Cannot turn off underfloor heating system

[Dantheman]

Dear members,

We have a underfloor heating system (warm water) in the kitchen with it's own control unit. For some reason we cannot turn it off and we believe it started after a visit by one of the British Gas Engineers fixing the problem where we had no hot water but with the central heating system still working.

We have now noticed when the weather is getting warmer that the thermostat does not work making the kitchen too warm. I have even turned off the system at the control unit but the floor is still warm.

Can anyone cast any light on this? We would be be grateful for any advice on what the problem could be.

Best regards

Dantheman

[tabath]

Depends what boiler you have but could be faulty diverter valve letting DHW intoCH side.

[Dantheman]

Hello Tabath,

Thank you for your input. The boiler we have is a Glow Worm (30sxi) Condensing System Boiler.

The valve you mention, where would I find it? close to the boiler or the under floor heating pump?

Best regards

Dan

[tabath]

Didn't realise you had so system boiler so ignore last suggestion. Probably motorised valve that shuts off CH loop when there is no demand.You can manual push the lever across which should do the trick to check it.

[Dantheman]

Tabath,

Once again thank you for trying to help. I have taken some time today to explore this again and have found that the Room Thermostat was wrongly wired. It took a while to find out but in essence the pump for the heating system was not acknowledging input from the room thermostat and was entirely controlled by the temperature sensor in the Zonal Regulation Unit (ZRU). When the water reached 45 degrees the sensor activated the pump with the Room Thermostat not wired to override that command.

I have tested the revised wiring and it works absolutely fine. The installation was wrong from the beginning but somehow we had not noticed the malfunction earlier.

Best regards

Dantheman