Nest Learning Thermostat Wiring Confirmation

[jdrplus]

Hi all,

I've just installed four Nest Learning Thermostats and want to confirm the wiring configuration. The main question focuses on the W2/Aux wire from my previous thermostat, which was a Honeywell Home Pro Series T4.

Here is the previous configuration:

For clarity on the labels that are obscured by the wiring, "O/B" is the label behind the orange wire, "Aux" is the label behind the white wire going to W2, and "E" is the label behind the black wire.

My understanding is that my system consists of a Lennox heat pump (ML14XP1-030-230) and a Lennox air handler (CBA25UH-030-230).

Based on the original wiring configuration, I wired the new Nest Learning Thermostats as follows:

My main question is whether the white wire going to the W2/Aux should be connected to the W1 instead, but I want to confirm the wiring configuration as a whole.

My question stems from using the wiring configuration setup in the Nest app which indicates two different wiring setups based on if I identify the white wire as "W2" or "Aux" since there isn't a option that lists them in combination.

Nest app suggested setup #1:

Nest app suggested setup #2:

Let me know if you have any questions. Thanks for your help in advance!

[EdmondB]

Hello mshorey81,

Thanks for posting here in the Community. Based on the photos of the wires from your current thermostat, this is a heat pump system with 2nd stage heating and Emergency. This should only be compatible with the Nest Learning Thermostat 3rd Gen.
The correct wiring configuration for that in the Nest thermostat is the following:

1. Yellow wire on Y1
2. Red wire on RC or RH
3. Blue wire on C
4. Green wire on G
5. Orange wire on O/B
6. Black wire on Asterisk
7. White wire on W1

Take note that white wire is the 2nd stage heating wire, so it will have the same role even if you put it on the W2 terminal. 

Let me know if you have more questions.

Thanks,
Edmond

[jdrplus]

Great! Many thanks for your response. I'll plan to keep my wiring as-is based on the information provided. The Nest is recognizing the wire in W2 as auxiliary heat, or 2nd stage, so it seems good to go. Your help is much appreciated!

[EdmondB]

Hi there,

Sounds like a plan, I'm going to mark this one as resolved. Please feel free to open up a new thread if you need assistance.

Best,
Edmond