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My heating system doesn't respond to commands from the Thermostat, what should I do?


If the Thermostat has just been installed and the functionning test is inconclusive, check that your system is compatible and that all the wires are securely connected.
For help connecting the wires of the Thermostat to the heating system, please read this article.

The Thermostat worked previously...

If the heating system has already been properly controlled by the Thermostat but it no longer does, it may have been installed on an incompatible device. Check that all the technical switching specifications of the Thermostat are followed:

  • Dry contact Thermostat and Relay, potential free (ON / OFF)
  • Switching current: max 4A
  • Switching voltage: max 250V AC
  • Switching power: max 120VA (4A under 30V, 1A under 110V / 120V or 0.5A under 220V / 240V)
  • Power factor: cos φ > 0.8

Failure to comply with these characteristics may cause the Thermostat to malfunction prematurely after a while.

If the device controlled by the Thermostat are within specifications, check the following points:

  1. Disconnect the Relay from power, wait a minute, then reconnect it. The LED should flash 5 times when the power is turned back on. In the case of a wireless installation, make sure that the Relay is correctly pushed onto its boiler adapter (press hard on it).
  2. Replace the Thermostat batteries with new ones (alkaline, 1.5V, good quality and not expired). The screen should flash when the power is turned back on, then display the temperature digits after a few minutes.
  3. Switch off the boiler, wait a minute, then switch it on again. Check that the boiler is not faulty (error code...) and that the water circuit pressure is correct (usually between 1 and 2 bars). Also check that it is not in summer mode (domestic hot water production only), and that the temperature of the heating water is high enough.

Once these checks have been carried out, apply the OFF setpoint to the Thermostat. Wait 30 seconds, then apply the MAX setpoint. A "click" should be heard from the Thermostat (if used in wired mode) or from the Relay (wireless mode).

If the "click" is audible but the heater still does not respond to the test, then the connection of the control wires should be checked.

Turn off the power, then follow these steps depending on the type of installation chosen:

  1. Wired: detach the Thermostat from its wall plate, then unscrew the terminal block cover screw. Remove the terminal block cover, check the integrity of the 2 wires then check the tightness of the 2 terminal block screws. Finally, check the integrity of the Thermostat's control pins.
  2. Wireless: remove the Relay from its boiler adapter (by pulling it hard). Check the integrity of the connections, on the boiler adapter side and on the Relay side. Then, open the boiler and check the connection of the power and control wires. They must be firmly tightened, and the boiler must not show signs of damage.

Finally, restore power and repeat the switching test.

If all these checks have been made, but the Thermostat still does not control your heating system, please send us a message specifying the exact make and model of the device being checked, including photos of the electrical connections.


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