nest thermostat wont fire up boiler for central heating but hot water is ok

[bobbymcg7]

HI my Nest thermostat is no longer turning on the boiler for the central heating but it does fire up for the hot water when boosting is selected

[bobbymcg7]

I’ve now also turned the heating onto manual using the heatlink and that is still not firing up the boiler 

[Bester]

I would check what your Nest thinks it is via Equipment settings.

I reset mine recently and it went from a Combi boiler to thinking it was an AC Extractor. No idea how it came to that conclusion but a simple fix in settings.

[bobbymcg7]

thanks checked that and its still a combi boiler thankfully 🙂

[Bester]

I think that is the issue, System Boilers use Boost. Combi Boilers don't boost, it is on demand.

Sounds like yours should be set to System, not Combi.

[bobbymcg7]

no its a combi boiler - the boost function just turns the the hot water on instantly rather than using a timer - weve had our nest thermostat for years and its all worked fine, hotwater and CH. From last week the CH just wont turn on, even used the manual button on the Heatlink -  

[Bester]

Hmm, then it probably isn't the Thermostat.

The boiler might be protecting itself and the central heating part of the system.

Checked pressure level, at least 1 bar?

Condensate pipe not blocked or frozen?

Radiator air bled?

If all those are checked its time to get Gas engineer out I'm afraid.

[bobbymcg7]

Yep all checked - trying to sort the heating engineer now 

[LarisaL]

Hi @bobbymcg7, thanks for reaching out! I'm so sorry to hear about this situation. Could you please tell me how many lights you see on the heat link? Also in situations like this we perform a click test to determine if the issue is related to your thermostat or to another part of your heating system like a valve, wires or with the boiler itself. That being said, please go near your Heat Link and turn the heating on from the app and let me know if you hear a click. You should hear a click when you turn on the heating and another click when you turn it off. Just to make sure that the relay is working properly, please try that 5 or 6 times and let me know if you hear a click at every command.
 

Thank you for your help, @Bester!

[Vladut]

Hi there, just checking in with you. Did you manage to check our last message?

[TudorL]

Since I haven't heard from you in a while, I'll need to close this thread, but you can always open a new one if you have any issues. Have a good one and stay safe in the meantime!