Nest Learning Thermostat 3rd Gen - app / thermostat / main boiler not responding

[Peanut2025]

Our system does not communicate across the app, thermostat and boiler. I have reset / overhauled the system (i.e. app delete / restart, re-paired heatlink and thermostat etc etc multiple times. The heating turns on when the thermostat says 20 degrees and the app schedule is set at 16 degrees. The heatlink is also not responding to manual instruction i.e. the heating will be "off" on the heatlink but the radiators are on. Do we need to get a specialist in? 

[sultanali858]

It sounds like this may not be an app or sync issue, since the heating is running even when the Heat Link shows off. If the boiler is still firing without a call for heat, it can sometimes indicate a wiring issue or a fault with the Heat Link itself.You could try lowering the temperature fully and using the Heat Link button to see if the boiler responds. If not, it may be best to have a qualified heating engineer or Nest installer check the setup.

[Frustratedddd]

Start from the basics, forget the app for a while.

What lights do you have on the Heat Link?

Does the boiler fire up when you call for heat from the display. Then does the boiler turn off when you drop the setting back on the display?

Are you saying the boiler will not fire up when you press the Heat Link button?

Do you have motorised valves fitted in the system?