How to wire Trane heat pump to Google Nest

[yahoo]

I saw some similar posts, I think the below link from 22 is the closest.  I currently have 7 wires on my heat pump and appears I only need 6 connectors for Google Nest thermostat.   I have connectors Y2 (brown), W1)white), R(red), O(orange), Y(yellow), G)green), B(blue) on my current trane thermostat.   I do have auxiliary heat installed for my heat pump.

if I follow the prior advice, it appears my Y2 (brown) write might be extra... can I simply tape it off and still have all functions including aux heat?

https://www.googlenestcommunity.com/t5/Nest-Thermostats/Nest-thermostat-compatibility-with-Trane-Hea...

Thanks

Michael

[Patrick_Caezza · Accepted solution]

@yahoo 

Y2 is 2nd stage cooling, not Aux heat. If you tape it off, you won't have 2nd stage cooling.

The W1 wire is the Aux heat, and if you tape it off, you won't have any Aux heat.

You need the Nest Learning Thermostat, 3rd Gen, to maintain all of the functions your current thermostat has

[yahoo]

Patrick,  I am interested to buy a 3rd generation.   I now found there is a compatibility checker, but it says to post a photo of my current thermostat.  I also found video of 3rd generation install which is helpful, how would I connect my wires to a 3rd generation?

[yahoo]

I now have a 3rd generation thermostat in my hand.   I see that it has connections for Y2, W1 and G.  How should I connect  R, O, Y and B?

[yahoo]

Thanks, that was very helpful