boiler and nest no longer playing nice

[dagnut]

Hello, have been using a Nest thermostat for a few years, but something has stopped working.

The equipment is

Nest Thermostat: Display 2.8
Heat Link Amber 1.5

The boiler is a Worcester Greenstar 30 CDI

Heat Link is connected fine and green

When the thermostat comes on the boiler doesn’t fire up, you can hear the Heat Link click but the boiler does nothing.

When putting the Heat Link to a manual setting, the manual controls on the boiler do not fire up the pilot light or the boiler - nothing happens

When pressing the central heating boost button on the boiler for 10 seconds, the boiler fires up fine.

The pressure gauge is at the right level.

Cant work out if a valve has gone in the boiler or if the issue is with the Heat Link being quite old now, or something else altogether.

Any help appreciated!

[TudorL]

Hi there and thanks for reaching our community. I'm sorry you're having this issue, but we're going to get to the bottom of it in no time. Could you please tell me when did the issue start? Additionally, could you please confirm if you have a system boiler? 

[dagnut]

hey there, the issue started about 2 weeks ago, and the boiler is a Combi boiler, about 3 years old.

thanks!

[LarisaL]

Thank you for the answers. This might be happening because of various reasons and 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. 

[dagnut]

hey there, yup the thermostat triggers a click at the heat link both on, and off, every time, but it doesn't fire up the pilot light, as mentioned in the OG post.

If I switch the heat link to manual, the controls on the boiler dont fire up the pilot either, but the boiler does not seem to be at fault because if I click on the heat boost button on the boiler (which overrides heat link) the heating comes on fine.

Strangely, over the last 24 hours the boiler has fired up at random times even though heat link has been switched on and the thermostat was showing that the boiler was not heating. 

[Paul_R]

Hi there @dagnut! From the sound of it the thermostat sends the signal to the Heat Link, and the Heat Link also reacts to the commands, switching the relays (thus the click sounds). It is normal for the thermostat to not show that the boiler is running if the command didn't come from the thermostat, by this I mean that the thermostat wouldn't show that the heating is on if it was activated by the boiler. My guess would be that you are dealing with a stuck valve, as everything suggests that the Nest system functions correctly. 

[UanaC]

Hello there! Just checking, did you see my colleagues previous message?