PV dropped before delay elapsed, cancel
+            self._cancel_pv_delay()
+            self.pv_state = PV_STATE_IDLE
+
+        elif not self.pv_sufficient and self.pv_state == PV_STATE_ACTIVE:
+            # Start waiting to deactivate
+            self.pv_state = PV_STATE_WAITING_STOP
+            stop_delay = self.get_number_value("pv_stop_delay") or 60.0
+            self._cancel_pv_delay()
+            self._pv_delay_handle = async_call_later(
+                self.hass, stop_delay, self._pv_stop_callback
+            )
+
+        elif self.pv_sufficient and self.pv_state == PV_STATE_WAITING_STOP:
+            # PV recovered before stop delay, cancel stop
+            self._cancel_pv_delay()
+            self.pv_state = PV_STATE_ACTIVE
+
+    @callback
+    def _pv_start_callback(self, _now: Any = None) -> None:
+        """PV start delay elapsed - activate PV mode."""
+        self._pv_delay_handle = None
+        if self.pv_sufficient:
+            self.pv_state = PV_STATE_ACTIVE
+            self._recalculate()
+        else:
+            self.pv_state = PV_STATE_IDLE
+
+    @callback
+    def _pv_stop_callback(self, _now: Any = None) -> None:
+        """PV stop delay elapsed - deactivate PV mode."""
+        self._pv_delay_handle = None
+        self.pv_state = PV_STATE_IDLE
+        self.pv_shadow_heating = False
+        self._recalculate()
+
+    def _cancel_pv_delay(self) -> None:
+        """Cancel any pending PV delay timer."""
+        if self._pv_delay_handle:
+            self._pv_delay_handle()
+            self._pv_delay_handle = None
+
+    async def _async_control_relay(self, turn_on: bool) -> None:
+        """Control the physical heater relay."""
+        try:
+            await self.hass.services.async_call(
+                "switch",
+                "turn_on" if turn_on else "turn_off",
+                {"entity_id": self.heater_relay},
+            )
+        except Exception:
+            _LOGGER.exception("Failed to control heater relay %s", self.heater_relay)
+
+    # Bath boost management
+
+    async def async_start_bath_boost(self) -> None:
+        """Start the bath boost timer."""
+        duration_min = self.get_number_value("bath_boost_duration") or 30.0
+        duration_sec = duration_min * 60
+
+        # B3: Store pre-boost preset for later restoration.
+        # Only capture if not already pre-set by climate entity to avoid reading
+        # the already-changed "Boost" value when called from async_set_preset_mode.
+        if self._climate_entity is not None and self._pre_boost_preset is None:
+            self._pre_boost_preset = self._climate_entity.preset_mode
+
+        # Turn on circulation pump if configured
+        if self.circulation_pump:
+            try:
+                await self.hass.services.async_call(
+                    "switch",
+                    "turn_on",
+                    {"entity_id": self.circulation_pump},
+                )
+            except Exception:
+                _LOGGER.exception("Failed to turn on circulation pump")
+
+        # Activate bath boost
+        self.bath_boost_active = True
+
+        # Set preset to Boost on climate entity
+        if self._climate_entity is not None:
+            await self._climate_entity.async_set_preset_mode(PRESET_BOOST)
+
+        # Start countdown timer
+        self._bath_boost_end_time = time.monotonic() + duration_sec
+        self._bath_boost_remaining = duration_sec
+
+        if self._bath_boost_timer_handle:
+            self._bath_boost_timer_handle()
+        self._bath_boost_timer_handle = async_call_later(
+            self.hass, duration_sec, self._bath_boost_finished
+        )
+
+        # B4: Persist boost state
+        await self._async_persist_boost_state()
+
+        self._recalculate()
+
+    async def async_stop_bath_boost(self, restore_preset: bool = True) -> None:
+        """Stop the bath boost (cancel button / preset change / cleanup)."""
+        if self._bath_boost_timer_handle:
+            self._bath_boost_timer_handle()
+            self._bath_boost_timer_handle = None
+
+        self._bath_boost_end_time = None
+        self._bath_boost_remaining = 0
+        self.bath_boost_active = False
+
+        # Restore pump schedule if configured
+        if self.pump_schedule:
+            await self._async_restore_pump_schedule()
+
+        # Turn off circulation pump if configured
+        if self.circulation_pump:
+            try:
+                await self.hass.services.async_call(
+                    "switch",
+                    "turn_off",
+                    {"entity_id": self.circulation_pump},
+                )
+            except Exception:
+                _LOGGER.exception("Failed to turn off circulation pump")
+
+        # B3: Restore pre-boost preset (only when not called from a user preset change;
+        # when restore_preset=False the climate entity already shows the correct new preset)
+        preset_to_restore = self._pre_boost_preset or PRESET_NORMAL
+        self._pre_boost_preset = None
+        if restore_preset and self._climate_entity is not None:
+            await self._climate_entity.async_set_preset_mode(preset_to_restore)
+
+        # B4: Clear persisted state
+        await self._async_clear_boost_storage()
+
+        self._recalculate()
+
+    @callback
+    def _bath_boost_finished(self, _now: Any = None) -> None:
+        """Bath boost timer expired."""
+        self._bath_boost_timer_handle = None
+        self._bath_boost_end_time = None
+        self._bath_boost_remaining = 0
+        self.bath_boost_active = False
+
+        # Capture duration for event before clearing state
+        duration_min = self.get_number_value("bath_boost_duration") or 30.0
+        pre_preset = self._pre_boost_preset
+
+        # Restore pump schedule if configured
+        if self.pump_schedule:
+            self.hass.async_create_task(self._async_restore_pump_schedule())
+
+        # Turn off circulation pump if configured
+        if self.circulation_pump:
+            self.hass.async_create_task(
+                self.hass.services.async_call(
+                    "switch",
+                    "turn_off",
+                    {"entity_id": self.circulation_pump},
+                )
+            )
+
+        # B3: Restore pre-boost preset
+        restore_preset = self._pre_boost_preset or PRESET_NORMAL
+        self._pre_boost_preset = None
+        if self._climate_entity is not None:
+            self.hass.async_create_task(
+                self._climate_entity.async_set_preset_mode(restore_preset)
+            )
+
+        # B4: Clear persisted state
+        self.hass.async_create_task(self._async_clear_boost_storage())
+
+        # U3: Fire HA event on boost finish
+        self.hass.bus.async_fire(
+            f"{DOMAIN}_boost_finished",
+            {
+                "duration_minutes": duration_min,
+                "pre_boost_preset": pre_preset,
+                "restored_preset": restore_preset,
+            },
+        )
+
+        self._recalculate()
+
+    async def _async_restore_pump_schedule(self) -> None:
+        """Restore the pump schedule after bath boost."""
+        if not self.pump_schedule:
+            return
+        try:
+            await self.hass.services.async_call(
+                "scheduler",
+                "run_action",
+                {"entity_id": self.pump_schedule},
+            )
+        except Exception:
+            _LOGGER.warning("Failed to restore pump schedule %s", self.pump_schedule)
+
+    @property
+    def bath_boost_remaining_seconds(self) -> float:
+        """Get remaining bath boost time in seconds."""
+        if not self.bath_boost_active or self._bath_boost_end_time is None:
+            return 0
+        remaining = self._bath_boost_end_time - time.monotonic()
+        return max(0, remaining)
+
+    def update_config(self, new_config: dict[str, Any]) -> None:
+        """Update configuration (called from options flow)."""
+        self.config = new_config
+        self.boiler_temp_sensor = new_config[CONF_BOILER_TEMP_SENSOR]
+        self.heater_relay = new_config[CONF_HEATER_RELAY]
+        self.ct1_power = new_config[CONF_CT1_POWER]
+        self.ct2_power = new_config.get(CONF_CT2_POWER)
+        self.ct3_power = new_config.get(CONF_CT3_POWER)
+        self.hp_aux_heater = new_config.get(CONF_HP_AUX_HEATER)
+        self.circulation_pump = new_config.get(CONF_CIRCULATION_PUMP)
+        self.pump_schedule = new_config.get(CONF_PUMP_SCHEDULE)
+        self.phase_count = new_config.get(CONF_PHASE_COUNT, 3)
@@ -0,0 +1,389 @@
+views:
+  - title: Aux Heater Control
+    type: sections
+    max_columns: 4
+    icon: mdi:heating-coil
+    subview: false
+    path: aux-heater-control
+    header:
+      card:
+        type: markdown
+        content: |-
+          # Auxiliary Heater Control
+          Manage the boiler auxiliary heater, presets, PV excess, and bath boost
+        text_only: true
+    sections:
+      # ── Thermostat ──
+      - type: grid
+        column_span: 2
+        cards:
+          - type: heading
+            heading: Thermostat
+            heading_style: title
+            icon: mdi:thermometer
+          - type: thermostat
+            entity: climate.boiler_auxiliary_heater
+            features:
+              - type: climate-preset-modes
+                style: dropdown
+            show_current_as_primary: true
+            grid_options:
+              columns: full
+
+      # ── Boost ──
+      - type: grid
+        column_span: 2
+        cards:
+          - type: heading
+            heading: Bath Boost
+            heading_style: title
+            icon: mdi:rocket-launch
+          - type: tile
+            entity: button.boiler_auxiliary_heater_start_bath_boost
+            vertical: false
+            state_content: last_changed
+            tap_action:
+              action: call-service
+              service: button.press
+              target:
+                entity_id: button.boiler_auxiliary_heater_start_bath_boost
+            grid_options:
+              columns: full
+              rows: 2
+          - type: tile
+            entity: button.boiler_auxiliary_heater_cancel_bath_boost
+            vertical: false
+            state_content: last_changed
+            tap_action:
+              action: call-service
+              service: button.press
+              target:
+                entity_id: button.boiler_auxiliary_heater_cancel_bath_boost
+            grid_options:
+              columns: full
+              rows: 2
+          - type: tile
+            entity: binary_sensor.boiler_auxiliary_heater_bath_boost_active
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - type: tile
+            entity: sensor.boiler_auxiliary_heater_bath_boost_remaining
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_bath_boost_duration
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+
+      # ── Configuration: Switches ──
+      - type: grid
+        column_span: 2
+        cards:
+          - type: heading
+            heading: Mode Switches
+            heading_style: title
+            icon: mdi:toggle-switch
+          - features:
+              - type: toggle
+            type: tile
+            entity: switch.boiler_auxiliary_heater_allow_aux_heater_usage
+            features_position: bottom
+            vertical: false
+            state_content: last_changed
+            grid_options:
+              columns: full
+          - features:
+              - type: toggle
+            type: tile
+            entity: switch.boiler_auxiliary_heater_manual_override
+            features_position: bottom
+            vertical: false
+            state_content: last_changed
+            grid_options:
+              columns: full
+          - features:
+              - type: toggle
+            type: tile
+            entity: switch.boiler_auxiliary_heater_pv_excess_mode
+            features_position: bottom
+            vertical: false
+            state_content: last_changed
+            grid_options:
+              columns: full
+          - features:
+              - type: toggle
+            type: tile
+            entity: switch.boiler_auxiliary_heater_boost_in_all_modes
+            features_position: bottom
+            vertical: false
+            state_content: last_changed
+            grid_options:
+              columns: full
+
+      # ── Configuration: Temperature Presets ──
+      - type: grid
+        column_span: 2
+        cards:
+          - type: heading
+            heading: Preset Temperatures
+            heading_style: title
+            icon: mdi:thermometer-lines
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_normal_preset_temperature
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_eco_preset_temperature
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_boost_preset_temperature
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_sleep_preset_temperature
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_away_preset_temperature
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+
+      # ── Configuration: Safety & Heater Settings ──
+      - type: grid
+        column_span: 2
+        cards:
+          - type: heading
+            heading: Safety & Heater Settings
+            heading_style: title
+            icon: mdi:shield-check
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_cut_off_temperature
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_temperature_hysteresis
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_heater_power_rating
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_all_modes_boost_hysteresis
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_boost_recovery_offset
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+
+      # ── Configuration: PV Excess Settings ──
+      - type: grid
+        column_span: 2
+        cards:
+          - type: heading
+            heading: PV Excess Settings
+            heading_style: title
+            icon: mdi:solar-power-variant
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_pv_target_temperature
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_pv_excess_buffer
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_pv_excess_start_delay
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - features:
+              - type: numeric-input
+                style: buttons
+            type: tile
+            entity: number.boiler_auxiliary_heater_pv_excess_stop_delay
+            features_position: bottom
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+
+      # ── Status: Decision & PV State ──
+      - type: grid
+        column_span: 2
+        cards:
+          - type: heading
+            heading: Heater Status
+            heading_style: title
+            icon: mdi:information
+          - type: tile
+            entity: binary_sensor.boiler_auxiliary_heater_heater_decision
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - type: tile
+            entity: sensor.boiler_auxiliary_heater_decision_reason
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - type: tile
+            entity: sensor.boiler_auxiliary_heater_pv_state
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - type: tile
+            entity: binary_sensor.boiler_auxiliary_heater_pv_power_sufficient
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - type: tile
+            entity: binary_sensor.boiler_auxiliary_heater_running_on_pv
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - type: tile
+            entity: binary_sensor.boiler_auxiliary_heater_running_on_grid
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+
+      # ── Status: Power & Energy ──
+      - type: grid
+        column_span: 2
+        cards:
+          - type: heading
+            heading: Power & Energy
+            heading_style: title
+            icon: mdi:lightning-bolt
+          - type: tile
+            entity: sensor.boiler_auxiliary_heater_heater_power
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - type: tile
+            entity: sensor.boiler_auxiliary_heater_heater_pv_power
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - type: tile
+            entity: sensor.boiler_auxiliary_heater_heater_grid_power
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - type: tile
+            entity: sensor.boiler_auxiliary_heater_heater_energy
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - type: tile
+            entity: sensor.boiler_auxiliary_heater_heater_pv_energy
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+          - type: tile
+            entity: sensor.boiler_auxiliary_heater_heater_grid_energy
+            vertical: false
+            state_content: state
+            grid_options:
+              columns: full
+    cards: []
@@ -0,0 +1,12 @@
+{
+  "domain": "boiler_aux_heater_3phase",
+  "name": "Boiler Auxiliary Heater Control",
+  "codeowners": ["@costea32"],
+  "config_flow": true,
+  "dependencies": [],
+  "documentation": "https://github.com/costea32/ha-boiler-aux-heater-3phase",
+  "iot_class": "local_push",
+  "version": "1.0.0",
+  "requirements": [],
+  "homeassistant": "2024.1.0"
+}
@@ -0,0 +1,121 @@
+"""Number entities for Boiler Auxiliary Heater Control."""
+
+from __future__ import annotations
+
+from homeassistant.components.number import NumberEntity, NumberMode
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.const import EntityCategory
+from homeassistant.core import HomeAssistant, callback
+from homeassistant.helpers.entity import DeviceInfo
+from homeassistant.helpers.entity_platform import AddEntitiesCallback
+from homeassistant.helpers.restore_state import RestoreEntity
+
+from .const import DOMAIN, NUMBER_DEFINITIONS
+
+
+async def async_setup_entry(
+    hass: HomeAssistant,
+    entry: ConfigEntry,
+    async_add_entities: AddEntitiesCallback,
+) -> None:
+    """Set up number entities."""
+    coordinator = hass.data[DOMAIN][entry.entry_id]
+
+    entities = []
+    for key, defn in NUMBER_DEFINITIONS.items():
+        if key == "pv_target_temp":
+            entity = PvTargetTempNumber(coordinator, entry, key, defn)
+        else:
+            entity = BoilerAuxHeaterNumber(coordinator, entry, key, defn)
+        entities.append(entity)
+
+    async_add_entities(entities)
+
+
+class BoilerAuxHeaterNumber(RestoreEntity, NumberEntity):
+    """A configurable number parameter for the boiler aux heater."""
+
+    _attr_has_entity_name = True
+    _attr_mode = NumberMode.SLIDER
+    _attr_entity_category = EntityCategory.CONFIG
+
+    def __init__(
+        self,
+        coordinator,
+        entry: ConfigEntry,
+        key: str,
+        defn: dict,
+    ) -> None:
+        """Initialize the number entity."""
+        self.coordinator = coordinator
+        self._key = key
+        self._defn = defn
+        self._attr_unique_id = f"{entry.entry_id}_{key}"
+        self._attr_translation_key = key
+        self._attr_native_min_value = defn["min"]
+        self._attr_native_max_value = defn["max"]
+        self._attr_native_step = defn["step"]
+        self._attr_native_unit_of_measurement = defn["unit"]
+        self._attr_icon = defn["icon"]
+        self._attr_native_value = defn["default"]
+        self._attr_device_info = DeviceInfo(
+            identifiers={(DOMAIN, entry.entry_id)},
+            name="Boiler Auxiliary Heater",
+            manufacturer="Custom",
+        )
+
+    async def async_added_to_hass(self) -> None:
+        """Restore state on startup."""
+        await super().async_added_to_hass()
+        last_state = await self.async_get_last_state()
+        if last_state and last_state.state not in ("unknown", "unavailable"):
+            try:
+                self._attr_native_value = float(last_state.state)
+            except (ValueError, TypeError):
+                pass
+        # Register with coordinator
+        self.coordinator.register_number(self._key, self)
+
+    async def async_set_native_value(self, value: float) -> None:
+        """Set new value."""
+        self._attr_native_value = value
+        self.async_write_ha_state()
+        # Trigger coordinator recalculation
+        self.coordinator.async_request_refresh()
+
+
+class PvTargetTempNumber(BoilerAuxHeaterNumber):
+    """PV Target Temperature with dynamic max capped at cut_off_temp - 1."""
+
+    def __init__(self, coordinator, entry: ConfigEntry, key: str, defn: dict) -> None:
+        """Initialize."""
+        super().__init__(coordinator, entry, key, defn)
+        self._unsub_coordinator = None
+
+    async def async_added_to_hass(self) -> None:
+        """Restore state and subscribe to coordinator updates."""
+        await super().async_added_to_hass()
+        self._unsub_coordinator = self.coordinator.async_add_listener(
+            self._handle_coordinator_update
+        )
+
+    async def async_will_remove_from_hass(self) -> None:
+        """Clean up coordinator listener."""
+        if self._unsub_coordinator:
+            self._unsub_coordinator()
+
+    @callback
+    def _handle_coordinator_update(self) -> None:
+        """Clamp value to new max and update HA state."""
+        max_val = self.native_max_value
+        if self._attr_native_value is not None and self._attr_native_value > max_val:
+            self._attr_native_value = max_val
+        self.async_write_ha_state()
+
+    @property
+    def native_max_value(self) -> float:
+        """Return max value capped at cut_off_temp - 1."""
+        cut_off = self.coordinator.get_number_value("cut_off_temp")
+        if cut_off is not None:
+            return min(self._defn["max"], cut_off - 1)
+        return self._defn["max"]
@@ -0,0 +1,301 @@
+"""Sensor entities for Boiler Auxiliary Heater Control."""
+
+from __future__ import annotations
+
+import time
+
+from homeassistant.components.sensor import (
+    SensorDeviceClass,
+    SensorEntity,
+    SensorStateClass,
+)
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.const import UnitOfEnergy, UnitOfPower, UnitOfTime
+from homeassistant.core import HomeAssistant, callback
+from homeassistant.helpers.entity import DeviceInfo
+from homeassistant.helpers.entity_platform import AddEntitiesCallback
+from homeassistant.helpers.restore_state import RestoreEntity
+
+from .const import DOMAIN
+
+
+async def async_setup_entry(
+    hass: HomeAssistant,
+    entry: ConfigEntry,
+    async_add_entities: AddEntitiesCallback,
+) -> None:
+    """Set up sensor entities."""
+    coordinator = hass.data[DOMAIN][entry.entry_id]
+
+    entities: list[SensorEntity] = [
+        BoilerPowerSensor(coordinator, entry, "total_power", "Heater Power"),
+        BoilerPowerSensor(coordinator, entry, "pv_power", "Heater PV Power"),
+        BoilerPowerSensor(coordinator, entry, "grid_power", "Heater Grid Power"),
+        BoilerEnergySensor(coordinator, entry, "total_energy", "Heater Energy", "total_power"),
+        BoilerEnergySensor(coordinator, entry, "pv_energy", "Heater PV Energy", "pv_power"),
+        BoilerEnergySensor(coordinator, entry, "grid_energy", "Heater Grid Energy", "grid_power"),
+        BathBoostRemainingSensor(coordinator, entry),
+        DecisionReasonSensor(coordinator, entry),
+        PvStateSensor(coordinator, entry),
+    ]
+
+    async_add_entities(entities)
+
+
+class BoilerPowerSensor(SensorEntity):
+    """Power sensor that reports heater wattage based on relay/PV state."""
+
+    _attr_has_entity_name = True
+    _attr_device_class = SensorDeviceClass.POWER
+    _attr_state_class = SensorStateClass.MEASUREMENT
+    _attr_native_unit_of_measurement = UnitOfPower.WATT
+
+    def __init__(
+        self, coordinator, entry: ConfigEntry, key: str, name: str
+    ) -> None:
+        """Initialize the power sensor."""
+        self.coordinator = coordinator
+        self._key = key
+        self._attr_unique_id = f"{entry.entry_id}_{key}"
+        self._attr_translation_key = key
+        self._unsub_listener = None
+        self._attr_device_info = DeviceInfo(
+            identifiers={(DOMAIN, entry.entry_id)},
+            name="Boiler Auxiliary Heater",
+            manufacturer="Custom",
+        )
+
+    async def async_added_to_hass(self) -> None:
+        """Register with coordinator."""
+        self._unsub_listener = self.coordinator.async_add_listener(
+            self._handle_coordinator_update
+        )
+
+    async def async_will_remove_from_hass(self) -> None:
+        """Clean up."""
+        if self._unsub_listener:
+            self._unsub_listener()
+
+    @callback
+    def _handle_coordinator_update(self) -> None:
+        """Update on coordinator changes."""
+        self.async_write_ha_state()
+
+    @property
+    def native_value(self) -> float:
+        """Return power value."""
+        heater_power = self.coordinator.get_number_value("heater_power") or 0.0
+        relay_on = self.coordinator.relay_is_on
+        pv_sufficient = self.coordinator.pv_sufficient
+
+        if self._key == "total_power":
+            return heater_power if relay_on else 0.0
+        if self._key == "pv_power":
+            return heater_power if (relay_on and pv_sufficient) else 0.0
+        if self._key == "grid_power":
+            return heater_power if (relay_on and not pv_sufficient) else 0.0
+        return 0.0
+
+
+class BoilerEnergySensor(RestoreEntity, SensorEntity):
+    """Energy sensor using internal Riemann sum integration."""
+
+    _attr_has_entity_name = True
+    _attr_device_class = SensorDeviceClass.ENERGY
+    _attr_state_class = SensorStateClass.TOTAL_INCREASING
+    _attr_native_unit_of_measurement = UnitOfEnergy.KILO_WATT_HOUR
+
+    def __init__(
+        self,
+        coordinator,
+        entry: ConfigEntry,
+        key: str,
+        name: str,
+        power_key: str,
+    ) -> None:
+        """Initialize the energy sensor."""
+        self.coordinator = coordinator
+        self._key = key
+        self._power_key = power_key
+        self._attr_unique_id = f"{entry.entry_id}_{key}"
+        self._attr_translation_key = key
+        self._accumulated_energy: float = 0.0
+        self._last_update_time: float | None = None
+        self._unsub_listener = None
+        self._attr_device_info = DeviceInfo(
+            identifiers={(DOMAIN, entry.entry_id)},
+            name="Boiler Auxiliary Heater",
+            manufacturer="Custom",
+        )
+
+    async def async_added_to_hass(self) -> None:
+        """Restore accumulated energy and start tracking."""
+        await super().async_added_to_hass()
+        last_state = await self.async_get_last_state()
+        if last_state and last_state.state not in ("unknown", "unavailable"):
+            try:
+                self._accumulated_energy = float(last_state.state)
+            except (ValueError, TypeError):
+                pass
+
+        self._last_update_time = time.monotonic()
+        self._unsub_listener = self.coordinator.async_add_listener(
+            self._handle_coordinator_update
+        )
+
+    async def async_will_remove_from_hass(self) -> None:
+        """Clean up."""
+        if self._unsub_listener:
+            self._unsub_listener()
+
+    @callback
+    def _handle_coordinator_update(self) -> None:
+        """Integrate power over time on each update."""
+        now = time.monotonic()
+        if self._last_update_time is not None:
+            elapsed_hours = (now - self._last_update_time) / 3600.0
+            power_w = self._get_power_value()
+            self._accumulated_energy += (power_w / 1000.0) * elapsed_hours
+        self._last_update_time = now
+        self.async_write_ha_state()
+
+    def _get_power_value(self) -> float:
+        """Get the current power for integration."""
+        heater_power = self.coordinator.get_number_value("heater_power") or 0.0
+        relay_on = self.coordinator.relay_is_on
+        pv_sufficient = self.coordinator.pv_sufficient
+
+        if self._power_key == "total_power":
+            return heater_power if relay_on else 0.0
+        if self._power_key == "pv_power":
+            return heater_power if (relay_on and pv_sufficient) else 0.0
+        if self._power_key == "grid_power":
+            return heater_power if (relay_on and not pv_sufficient) else 0.0
+        return 0.0
+
+    @property
+    def native_value(self) -> float:
+        """Return accumulated energy in kWh."""
+        return round(self._accumulated_energy, 3)
+
+
+class BathBoostRemainingSensor(SensorEntity):
+    """Sensor showing remaining bath boost time."""
+
+    _attr_has_entity_name = True
+    _attr_translation_key = "bath_boost_remaining"
+    _attr_device_class = SensorDeviceClass.DURATION
+    _attr_native_unit_of_measurement = UnitOfTime.SECONDS
+    _attr_icon = "mdi:timer-sand"
+
+    def __init__(self, coordinator, entry: ConfigEntry) -> None:
+        """Initialize the bath boost remaining sensor."""
+        self.coordinator = coordinator
+        self._attr_unique_id = f"{entry.entry_id}_bath_boost_remaining"
+        self._unsub_listener = None
+        self._attr_device_info = DeviceInfo(
+            identifiers={(DOMAIN, entry.entry_id)},
+            name="Boiler Auxiliary Heater",
+            manufacturer="Custom",
+        )
+
+    async def async_added_to_hass(self) -> None:
+        """Register with coordinator."""
+        self._unsub_listener = self.coordinator.async_add_listener(
+            self._handle_coordinator_update
+        )
+
+    async def async_will_remove_from_hass(self) -> None:
+        """Clean up."""
+        if self._unsub_listener:
+            self._unsub_listener()
+
+    @callback
+    def _handle_coordinator_update(self) -> None:
+        """Update state."""
+        self.async_write_ha_state()
+
+    @property
+    def native_value(self) -> float:
+        """Return remaining seconds."""
+        return round(self.coordinator.bath_boost_remaining_seconds, 0)
+
+
+class DecisionReasonSensor(SensorEntity):
+    """Sensor reporting why the heater is ON or OFF (F1)."""
+
+    _attr_has_entity_name = True
+    _attr_translation_key = "decision_reason"
+    _attr_icon = "mdi:information-outline"
+
+    def __init__(self, coordinator, entry: ConfigEntry) -> None:
+        """Initialize the decision reason sensor."""
+        self.coordinator = coordinator
+        self._attr_unique_id = f"{entry.entry_id}_decision_reason"
+        self._unsub_listener = None
+        self._attr_device_info = DeviceInfo(
+            identifiers={(DOMAIN, entry.entry_id)},
+            name="Boiler Auxiliary Heater",
+            manufacturer="Custom",
+        )
+
+    async def async_added_to_hass(self) -> None:
+        """Register with coordinator."""
+        self._unsub_listener = self.coordinator.async_add_listener(
+            self._handle_coordinator_update
+        )
+
+    async def async_will_remove_from_hass(self) -> None:
+        """Clean up."""
+        if self._unsub_listener:
+            self._unsub_listener()
+
+    @callback
+    def _handle_coordinator_update(self) -> None:
+        """Update state."""
+        self.async_write_ha_state()
+
+    @property
+    def native_value(self) -> str:
+        """Return the decision reason text."""
+        return self.coordinator.decision_reason
+
+
+class PvStateSensor(SensorEntity):
+    """Sensor exposing the PV excess state machine state (F2)."""
+
+    _attr_has_entity_name = True
+    _attr_translation_key = "pv_state"
+    _attr_icon = "mdi:solar-power-variant"
+
+    def __init__(self, coordinator, entry: ConfigEntry) -> None:
+        """Initialize the PV state sensor."""
+        self.coordinator = coordinator
+        self._attr_unique_id = f"{entry.entry_id}_pv_state"
+        self._unsub_listener = None
+        self._attr_device_info = DeviceInfo(
+            identifiers={(DOMAIN, entry.entry_id)},
+            name="Boiler Auxiliary Heater",
+            manufacturer="Custom",
+        )
+
+    async def async_added_to_hass(self) -> None:
+        """Register with coordinator."""
+        self._unsub_listener = self.coordinator.async_add_listener(
+            self._handle_coordinator_update
+        )
+
+    async def async_will_remove_from_hass(self) -> None:
+        """Clean up."""
+        if self._unsub_listener:
+            self._unsub_listener()
+
+    @callback
+    def _handle_coordinator_update(self) -> None:
+        """Update state."""
+        self.async_write_ha_state()
+
+    @property
+    def native_value(self) -> str:
+        """Return the PV state machine state."""
+        return self.coordinator.pv_state
@@ -0,0 +1,11 @@
+start_bath_boost:
+  name: Start Bath Boost
+  description: >-
+    Starts the bath boost timer with the configured duration.
+    Turns on the circulation pump and sets the thermostat to Boost preset.
+
+stop_bath_boost:
+  name: Stop Bath Boost
+  description: >-
+    Stops an active bath boost. Cancels the timer, turns off the circulation
+    pump, restores the pump schedule, and restores the previous preset.
@@ -0,0 +1,187 @@
+{
+  "config": {
+    "step": {
+      "user": {
+        "title": "Core Hardware",
+        "description": "Select the boiler temperature sensor and heater relay switch.",
+        "data": {
+          "boiler_temp_sensor": "Boiler temperature sensor",
+          "heater_relay": "Heater relay switch"
+        }
+      },
+      "solar": {
+        "title": "Solar Monitoring",
+        "description": "Select the phase count and CT power sensors from your inverter. Negative values indicate export. For single-phase setups, only Phase 1 CT is required.",
+        "data": {
+          "phase_count": "Number of phases",
+          "ct1_power": "Phase 1 CT power sensor",
+          "ct2_power": "Phase 2 CT power sensor (3-phase only)",
+          "ct3_power": "Phase 3 CT power sensor (3-phase only)"
+        }
+      },
+      "optional": {
+        "title": "Optional Devices",
+        "description": "Configure optional devices. Leave empty to skip.",
+        "data": {
+          "hp_aux_heater": "Heat pump auxiliary heater sensor (interlock)",
+          "circulation_pump": "DHW circulation pump switch (enables bath boost)",
+          "pump_schedule": "Pump schedule entity (restored after bath boost)"
+        }
+      }
+    },
+    "abort": {
+      "already_configured": "Already configured. Only one instance is supported."
+    }
+  },
+  "options": {
+    "step": {
+      "init": {
+        "title": "Reconfigure Entities",
+        "description": "Update entity references for the integration.",
+        "data": {
+          "boiler_temp_sensor": "Boiler temperature sensor",
+          "heater_relay": "Heater relay switch",
+          "phase_count": "Number of phases",
+          "ct1_power": "Phase 1 CT power sensor",
+          "ct2_power": "Phase 2 CT power sensor (3-phase only)",
+          "ct3_power": "Phase 3 CT power sensor (3-phase only)",
+          "hp_aux_heater": "Heat pump auxiliary heater sensor (interlock)",
+          "circulation_pump": "DHW circulation pump switch (enables bath boost)",
+          "pump_schedule": "Pump schedule entity (restored after bath boost)"
+        }
+      }
+    }
+  },
+  "entity": {
+    "climate": {
+      "boiler_aux_heater": {
+        "name": "Boiler Auxiliary Heater"
+      }
+    },
+    "sensor": {
+      "total_power": {
+        "name": "Heater Power"
+      },
+      "pv_power": {
+        "name": "Heater PV Power"
+      },
+      "grid_power": {
+        "name": "Heater Grid Power"
+      },
+      "total_energy": {
+        "name": "Heater Energy"
+      },
+      "pv_energy": {
+        "name": "Heater PV Energy"
+      },
+      "grid_energy": {
+        "name": "Heater Grid Energy"
+      },
+      "bath_boost_remaining": {
+        "name": "Bath Boost Remaining"
+      },
+      "decision_reason": {
+        "name": "Decision Reason"
+      },
+      "pv_state": {
+        "name": "PV Excess State"
+      }
+    },
+    "binary_sensor": {
+      "decision": {
+        "name": "Heater Decision"
+      },
+      "pv_sufficient": {
+        "name": "PV Power Sufficient"
+      },
+      "running_on_pv": {
+        "name": "Running on PV"
+      },
+      "running_on_grid": {
+        "name": "Running on Grid"
+      },
+      "bath_boost_active": {
+        "name": "Bath Boost Active"
+      }
+    },
+    "switch": {
+      "manual_override": {
+        "name": "Manual Override"
+      },
+      "allow_usage": {
+        "name": "Allow Aux Heater Usage"
+      },
+      "pv_excess_mode": {
+        "name": "PV Excess Mode"
+      },
+      "boost_all_modes": {
+        "name": "Boost in All Modes"
+      }
+    },
+    "number": {
+      "cut_off_temp": {
+        "name": "Cut-off Temperature"
+      },
+      "temp_hysteresis": {
+        "name": "Temperature Hysteresis"
+      },
+      "pv_target_temp": {
+        "name": "PV Target Temperature"
+      },
+      "pv_buffer": {
+        "name": "PV Excess Buffer"
+      },
+      "heater_power": {
+        "name": "Heater Power Rating"
+      },
+      "pv_start_delay": {
+        "name": "PV Excess Start Delay"
+      },
+      "pv_stop_delay": {
+        "name": "PV Excess Stop Delay"
+      },
+      "temp_normal": {
+        "name": "Normal Preset Temperature"
+      },
+      "temp_eco": {
+        "name": "Eco Preset Temperature"
+      },
+      "temp_boost": {
+        "name": "Boost Preset Temperature"
+      },
+      "temp_sleep": {
+        "name": "Sleep Preset Temperature"
+      },
+      "temp_away": {
+        "name": "Away Preset Temperature"
+      },
+      "bath_boost_duration": {
+        "name": "Bath Boost Duration"
+      },
+      "boost_all_modes_hysteresis": {
+        "name": "All Modes Boost Hysteresis"
+      },
+      "boost_recovery_offset": {
+        "name": "Boost Recovery Offset"
+      }
+    },
+    "button": {
+      "start_bath_boost": {
+        "name": "Start Bath Boost"
+      },
+      "cancel_bath_boost": {
+        "name": "Cancel Bath Boost"
+      }
+    }
+  },
+  "services": {
+    "start_bath_boost": {
+      "name": "Start Bath Boost",
+      "description": "Start the bath boost timer with pump activation."
+    },
+    "stop_bath_boost": {
+      "name": "Stop Bath Boost",
+      "description": "Stop an active bath boost, restore pump schedule and preset."
+    }
+  }
+}
@@ -0,0 +1,80 @@
+"""Switch entities for Boiler Auxiliary Heater Control."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from homeassistant.components.switch import SwitchEntity
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.const import EntityCategory
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers.entity import DeviceInfo
+from homeassistant.helpers.entity_platform import AddEntitiesCallback
+from homeassistant.helpers.restore_state import RestoreEntity
+
+from .const import DOMAIN, SWITCH_DEFINITIONS
+
+
+async def async_setup_entry(
+    hass: HomeAssistant,
+    entry: ConfigEntry,
+    async_add_entities: AddEntitiesCallback,
+) -> None:
+    """Set up switch entities."""
+    coordinator = hass.data[DOMAIN][entry.entry_id]
+
+    entities = []
+    for key, defn in SWITCH_DEFINITIONS.items():
+        entity = BoilerAuxHeaterSwitch(coordinator, entry, key, defn)
+        entities.append(entity)
+
+    async_add_entities(entities)
+
+
+class BoilerAuxHeaterSwitch(RestoreEntity, SwitchEntity):
+    """A mode toggle switch for the boiler aux heater."""
+
+    _attr_has_entity_name = True
+    _attr_entity_category = EntityCategory.CONFIG
+
+    def __init__(
+        self,
+        coordinator,
+        entry: ConfigEntry,
+        key: str,
+        defn: dict,
+    ) -> None:
+        """Initialize the switch entity."""
+        self.coordinator = coordinator
+        self._key = key
+        self._defn = defn
+        self._attr_unique_id = f"{entry.entry_id}_{key}"
+        self._attr_translation_key = key
+        self._attr_icon = defn["icon"]
+        self._attr_is_on = defn["default"]
+        self._attr_device_info = DeviceInfo(
+            identifiers={(DOMAIN, entry.entry_id)},
+            name="Boiler Auxiliary Heater",
+            manufacturer="Custom",
+        )
+
+    async def async_added_to_hass(self) -> None:
+        """Restore state on startup."""
+        await super().async_added_to_hass()
+        last_state = await self.async_get_last_state()
+        if last_state and last_state.state not in ("unknown", "unavailable"):
+            self._attr_is_on = last_state.state == "on"
+        # Register with coordinator
+        self.coordinator.register_switch(self._key, self)
+
+    async def async_turn_on(self, **kwargs: Any) -> None:
+        """Turn on the switch."""
+        self._attr_is_on = True
+        self.async_write_ha_state()
+        self.coordinator.async_request_refresh()
+
+    async def async_turn_off(self, **kwargs: Any) -> None:
+        """Turn off the switch."""
+        self._attr_is_on = False
+        self.async_write_ha_state()
+        self.coordinator.async_request_refresh()
@@ -0,0 +1,187 @@
+{
+  "config": {
+    "step": {
+      "user": {
+        "title": "Core Hardware",
+        "description": "Select the boiler temperature sensor and heater relay switch.",
+        "data": {
+          "boiler_temp_sensor": "Boiler temperature sensor",
+          "heater_relay": "Heater relay switch"
+        }
+      },
+      "solar": {
+        "title": "Solar Monitoring",
+        "description": "Select the phase count and CT power sensors from your inverter. Negative values indicate export. For single-phase setups, only Phase 1 CT is required.",
+        "data": {
+          "phase_count": "Number of phases",
+          "ct1_power": "Phase 1 CT power sensor",
+          "ct2_power": "Phase 2 CT power sensor (3-phase only)",
+          "ct3_power": "Phase 3 CT power sensor (3-phase only)"
+        }
+      },
+      "optional": {
+        "title": "Optional Devices",
+        "description": "Configure optional devices. Leave empty to skip.",
+        "data": {
+          "hp_aux_heater": "Heat pump auxiliary heater sensor (interlock)",
+          "circulation_pump": "DHW circulation pump switch (enables bath boost)",
+          "pump_schedule": "Pump schedule entity (restored after bath boost)"
+        }
+      }
+    },
+    "abort": {
+      "already_configured": "Already configured. Only one instance is supported."
+    }
+  },
+  "options": {
+    "step": {
+      "init": {
+        "title": "Reconfigure Entities",
+        "description": "Update entity references for the integration.",
+        "data": {
+          "boiler_temp_sensor": "Boiler temperature sensor",
+          "heater_relay": "Heater relay switch",
+          "phase_count": "Number of phases",
+          "ct1_power": "Phase 1 CT power sensor",
+          "ct2_power": "Phase 2 CT power sensor (3-phase only)",
+          "ct3_power": "Phase 3 CT power sensor (3-phase only)",
+          "hp_aux_heater": "Heat pump auxiliary heater sensor (interlock)",
+          "circulation_pump": "DHW circulation pump switch (enables bath boost)",
+          "pump_schedule": "Pump schedule entity (restored after bath boost)"
+        }
+      }
+    }
+  },
+  "entity": {
+    "climate": {
+      "boiler_aux_heater": {
+        "name": "Boiler Auxiliary Heater"
+      }
+    },
+    "sensor": {
+      "total_power": {
+        "name": "Heater Power"
+      },
+      "pv_power": {
+        "name": "Heater PV Power"
+      },
+      "grid_power": {
+        "name": "Heater Grid Power"
+      },
+      "total_energy": {
+        "name": "Heater Energy"
+      },
+      "pv_energy": {
+        "name": "Heater PV Energy"
+      },
+      "grid_energy": {
+        "name": "Heater Grid Energy"
+      },
+      "bath_boost_remaining": {
+        "name": "Bath Boost Remaining"
+      },
+      "decision_reason": {
+        "name": "Decision Reason"
+      },
+      "pv_state": {
+        "name": "PV Excess State"
+      }
+    },
+    "binary_sensor": {
+      "decision": {
+        "name": "Heater Decision"
+      },
+      "pv_sufficient": {
+        "name": "PV Power Sufficient"
+      },
+      "running_on_pv": {
+        "name": "Running on PV"
+      },
+      "running_on_grid": {
+        "name": "Running on Grid"
+      },
+      "bath_boost_active": {
+        "name": "Bath Boost Active"
+      }
+    },
+    "switch": {
+      "manual_override": {
+        "name": "Manual Override"
+      },
+      "allow_usage": {
+        "name": "Allow Aux Heater Usage"
+      },
+      "pv_excess_mode": {
+        "name": "PV Excess Mode"
+      },
+      "boost_all_modes": {
+        "name": "Boost in All Modes"
+      }
+    },
+    "number": {
+      "cut_off_temp": {
+        "name": "Cut-off Temperature"
+      },
+      "temp_hysteresis": {
+        "name": "Temperature Hysteresis"
+      },
+      "pv_target_temp": {
+        "name": "PV Target Temperature"
+      },
+      "pv_buffer": {
+        "name": "PV Excess Buffer"
+      },
+      "heater_power": {
+        "name": "Heater Power Rating"
+      },
+      "pv_start_delay": {
+        "name": "PV Excess Start Delay"
+      },
+      "pv_stop_delay": {
+        "name": "PV Excess Stop Delay"
+      },
+      "temp_normal": {
+        "name": "Normal Preset Temperature"
+      },
+      "temp_eco": {
+        "name": "Eco Preset Temperature"
+      },
+      "temp_boost": {
+        "name": "Boost Preset Temperature"
+      },
+      "temp_sleep": {
+        "name": "Sleep Preset Temperature"
+      },
+      "temp_away": {
+        "name": "Away Preset Temperature"
+      },
+      "bath_boost_duration": {
+        "name": "Bath Boost Duration"
+      },
+      "boost_all_modes_hysteresis": {
+        "name": "All Modes Boost Hysteresis"
+      },
+      "boost_recovery_offset": {
+        "name": "Boost Recovery Offset"
+      }
+    },
+    "button": {
+      "start_bath_boost": {
+        "name": "Start Bath Boost"
+      },
+      "cancel_bath_boost": {
+        "name": "Cancel Bath Boost"
+      }
+    }
+  },
+  "services": {
+    "start_bath_boost": {
+      "name": "Start Bath Boost",
+      "description": "Start the bath boost timer with pump activation."
+    },
+    "stop_bath_boost": {
+      "name": "Stop Bath Boost",
+      "description": "Stop an active bath boost, restore pump schedule and preset."
+    }
+  }
+}
@@ -0,0 +1,5 @@
+{
+  "name": "Boiler Auxiliary Heater Control",
+  "content_in_root": false,
+  "homeassistant": "2024.1.0"
+}