nest thermostat not activating central heating

[Chris-H1711]

Ok, so if you’ve nowt on the orange with demand, and it’s definitely receiving voltage from the heatlink, then your ZA5 is kerput.

Ok, just so i understand what is going on, the valve is opening when it receives demand, but i am assuming it is not returning the signal to the boiler or pump to turn on?

Would you say this is related to the change of pump? I assume its just a coincidence that they have both gone around the same time?

 

[Deleted member 120897]

Yep that’s what’s happening, the valve can open, but if it doesn’t make the microswitch or the microswitch has failed the the voltage won’t be delivered to the pump and boiler. Coincidence they’ve gone at the same time.

 

[Chris-H1711]

Yep that’s what’s happening, the valve can open, but if it doesn’t make the microswitch or the microswitch has failed the the voltage won’t be delivered to the pump and boiler. Coincidence they’ve gone at the same time.

Spot on, thanks so much for the assistance

 

[Chris-H1711]

Ok, so if you’ve nowt on the orange with demand, and it’s definitely receiving voltage from the heatlink, then your ZA5 is kerput.

This was indeed the case, picked up a new zone valve from screwfix, installed and the heating is now working as it should. You have saved me a fortune in a callout, so an enormous thank you to you