Wiring Help

Old 07-02-15, 07:21 PM
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Wiring Help

Hello All,

I need some help with wiring my new thermostat. The old thermostat is a Lux Pro DHP2120, the new is a Lux TX1500Uc. The air handler is a Lennox CBX27UH, but I do not know about the outdoor unit (I am a renter). I do know the system is 2 stage heat, 1 stage cool, and also a Lennox.

There are 7 wires in the wall.

Here is the old configuration:

C, W2, B/O (functioning as B per a circuit jumper on t-stat), R, G, E, and Y1.

Per the t-stat instructions, I wired the following: C from old thermostat to C to new thermostat. W2 from old thermostat to W2 to new thermostat. B/O from old thermostat to B to new thermostat. R from old thermostat to RC to new thermostat, jumper from RC to RH. G from old thermostat to G to new thermostat. E from old thermostat taped off on new thermostat and not used. Y1 from old thermostat to Y to new thermostat, jumper from Y to W1.

When I call for cool, I get heat. I am not sure if any of the t-stat instructions are correct for my unit now.

Any help would be great. THANK YOU!
Old 07-02-15, 08:36 PM
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Welcome to the forums.

I sure hope you have the landord's permission to change the thermostat.

You should put the reversing valve wire on O not B. Lennox powers the valve to cool.
Be sure to turn off power to air handler when working on stat wiring.

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