Radiator thermostat

Radiator thermostat

Shelly TRV control with external temperature sensor

If you have a large room, it might be necessary to install additional temperature sensors to get the most accurate room temperature measurements. In some cases, you might want to control the Shelly TRV from a temperature sensor in another room. Luckily, this setup is simple if you follow the below steps. Note that it might be easier to do the setup from a computer. Go to https://control.shelly.cloud/

Step 1: Enable temperature correction

For the TRV to receive temperature information from an external sensor, you need to enable external temperature corrections in the device settings.

Step 2: Enable/disable under floor heating mode

It can seem strange that you need to enable or disable under floor heating mode. But there is a good reason for this:

  1. If you enable under floor heating mode, the built-in temperature sensor in the TRV will be disabled. You will then only get temperature information from the external sensor.
  2. If you disable under floor heating mode, the TRV will calculate an offset between the build-in temperature sensor and the external temperature sensor. This is beneficial if you have a large room and would need more measurements.

Step 3: Set up an action to report temperature measurements

Go to the “action” section of your new temperature sensor. You can use a Shelly Plus H&T and/or a Shelly Plus Addon combined with a DS18B20 temperature sensor to report temperature.

Before you can add an action to the Plus H&T you might need to wake-up the device by opening the back cover and pressing the wake-up button three times quickly.

  1. Click on “add action”
  2. Give the action a name like “temperature reporting”
  3. Set an active period for the sensor to report the temperature measurements.
  4. Set the condition to “temperature change” and condition to “any”.
  5. Insert the URL (remember to change the IP address so it matches the IP of the TRV): http://192.168.X.X/ext_t?temp=${ev.tC}

Step 5: Done

You are now done. You might need to wait until the next temperature update from the sensor before you will see the new temperature measurement on the TRV.