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What is the relationship between radiator, thermostat and extension kit?

I used to have just smart valves everywhere, the thermostat in the hall, and an old analog style timer in permanently ON position for heating. Worked a charm.

I added the extension kit and can now control HW too - great - except something has changed. The radiator valves no longer turn the boiler on. The thermostat does, but that means I have to heat the hall if I want to heat any other room. This is not cost effective, and not what I wanted.

e.g. My hallway is 19.1, set to 18. My living room is 17, set to 20 - so should be heating but is not. If I override the hall schedule to, say, 20, it kicks in and heats the hallway and the living room.

Is this how this is SUPPOSED to work with an extension kit? If so can I reconfigure it somehow so radiator valves trigger heating, or do I have to rewire something somewhere?

As an aside I am still using the 230V switched (wired) settings as I replaced the thermostat first, and added the extension kit later.

Thanks in advance.


  • GrilledCheeseGrilledCheese ✭✭✭
    edited September 1

    Your configuration is incorrect. For heating control there’s a relay in the wall thermostat and another in the extension kit. Currently both of these relays must close for the boiler to fire up, hence the need to turn on the hall thermostat.

    Remember your programmer was permanently set to on, which had the effect of permanently switching that relay on. You’ll have to speak to the support team to get the configuration changed over.

  • Had to do the same with mine when I installed. This is something the end user should be able to manage without having to contact support

    They will change it so any device (thermostat or TRV) can call for heat. You will notice that once done, the room thermostat relay no longer clicks as it's always closed. The heating is turned on/off using the relay in the extension kit

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