Heatlink is dead, thermostat shows H72 error code.
I have read the other links and carried out procedures as advised but no luck
Does anything happen if you press its button for 30 seconds? Nothing
In some cases the boiler will have an additional isolation switch which can turn off the power to both the Heat Link and the boiler. Can you try switching that off/on again to see if anything changes? Done – no change
Make sure the breakers are on or the fuse board hasn't tripped. Reset everything – No Change
Moreover, to have a better view over each of your cases, please help us with some answers:
How often do you experience the issue? Once
How long has your thermostat been installed for? About 18 months
What colour is the Heat Link LED? No Lights
What is showing on the Nest thermostat display? H72
Have you had any power cuts recently? No
Have you had any work done on your electrical or heating systems recently? No
How many zones are present in the setup? Two (second zone is running on a separate heatlink and is fine)
Is there power present to your boiler? Yes
