Nest thermostat runs only in manual mode for heating

[bbbiby]

The thermostats have been working fine till this morning. When I try to turn the thermostat up, it turns orange as expected and there is a "click" on the Heat Link. However nothing happens on the boiler. The thermostat then sits showing the room temp "18*C" and the desired temp "21*C" as if it is working away correctly. This is also shown in the app on my phone too.. The same circumstances happen when I use the app to change the temperature... Both app and thermostat update each other but do nothing to the boiler.

The home link when ran in manual mode, works absolutely fine. I can press the button and it fires the boiler without any issues. So at least the house is warm.

I have seen no error codes and have restarted both the thermostat and Heat Link to no avail. This is a wire connection btw, and the heatlink shows all three lights as green when in manual mode as well.

Unsure what to do here. Any help?

[bbbiby]

@Josemaskil and @Frustratingnest my electrician did a few checks yday, and we re taking it baby steps. it seems that 2 eph valves MAY be not working as expected so next week the plumber will come to change. I will let you know if that was the problem or something else needs to get checked or changed. 

[Frustratedddd]

The easy prove is as mentioned, check the relays. That will then prove if the Nest is working correctly.

You can then eliminate the Nest part before you start.