Nest 3rd Generation Thermostat

[Sarah3]

Hello - my Nest 3rd Generation Thermostat Heat Link - purchased March 2020 - suddenly stopped working. I'm hugely disappointed that there is a problem with this (expensive) thermostat after only 27 months!  An engineer has been to my home and the problem is with the Heat Link device itself.  The thermostat and electricity supply are both absolutely fine.  I need to replace the Heat Link.  How can I purchase just that part (heat link)?  This seems to be a common fault - reading through this community - and yet replacing just the faulty part is challenging.   It doesn't make sense (cost-wise or environmentally) to replace the whole thermostat.  There should be very clear information on google's website on how to purchase this part if it breaks so often!

[Nestnomore]

Good luck finding replacement parts for the Nest Thermostat. My base died the other day and Google has already given me the "sorry, no replacements" message. Since I am out of warranty (device is 2 years old), they will not sell me a replacement for the base so they just gave me a link to their online store and suggest I buy a new one. 

[DragosC]

Thanks for letting us know  @Sarah3

We're sorry to hear that. No worries. Help's here. 

Could you tell me please when did the situation start occurring first and when was the thermostat installed?

Also, please answer the following questions:

Are there any lights on the Heat Link? Does the boiler activate when calling for heat by pressing the Heat Link's button to activate Manual Mode?
Are you seeing any wiring report or error on the thermostat and/or the app?
Have you had any recent power cuts in your area? If yes, has the power been restored?
Have you recently had service or maintenance on your electrical, plumbing, or heating system?
If yes, how long was the power off for? (Be specific.)

Could you tell us please if you've checked on the breaker switch and fuse box?
Any blown fuse in there? Have you tried to turn the breaker switch off and on again? Any difference?

[Sarah3]

Hello Dragos,

A certified engineer was here yesterday and he checked out everything (boiler, electricity supply to the Heat Link, fuses).  His conclusion is that the Nest Heat Link is dead. He has seen this before.  The thermostat works and the error message is H71, which means it can't connect to the (dead) heat link.  My email was written after the engineer's visit, and we checked everything out.  The combo-boiler is fine and produces hot water easily and heats the house when controlled from the boiler (engineer checked this, too, and completed the boiler's annual service).  The boiler is 100%, the fuses are fine, there is electricity in the circuits going into the heat link (he checked the wires connected to the heat link).  Simply, the Heat Link is dead - no lights etc..  

The problem appeared when I was away on a short trip mid-June.  Since none of my other appliances had blinking lights, which would be expected following an electricity outage (neighbours confirm there was no outage), I conclude there has been no outage.

Ergo - the Heat Link is broken.  I'd like to buy just a Heat Link, not a whole new thermostat set up.

Thanks,
Sarah

[DragosC]

Thanks for the detailed description. We've sent you an email. Please check on it and follow the instructions. Let me know when you're done. 

[Sarah3]

Done!

[DragosC]

Thank you so much for helping us diagnose this issue. From this point on, we'll set up a replacement for your unit. It looks like your area is covered by our installation partner BOXT, who offer next day installation services. We can send you the information required to book your replacement device with them; please note that choosing this option will require a credit or debit card only as part of the booking process, but no charge will be applied. Please check your email for more details.  I'll have to close this thread. Should anything else come up, please open another thread and we'll take it from there. Have a good one and stay safe!