Fallback temperature sensor when unavailable

[nicola-spreafico]

Hello,
my temperature sensors for all the rooms are Zigbee AQARA temperature/humidity sensor, battery powered.

Here is how I configured my sensor:

It happens sometimes that those sensor may become offlline/unavailable and it is my understanding that without a valid value, the VTherm goes into off mode, which I guess is by design to avoid keep the heating on without a reference.

I'm wondering if there is a way to provide to VTherm some sort of fallback sensor for the temperature, like for example I already have a template temperature sensor that calculate the average temperature of the house, doing an average of all the available sensors:

template:
  - sensor:
      - name: temperature_mean
        unique_id: temperature_mean
        state: >
          {% set sensors = [
            'sensor.temp1',
            'sensor.temp2',
            'sensor......',
          ] %}

          {% set num_values = sensors
            | map('states')
            | reject('in', ['unknown', 'unavailable'])
            | list
            | count
          %}

          {% set sum_values = sensors
            | map('states')
            | reject('in', ['unknown', 'unavailable'])
            | list
            | map('float')
            | list
            | sum
          %}

          {{ (sum_values / num_values) | round(2) }}
        unit_of_measurement: °C

In the VTherm configuration I can see I can provide only a temperature sensor. Is there already a built-in function that I'm not aware of where I can configure a fallback sensor for when the main one is not available?

My raw idea is that I can create a virtual sensor counterpart for each real one, such as

virtual_sensor_temperature = real sensor if available, fallback value when missing

This would be a suitable way, but maybe there is already some built-in functionality.

Thank you

[jmcollin78]

Hello,

The only builtin function is the safety mode when the temperature sensor is not available. See: https://github.com/jmcollin78/versatile_thermostat/blob/main/documentation/en/troubleshooting.md#why-is-my-versatile-thermostat-going-into-safety-mode

The temperature regulation is based on the difference between the room temperature and the target temperature. So using a temperature sensor which is not impacted by the heating system is a very bad idea.
If the heater heats but the temperature don't increase, it will heats infinitly and you risk an overheat issue.

I cannot advice to use the method you propose. Just make your temperature sensor works.

[nicola-spreafico]

Hello,
thank you as always for your help.

I entirely agree with you that is very bad idea, but this would be like for emergencies only, such as on last december a sensor went offline in the middle of the night and I woke up with a cold room, while the sensor was fixed as soon as possible I had that problem at the morning.

In any case I understand your suggestion and why this would be a bad idea. I will try to think of a better idea for this
Thank you