I have a Lenox (36G6901)heat pump thermostat 2 stage heat/1 stage cooling and I want to change it to a Honeywell RTH7500 7 day progammable. I have 9 wires in the box

Lennox thermostat
R=red wire
V=white
F=green
M=black
L=brown
A=orange
Y=yellow and red
E=no wire
X=blue

Quote:

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Originally Posted by jflfjfbf

I have a Lenox (36G6901)heat pump thermostat 2 stage heat/1 stage cooling and I want to change it to a Honeywell RTH7500 7 day progammable. I have 9 wires in the box

Lennox thermostat
R=red wire
V=white
F=green
M=black
L=brown
A=orange
Y=yellow and red
E=no wire
X=blue

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Here is your manual just in case you lost it.

http://customer.honeywell.com/techli.../69-2221EF.pdf

I see you have an unusual connection in the ( Y=yellow and red ) location. I feel you could have a issue or problem in that area and also other areas since the nomenclature was changed as far as the color of wires and landing location for the old thermostat as compared to the new. I included a diagram that contains old Lennox wiring code.

You or a HVAC repair person might have to do a survey as to where the wires actually connect on the indoor and outdoor unit and what colors are being used for what purpose. This is not a simple thermostat change because it needs more knowledge from someone ON SITE that can actually tell what is doing what in the control circuit

If all else fails Honeywell has a tollfree number on the instruction sheet that I posted from Honeywells web site and they might have some information for you since they deal with this kind of change over every day.

Quote:

---

Originally Posted by jflfjfbf

I have a Lenox (36G6901)heat pump thermostat 2 stage heat/1 stage cooling and I want to change it to a Honeywell RTH7500 7 day progammable. I have 9 wires in the box

Lennox thermostat
R=red wire
V=white
F=green
M=black
L=brown
A=orange
Y=yellow and red
E=no wire
X=blue

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Here is the wiring change over list