Nest 3rd Thermostat Heat Link

[#1]

Hello

Up until yesterday, my 3rd Gen Learning Thermostat was working fine.  As of today it has the error code H72 and states there is no power reaching the thermostat. 

Having troubleshot online I have narrowed it down to the heat link box failing.  Nothing has changed overnight to the set up so the box seems to be the issue.  

Any suggestions?

Thermostat less than a year old 

[Gooner5955]

Same issue here with gen 2, seems new heat link is the answer 

[AnaM]

Hey @ and @ ,

I'm sorry to hear you're experiencing this issue, but I'll do my best to sort this out for you. Please answer thr following questions so that I can properly document and isolate this issue:

1. When was it installed?
2. Did the issue happen during installation or after installation? Was it installed by a Nest Pro or by a regular installer?
3. 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?
4. Have you had any recent power cuts in your area? If yes, has the power been restored?
5. Have you recently had service or maintenance on your electrical, plumbing, or heating system?
6. Have you tried any troubleshooting steps before contacting us?
7. How many thermostats do you have?

[AlexD]

Hi, I wanted to check in. Do you need any further assistance? If so, make sure to let me know. 

[CristianC]

Hey there. It's been a while since this thread was last updated so I'll go ahead and lock this thread. If you're still experiencing problems, please feel free to start a new thread and we'll be happy to help.