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JamesI, Property Manager
Category: Plumbing
Satisfied Customers: 1895
Experience:  I have installed new and maintained existing kitchens, bathrooms, and heating systems and even a swimming pool.
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I have a standard Honeywell Thermostat which has three wires

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HiI have a standard Honeywell Thermostat which has three wires plus earth going into it...Brown Going to No 1
Grey with Blue Outer Sheath Going to No 2
Black with Brown Outer Sheath Going to No 3I want to replace this with a NEST Thermostat, I know which bunch of connectors it goes to in the base of the NEST Thermostat but need advice as which coloured wire to put into which NEST connector.I have photo's of Honeywell Thermostat, still wired up and working Plus it's wiring diagram and Wiring diagram for NEST thermostat.Help neededCheersDave
Customer: replied 1 month ago.
I have uploaded pictures to help

Good afternoon, what version of the NEST thermostat are you using.

The black wire going to terminal 3 of the thermostat is your switched live, and the one you should connect to the NEST call for heat terminal, is this what your looking for?

JamesI and other Plumbing Specialists are ready to help you
Customer: replied 1 month ago.
thanks, ***** ***** that mean...
black wire goes to 3 on nest
Brown wire goes to L on nest
Grey/blue wire goes to N on nestDon't know what version of NEST it is, sorry
Customer: replied 1 month ago.
Thanks James, worked a treat :-)Dave