Woke up this morning to a cold house, heating didn't turn on, looked at the thermostat and initially it said it was low on battery which I found strange as it's powered on the wall. After removing it off the wall and manually charging it for a bit I then put it back on the wall and was greeted by a H72 error code. Reading around here and on Google, done some troubleshooting and now the error code is no longer present on the thermostat and now it just displays a picture of a heat link in the thermostat screen.
1. It was installed roughly 3 years ago.
2. I first noticed it this morning.
3. It was installed by an electrical engineer.
4. I noticed initially a dead battery message, then a H72 error, then a image of a heat link.
5. Had a power cut about 5 days ago, but been working fine until tonight.
6. No maintenance done recently, only a boiler service about 6 months ago.
7. I have only one Nest Thermostat
