Feature request: implement switch to enable intake fan only, exhaust fan only, none or both

[adorobis]

This feature is not described in the protocol documentation but someone has reverse engineered it in the RS485 versions and documented it here: https://matsab.de/images/comfoair/Protokoll_CA500_Avignon.pdf

So we need to identify respective command to be sent and the return message.

[PimDoos]

This could be implemented via the MQTT Select integration, introduced in 2021.7

[adorobis]

Thanks, but the HA and MQTT part is not an issue. The missing part is the RS232 commands to switch those options. They are missing in the available protocol documentation.

[ItsEcholot]

How I solved this in esphome-comfoair is by (ab-)using the 0x00 0xCF command:

And setting the values to 0 for the supply and/or the exhaust side to turn them off and setting them back to the original values when turning them back on.

[adorobis]

@ItsEcholot Great, thanks! Could you post (or in your repo) a list of all the entities that your esphome-comfoair exposes to HA?

[ItsEcholot]

It exposes the following sensors as entities:

  sensor::Sensor *fan_supply_air_percentage{nullptr};
  sensor::Sensor *fan_exhaust_air_percentage{nullptr};
  sensor::Sensor *fan_speed_supply{nullptr};
  sensor::Sensor *fan_speed_exhaust{nullptr};
  binary_sensor::BinarySensor *is_bypass_valve_open{nullptr};
  binary_sensor::BinarySensor *is_preheating{nullptr};
  sensor::Sensor *outside_air_temperature{nullptr};
  sensor::Sensor *supply_air_temperature{nullptr};
  sensor::Sensor *return_air_temperature{nullptr};
  sensor::Sensor *exhaust_air_temperature{nullptr};
  sensor::Sensor *enthalpy_temperature{nullptr};
  sensor::Sensor *enthalpy_humidity{nullptr};
  sensor::Sensor *ewt_temperature{nullptr};
  sensor::Sensor *reheating_temperature{nullptr};
  sensor::Sensor *kitchen_hood_temperature{nullptr};
  sensor::Sensor *return_air_level{nullptr};
  sensor::Sensor *supply_air_level{nullptr};
  binary_sensor::BinarySensor *is_supply_fan_active{nullptr};
  binary_sensor::BinarySensor *is_filter_full{nullptr};
  sensor::Sensor *bypass_factor{nullptr};
  sensor::Sensor *bypass_step{nullptr};
  sensor::Sensor *bypass_correction{nullptr};
  binary_sensor::BinarySensor *is_summer_mode{nullptr};

The following service, which allows turning the fans on or off: register_service(&ComfoAirComponent::control_set_operation_mode, "climate_set_operation_mode", {"exhaust_fan", "supply_fan"});

And finally it implements most features of a HA "climate" entity, like setting fan level (low, med, high) and setting the target temperature.

[adorobis]

OK, thanks! Looks quite complete. Maybe one day I'll get rid of the cable from the unit to my NAS.

[euDominic]

Is there already a positive development on this? would be very happy about this function.

[adorobis]

No progress really :) I was not seeing it as a priority so far but I have a clarity how this can be achieved so I'll try to pick it up in the next days.

[euDominic]

No progress really :) I was not seeing it as a priority so far but I have a clarity how this can be achieved so I'll try to pick it up in the next days.

That would be great, I definitely have a good use for it.

[adorobis]

So here it is. Implemented and working ok in my system. https://github.com/adorobis/hacomfoairmqtt/pull/53 New select entity will show up in HA enabling control of both fans. In order for it to work properly a new section in config.ini is required - it defines the fan speed % for each ventilation level. There are no defaults so the program will most likely fail without it.

[PimDoos]

Works like a charm!