Lennox Mercury to Nest

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frankstallone

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Bought a home with a nice HVAC setup. Everything is fairly new expect, what looks like, the original Lennox mercury based thermostats. I wanted to replace them with Nest Thermostats and have, but I am not 100% sure I got it right. Let me tell you what I have, upload some photos, and let me know what you think. I confirmed with Nest that their thermostats will work with the setup I have. Also if you think there's a better place for me to post this question, feel free to reach out and let me know.

* HVAC Setup *

** Larger Unit **

LENNOX ELITE XP13-036-230 - 3 TON, UP TO 14.2 SEER / 8.5 HSPF, 208 / 230 VOLT, SINGLE PHASE, R410A HEAT PUMP.
CBX27UH-042, Upflow/Horizontal, Air Handler, Multi-Speed, 3.5 Ton, Elite Series

** Small Unit **

LENNOX ELITE XP13-024-230, Heat Pump, 13 SEER, 2 Ton, R-410A, Elite Series.
CBX27UH-030, Upflow/Horizontal, Air Handler, Multi-Speed, 2.5 Ton, Elite Series.

The Lennox thermostats have _no_ model numbers. The best I could find was a sticker with LR1620 on it but Google only finds Honeywell thermostats with that number. Calling Lennox was no help. They told me to call a Lennox Certified Dealer.

Both thermostats have the same wires run to them (this is at the furnace):

** @ Furnaces **

R - RED,
R - ORANGE,
G - GREEN,
C - BROWN,
Y1 - WHITE,
W1 - YELLOW,
O - BLUE

Then there is another wiring loom that goes to the same motherboard out to the heat pumps. For instance, R is jumped to the RED cable that goes outside.

** @ Nest thermostat **

Y1 - YELLOW,
G - GREEN,
OB - BLUE,
RC - RED,
W2 - WHITE
C - BROWN

** Photos of Thermostats **




 

frankstallone

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** Photos of 2 Ton Units (Continued)**



-- This last photo I am holding the loom going to the thermostat

** Photos of 3.5 Ton Units **



-- Only one photo because they're mostly the same, wiring wise.
 

slownsteady

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I'm 98% sure that is a honeywell tstat just branded by lennox, so i would be pretty confident on the info you can find in the Honeywell owner's manual.
As for the Nest Tstats, I'm not qualified to answer.
 

frankstallone

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Thanks slownsteady! I was able to get outside and get the wiring from out there. Both units have the same wiring:

** 2 Ton XP13-024-230-03 **
** 3.5 Ton XP13-036-230-03 **

W1 - White
C - Black
R - Red
O - Blue
Y1 - Yellow
 

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