UK Nest not running boiler for heating

[murrayfisher]

My nest thermostat seems to have stopped firing my boiler for heating, either in schedule or manual mode.

Having tried a reset on the nest, checking the heat link, running that manually, and turning up the thermostat to a high temperature, nothing seems to make the boiler fire for heating. It does fire for hot water, both in schedule and manual modes.

When increasing the nest heating temperature, it displays as heating, but doesn't fire the boiler at all.

The unit is bang on 2 yrs old.

[Simonh12]

Following as I've just experienced the same this evening. 

[murrayfisher]

UPDATE: After some fairly lengthy investigation with a Google support team member, the suggestion was that there may be a faulty relay in the boiler. This requires further assessment by a plumber or professional tradesman. Therefore, it may not be the Nest that's at fault on this occasion.

[murrayfisher · Accepted solution]

SOLVED: This issue was caused by a zone valve that had broken. There's one for hot water, and another for heating. As such, it was not a Nest issue, but Google Nest support helped me eliminate that part of the puzzle before finding the real culprit.

[CristianC]

Hey @murrayfisher. I'm happy to hear that you managed to get it resolved. Let me know if there's anything I can do for you. 

Hey @Simonh12. How's it going with your thermostat? Did you check your valve?

[CristianC]

Hello again. Just checking in. Do you still need my help?

[murrayfisher]

No thank you. My issue was solved, after investigation of my boiler, which was at fault. Google Nest phone support helped eliminate the Nest itself from the puzzle.

[CristianC]

Awesome. I'm happy to hear that. If anything comes up, I'm only a message away.