Help! Cant turn heating on....

[Johnctebb]

Help, first time trying to get the heating on. Nest thermostat says its on, but nothing happened at the boiler?

[CoolingWizard]

Johnctebb, can you provide a little more information that would help me to help you best?

Has your nest thermostat been installed and operational in previous winter season‘s when you were turning on the heat?

You say you have a boiler, do you also have an air conditioning system controlled by the nest?

Did you install this Nest Thermostat or did someone else install it?

your statement says this is the first time you’re trying to use heat so we might need to verify the installation is why I ask these questions.

I am looking forward to helping you. 

Ken

[Johnctebb]

New install this summer, new gas boiler and replaced some radiators, we installed nest as the installer didn't know anything about nest. We are using the hot water functions all ok. The heating ran ok on install, but not from the nest thermostat.

The thermostat says its working but nothing happening at the boiler?

Would turning the hot water on also start heating on?

[CoolingWizard]

What you have is what’s called a COMBI-Boiler heating system. Your boiler does a combination of heating water as well as heating water separately for your radiators and baseboard heating systems.

in all likelihood your nest thermostat software was not set up properly to identify the heating system as a separate heating system. And I am saying this because you stated that when it was installed before you had the nest installed the heating system worked. And after the nest was installed you now find that the heat is not working. 

Now what you need to understand is that the heating system has a separate set of control wires from that of the AC cooling system. That is you will have say a red wire coming from the cooling system attached to Rc and typically a red wire coming from the heating system connected to Rh.  The wire to turn on the heat should be in the W connector on the backplate. 

For heating, the Nest thermostat connects Rh to W to initiate a call for heat.  For cooling the Nest thermostat connects Rc to Y and G to initiate a call for cooling. 

Can you take a picture of the backplate and the wires and upload it please?

Ken

[Johnctebb]

Installer just called, asked to press button on white control box to go "manual" and both the heating and hot water now running. Will get engineer out to look at the connection you have highlighted, everything is still under guarantee. Thanks for you replied

[Johnctebb]

Incorrect wiring of the comms box, hot water satisfy in the wrong return place.