Wiring help - Q674L 1132 to RTH7400 - http://www.hvacmechanic.com/ Forums

Original message

Fournier

70.80.63.251

"Wiring help - Q674L 1132 to RTH7400" , posted Mon 25 Aug 23:29

Hello,

I need to replace my old thermostat (Q674L 1132) with a new Honeywell RTH7400. The wire used were W B G R O Y. X was not used. I have a heatpump with em. oil furnace. Could help me out? Thanks in advance!

Replies:

Houston204

98.196.66.53

"Re(1):Wiring help - Q674L 1132 to RTH7400" , posted Tue 26 Aug 22:24

Color codes vary, especially common. Remove power to the fancoil and write down your existing Terminal = Color combination before replacing your stat.
Your old B = C
W = Aux & E
G = G
R = Rc & R
O = O/B
Y = Y

You must also configure it for heatpump operation.
option 170 = 7
190 = 0
240 = 5

If you do not have a seperate fossil fuel kit I recommend the Visionpro TH8320 with optional outdoor sensor.

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