Nest Issues

[dsb2020]

Hi everyone,

Hoping someone can shed some light on a heating issue I've been having. Four years ago, I had a new system installed, including boiler, unvented cylinder, pump, valves, and separate upstairs/downstairs zones controlled by Nest thermostats.

Everything worked fine until recently. Now, when I try to turn on the downstairs heating (either through the Nest thermostat or the app), it doesn't respond, and I hear a clicking noise coming from the upstairs cupboard where the Nest Heat Link and Honeywell Motorised zone valves are located.

At first, I thought the downstairs zone valve might be faulty, but here's the odd part - power cycling the boiler (which is downstairs) temporarily fixes the problem.

This makes me wonder if it's not a simple valve issue. Could it be:

• A wiring problem between the Heat Link and the valve?
• An issue with the Nest Heat Link itself?
• A problem with the boiler's control board affecting the zone valve signal?

Any suggestions on how to troubleshoot this further would be greatly appreciated!

I've tried restarting the Nest thermostats and the Nest Heat links

Thanks in advance,

 

[Stuckinarut]

By “power cycling” I guess you mean chimney sweep/high fire? It’ll likely be the motorised valve, the microswitch won’t be making contact to send a switch live to the boiler.

 

[dsb2020]

By “power cycling” I guess you mean chimney sweep/high fire? It’ll likely be the motorised valve, the microswitch won’t be making contact to send a switch live to the boiler.

Thanks!

By "power cycling" I mean turning the boiler off and back on... any idea why this would make it work again??

 

[Stuckinarut]

If you’re turning it off and on at the fuse don’t connection unit (white switch on the wall) this kills all power, which could bring the motor back to original position.