Nest thermostat on Valliant combi boiler

JonnyH2

Hi,
I'm trying to install a 3rd gen nest thermostat with my Valliant combi bolier (831 plus).
All works well except the hot water can only be used when the heating is on.. i.e it doesn't seem to operate independently on demand.. 
Any ideas what I might have wrong?
Thanks for any help.

Jeepers_Creepers

That sounds weird since - as you clearly know - the DHW should be completely independent of the CH, and even over-ride it when both are asked for. 

Could you post some close-up photos of the wiring you made to the boiler, along with ID'ing these wires from the Nest if not obvious? 

jefaz07

To be honest I don't think these threads should be allowed to continue. Yes its money saving but we shouldn't be encouraging people to interfere with boiler seals and combustion without the necessary checks made afterwards. 

Jeepers_Creepers

It's a wiring jobbie, Jefaz. The worse that'll happen is that he 'cutes himself.

Darwinian, innit. :-)