wiring rth7400 from lr69071 - http://www.hvacmechanic.com/ Forums

Original message

bainbridge

71.197.212.173

"wiring rth7400 from lr69071" , posted Mon 10 Nov 17:31

I'm pretty sure I've followed the manual's wiring instructions, but the new thermostat won't turn my heat pump on. What terminals do I need to have wired?

Bainbridge

Replies:

Houston204

98.196.66.53

"Re(1):wiring rth7400 from lr69071" , posted Mon 10 Nov 21:28

The lr number won't identify your stat. Post the Q674- ----number on your old subbase. A T87 number might also work.

Did you write down the existing terminal = color combination before replacing your stat?

You must also configure your new stat to match your system.
Option 170 = 7
190 = 1 for Rheem, Ruud and Weatherking.
or
190 = 0 for Carrier, Lennox, Trane American Standard, Coleman, and ICP heat pumps.

"Tip of the Day" Remember to remove power first.

bainbridge

71.197.212.173

"Re(2):wiring rth7400 from lr69071" , posted Mon 10 Nov 22:21

How about T841A 1563 for the old model? I labeled the wires according to the old stat before I disconnected them.

W2 = yellow
O = red
G = green
Y = white
X = black
R = blue

I appreciate your help--thanks a bunch--

Bainbridge

Houston204

98.196.66.53

"Re(3):wiring rth7400 from lr69071" , posted Mon 10 Nov 23:06:

https://keithspecialty.com/k/67-TAV.htm

Strange color combination. Sounds like a Lennox.

Aux & E = yellow
O/B = red
G = green
Y = white
C = black
Rc & R = blue

option 170 = 7
190 = 0

"Tip of the Day" Remember to remove power first.

[this message was edited by Houston204 on Tue 11 Nov 08:12]

wingnut_2u

67.60.53.231

"Re(4):wiring rth7400 from lr69071" , posted Tue 11 Nov 03:08:

y=White
aux & E & W2=Yellow
if you dont do this your strip heat will come on with air conditioning :)

[this message was edited by wingnut_2u on Tue 11 Nov 03:12]