Heating coming on when hot water is on.

[Antsheff]

Hi, Nest system working ok for three years. In the last month or so, there’s been occasions when I’ve had to boost the hot water via the app to kick start the heating. Now it’s a case of when the hot water is on, the heating is on whether I want it or not. Easter weekend and it’s 20 degrees outside. I’ve boosted the water just now with heating “off”. The radiators are now warming up. 

vaillant system boiler with a tank and valves up in the loft. 
Thanks!

[DragosC]

Hi there, @Antsheff.

Thanks for letting me know. Could you tell me please when did the situation start occurring at first and when was the thermostat installed? Also, what specific troubleshooting steps have you tried? Is your boiler an S plan with separate valves for heating and hot water, or is it a Y plan with a three port valve for both heating and hot water? 

[CristianC]

Hi there. Just checking in. How's it going with your thermostat? 

[Antsheff]

Hi. It seems that the heating zone valve has had it. The manual lever on top moves with no resistance. It used to wind the motor backwards and forwards but not now. 

[CristianC]

Hey @Antsheff. I'm happy to see that you found the culprit and I'm hoping you managed to resolve the issue. Let me know if there's anything I can do for you. 

[AnaM]

Hey there,

Just checking, do you need any further assistance?

[DragosC]

Since I haven't heard from you in a while, I'll have to close this thread. Should anything else come up, please open another thread and we'll take it from there. Have a good one and stay safe!