Replacing Horstmann Centauplus c17 with Google Nest. Wiring

[Userjb40]

Hello,

I've currently got an air to water heat pump being controlled via a Centaurplus c17 series 2 with Honeywell thermostats in every room.

I'm looking to replace the Centaurplus with a Google Nest Learning Thermostat 3rd Generation.

I'll attach photos of internal wiring diagrams and what's currently wired

Any help greatly appreciated

Kind Regards

 

[CBW]

Almost identical wiring - Centaur to Nest heatlink as follows:

N to N
L to L
Link L to 2 (small brown wire)
4 to 3

When you say Honeywell thermostats in every room, do you mean trv’s?

 

[Userjb40]

Thanks

we have honeywell home 1 channel wired mechanical room thermostats in every room