TRVs constantly cycling zone valve

I have got a wireless receiver and two wired thermostats all based in the garage working which replaces three nest heat link 3rd generation, one for each heating zone.

1) Wireless receiver- controls ground floor zone valve and hot water. Has wireless temperature sensor in office on ground floor. Doesn’t seem to have any issues So far
2) wired thermostat- controls 1st floor heating zone valve. Smart TRVs on 1st floor radiators use this as zone controller. Seems to cycle zone valve constantly unless the thermostat itself states heating required.
3) wired thermostat- controls 2nd floor heating zone valve. Smart TRVs on 2nd floor radiators use this as zone controller. Seems to cycle zone valve constantly unless the thermostat itself states heating required.

Can anyone advise if this is normal? I was expecting the TRVs to be able to call for heat from individual rooms Via the zone controller and keep the boiler on while the room heats. This cycling of the valve causes the boiler to reject new heat requests for a period of time which ends up with it not gaining heat correctly

Answers

  • I had a wired thermostat and later added smart radiator stats to the same zone and had the same problem. The solution was to link out the wired stat connections and let it connect wirelessly to the extension kit which replaced the old programmer. The smart radiator stats can now call the extension kit independently and it works properly now.

  • Thanks Romac. Was your system multi zone? I ask as I can’t link out the stats as they control independent zone valves which is why I went for three “zone controllers”. If yours is multi zone I’d really appreciate knowing how you linked out the wiring
  • Yes, it is multizone, I have a Tado room stat (the one that was wired) controlling zone 1 through the Extension kit (downstairs) which operates one motorised valve and a separate Tado room stat upstairs which controls a second motorised valve. The extension kit also controls hot water on a third motorised valve. I now also have 8 Tado TRVs in separate rooms that can activate zone one now that everything in that zone is wireless. If you don’t have an extension kit then I think the wireless receiver might be an option. I have the option in the Tado settings to decide if the TRVs switch zone 1 or 2, you need to choose the correct option. I might add some more TRVs to zone 2 later now that the price of gas is through the roof so that I can set different temperatures and times for each room.

  • Have a look at these manuals https://www.tado.com/all-en/professional-manuals

    I was stuck until I read them

  • Thanks for the extra info. Your setup sounds exactly the same as what I need (and have configured) so I think I have an issue I’ll ask support to assist with

    To be clear I have a wireless room stat communicating with the wireless extender. The extender controls the motorised valve for zone 1. All rooms in this zone have TRVs and are set to use the wireless extender as the controller. The wireless controller also controls a separate motorised valve for the hot water

    I then have a wired stat controlling the motorised valve for zone 2. All rooms in this zone have TRVs which are set to use the wired stat as zone controller

    I have a further wired stat controlling the motorised valve for zone 3. All rooms in this zone have TRVs which are set to use the wired stat as zone controller

    What I’m seeing is when the wired thermostats are not calling for heat but one of the TRVs calls for heat the valve opens for around 30 seconds and closes again. This then seems to cycle between open and closed at frequent intervals far too short for the boiler to heat correctly
  • Sorry when I say extender I mean the wireless receiver but think they’re one in the same device really
  • Yes, that sounds exactly the same, I think the wireless extension and the receiver basically do the same thing so it should work ok. I actually have multiple TRVs in one open plan room that are linked and when they initially call for heat stay on until the set temp is achieved then cycle. Have you updated the firmware on everything? Are the TRVs close enough to the bridge? I had to move my bridge to a more central location using a mains network extender, I know a few people have had to do this as the range wasn’t sufficient.

  • I think I may have cracked it thanks to your link to the professional docs. I essentially just re-saved the config settings for each thermostat making sure stat 1 was set to wireless and controlling heat zone 1, stat 2 wired and heat zone 2 and stat 3 wired and heat zone 3. I think this may have “reset” something in either the controllers or the valves (they all seemed to cycle). As a short test I was able to call for heat from a single room and that zone came on and, most importantly, stayed on for over 1 minute. I’ll perform longer tests tomorrow but I think maybe I had a corrupt config somewhere at a software level. Thanks so much for assisting here Romac. Much appreciated