Thermostat set to off but boiler still running

[GWD1923]

Hi there,

My nest is set to stop heating at 20/21 but the temperature in the house is up past 23 and the boiler is still on. Radiators are very hot. 
I’ve checked the heat link and that does click on and off if I increase the temperature in the app (past 23) or below current temp.
So, if it’s not the Heat link does this mean there’s likely an issue with the boiler somewhere? What do I check next?

Thanks,

GWD1923

[Frustratedddd]

I assume you are saying the display is working fine, when calling for heat you hear a click at the H/L, and when not you hear another click?

Have you tried turning the display down to 9? Does the heating still do the same?

You could assume the display is working OK, but without testing the relays with a tester to see if they are indeed switching, very hard to say. I have had issues where the relays get stuck, and a full reset has sorted the problem out, but obviously you will have to set the Nest up again.