Nest thermostat - Room Stat?

[Midd_2005]

Hi All,

I’m having some building work done and plan to swap my Honeywell ST699 to a nest thermostat following the work. One question I have is regarding the room stat I have in my lounge. Is this needed following the nest installation?

If I was to disconnect the room stat now before I install the nest would this cause any problems?

I just want to ensure any work like this is done prior to any plastering I have done.

Thanks

 

[stem]

The Nest Heatlink will replace the existing ST699 programmer and the existing thermostat should be removed to prevent it interfering with the operation of the Nest.

However, if the thermostat is just disconnected, the heating wiring will be 'open circuit' and the heating will not operate. So it should be decommissioned properly. This can be done by tracing the wires back from the existing thermostat and finding where they originate from. Then disconnect them at their origin, and the two terminals where the thermostat switching wires came from should be joined together. Any neutral, if present can just be disconnected.