topic Re: Heatlink stopped working in Nest Thermostats

Heatlink stopped working

cunninghamb017 — Fri, 28 Nov 2025 19:43:46 GMT

I have a 3rd gen thermostat.

My heatlink has stopped working.

My thermostat is fine and the zone2 thermostat/heatlink does trigger the boiler to start so it's not a boiler issue.

The green light is on; manual stitch worked this morning but has stopped working, every since I restarted the heatink I think. I've had no work done, no changes recently to explain why it stopped working.

I have seen that in 2022/2023 there was a recall of heatlinks and Google were providing replacements. Is this still the case?

I am in Ireland.

Re: Heatlink stopped working

Frustratedddd — Sat, 29 Nov 2025 15:40:43 GMT

Just to confirm. You have 2 setups, one working correctly, the other has a Heat Link issue, correct?

Do you have lights on the Heat Link that has an issue?

Do you have motorised valves, and if so have you checked them?

Re: Heatlink stopped working

cunninghamb017 — Sat, 29 Nov 2025 21:48:29 GMT

Correct, 2 zones, 2 thermostats with 2 heatlinks.

Zone 2 is working correctly. The heatlink for zone 1 is faulty.

I don't have motorised valves.

Here are the answers to the standard set of troubleshooting questions I have seen elsewhere:

What color is the light on your Heat Link?

Green

Have you tried taking the Heat Link out of Manual Mode? If not, here's an article with instructions: Manually control heating when Heat Link is disconnected.

Yes, manual mode has stopped working too.

When was your thermostat installed?

Over 5 years ago.

Did the thermostat communicate with the Heat Link right after installation?

Yes

If yes, how long after did the problem start?

Over 5 years

Has any work been done on your heating system recently?

What type of thermostat do you have?

3rd generation: Display-3.4

How far apart are the Heat Link and the Nest thermostat?

Less than 1m.

Are they on the same floor?

Yes

Re: Heatlink stopped working

moralesvicente — Tue, 02 Dec 2025 18:18:14 GMT

Hello @cunninghamb017,

Thank you so much for posting in this community. I’m sorry to know the Heat Link of your Nest Learning Thermostat (3rd gen) stopped working. I appreciate the following information you have provided and the steps you’ve already taken to isolate the trouble. It’s a pleasure to help.

To assist you further, could you please provide the following details?

Did you see any error code on the thermostat or Nest app?
Was it installed by a Nest Pro or technician?
Did you notice any power cuts in the area before this occurred?

I appreciate your collaboration in this post @Frustratedddd.

Any additional details you can provide will be helpful.

Regards,

Daniel

Re: Heatlink stopped working

cunninghamb017 — Tue, 02 Dec 2025 01:32:18 GMT

Did you see any error code on the thermostat or Nest app?

Was it installed by a Nest Pro or by a technician?

Technician , over 5 years ago.

Did you notice any power cuts in the area before this occurred?

Re: Heatlink stopped working

moralesvicente — Wed, 03 Dec 2025 02:13:59 GMT

Hello @cunninghamb017,

Thanks for getting back to me and sharing this information. To continue addressing the issue, please follow these next steps:

Use the Nest app to call for heat or hot water and wait for a click from the Heat Link.
Perform a click test on each relay individually to identify if one or both relays are stuck in an 'always-on' or 'always-off' position.

Please let me know how it goes.

Regards,

Daniel