No 12V output from Nest Heat Link, H72 error code on display

[Maurice1962]

Heating did not work this morning.  Display gave me the following error 'HEAT LINK The power to this thermostat is off. Learn more at nest.com/h72.  I have it 'wired' such that there is a 12V output from the heat link to the wall mounted controller.  There is 220 volts onto the heatlink, but there is no 12V output to the controller.  Can it be resolved, or do I need a new heatlink?.  Appreciate any help.

[george_t]

Hi @Maurice1962,

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

Also, please answer to 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.)
 

[Vladut]

Hi there, just checking in with you. Did you have the chance to check the above message?

[george_t]

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.