Frisquet Boiler for ESPHome

This custom component allows communication between an ESPHome device (ESP8266 or ESP32) and a Frisquet heating boiler (equipped with Eco Radio System remote thermostat).

This ESPHome Custom Component is strongly integrated with Home Assistant where it appears as a standard climate device. However, if necessary, it can be used with any other home automation system through MQTT. In that case MQTT functionnality should be enabled in the the yaml configuration file.

References

This work is strongly inspired from:

and from the discussions made in this thread:

https://easydomoticz.com/forum/viewtopic.php?f=17&t=1486sid=d2f41ac68e5bab18fd412a192a21c2c4 (French)

Wiring

The ESPHome replaces the original Eco Radio System HF receiver and is conneted to the boiler main board through a micro-fit 4 socket.

ESP32	Boiler Side	Pin number
GND	black wire	1
Pin 21 (configurable)	yellow wire	2
5V	red wire (optional)	3

Micro-fit 4 pin out:

Defined viewing direction for the connector pin out:

Receptable - rear view
Header - front view

Note: It has been observed that the current supplied by the boiler main board is not sufficent to power the ESP32.

Installation

The Frisquet ESPHome component concists in two custom components:

HeatCurveClimate.h a custom Climate component that will control the boiler water setpoint based on external temperature measurement and ambiant temperature setpoint.
FrisquetBoilerFloatOutput.h a custom Output component that will actually communicate with the Frisquet boiler.

Both files HeatCurveClimate.h and FrisquetBoilerFloatOutput.h must be copied in your esphome configuration folder.

Your yaml configuration file must show at minimum the following code:

esphome:
  name: myFrisquetBoiler

  # Installation of the two custom components
  includes:
  - FrisquetBoilerFloatOutput.h
  - HeatCurveClimate.h

# Initialisation of the custom output component
output:
  - platform: custom
    type: float
    lambda: |-
      auto boiler_float_output = new FrisquetBoilerFloatOutput();
      boiler_float_output->set_max_power(1.0);
      boiler_float_output->set_min_power(0);
      boiler_float_output->set_zero_means_zero(true);
      App.register_component(boiler_float_output);
      return {boiler_float_output};
    outputs:
      id: boiler_cmd

# Template sensor to send back the boiler water setpoint to homeassistant
sensor:
  - platform: template
    id: heating_curve
    name: "Consigne chaudière"
    unit_of_measurement: "°C"
    accuracy_decimals: 1

# Initialisation of the custom climate component
# - current_temperature : id of the ambiant temperature sensor
# - outdoor_temperature : id of the external temperature sensor

climate:
  - platform: custom
    id: custom_climate
    lambda: |-
      auto custom_climate = new HeatCurveClimate();
      custom_climate->set_sensor(id(current_temperature));
      custom_climate->set_outdoor_sensor(id(outdoor_temperature));
      custom_climate->set_output(id(boiler_cmd));
      custom_climate->set_water_temp_sensor(id(heating_curve));
      custom_climate->set_heat_factor(1.4);
      custom_climate->set_offset(21);
      custom_climate->set_output_conversion_factor(1.90);
      custom_climate->set_output_conversion_offset(-41);
      App.register_component(custom_climate);
      return {custom_climate};

Temperature sensors

At minimum, two temperature sensors must be defined : ambiant temperature and external (outdoor) temperature.

This can be done using the Home Assistant API :

sensor:
  - platform: homeassistant
    id: current_temperature
    entity_id: sensor.aqara_salon_temperature
    unit_of_measurement: "°C"
    filters:
      - filter_out: nan
      - heartbeat: 60s
        
  - platform: homeassistant
    id: outdoor_temperature
    entity_id: sensor.outdoor_temperature
    unit_of_measurement: "°C"
    filters:
      - filter_out: nan
      - heartbeat: 60s

Alternatively, the mqtt_subscribe platform can be used if Home Assistant is not used:

sensor:
  - platform: mqtt_subscribe
    id: current_temperature
    topic: the/current_temperature/topic
    unit_of_measurement: "°C"
    filters:
      - filter_out: nan
      - heartbeat: 60s
        
  - platform: mqtt_subscribe
    id: outdoor_temperature
    topic: the/outdoor_temperature/topic
    unit_of_measurement: "°C"
    filters:
      - filter_out: nan
      - heartbeat: 60s

Tuning

Heat curve definition

The boiler water temperature is calculated from the outdoor temperature:

WaterReturnTemperature = (TargetTemp - OutdoorTemp) * HeatFactor + Offset

HeatFactor and Offset are defined using the following lines in the yaml configuration file:
```
custom_climate->set_heat_factor(1.4);
custom_climate->set_offset(21);
```
Those two parameters strongly depend on the heat insulation of the house. Therefore slight adjustments may be necessary to find the best settings. Guidelines to do so can be found here (French).
Boiler setpoint conversion factor and offset

The boiler setpoint (integer in the [0 - 100] range) and the water return temperature are linked by the following formula:

Setpoint = WaterReturnTemperature * ConversionFactor + Offset

ConversionFactor and Offset are defined using the following lines in the yaml configuration file:
```
custom_climate->set_output_conversion_factor(1.90);
custom_climate->set_output_conversion_offset(-41);
```

raedkit / frisquet-esphome