New Heat Pump Thermostat Wiring Question

Old 09-15-04, 10:01 PM
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New Heat Pump Thermostat Wiring Question

I have a Lennox system, cooling unit model 12HPB60-2P, indoor heat unit 80UHG (Gas). Was told it is a heat pump system, running with a Robertshaw therstat, mod 300-208. Wiring is followed (has been there when I moved in): White - W1, Yellow - Y1, Green - G, Red - 24v, Blue - 24v(c), Orange - O, a jumper connects R to 24v, and No wire connects to B (open).

Now, I want to replace with a Honeywell. Got one, model T8611G2051 Chronotherm IV Plus but the wiring instruction seems to confusing. It is for zoning, TotalZone or EMM-3U. I am not sure which wire go with which terminal. The terminals on T8611G2051 are:
- in one row: OC, C, OT, OT, L
- in another row: R, W2, OC, E, Y, O/B (one term), G, a jumper connect E and Y (it is there out of the box).

This is my first time with thermostat and I seems the technology is a bit beyond me. I would appreciate your help (I read Ed's reply to another similar question but I still do not understand fully yet). Thanks. Andy
Old 09-16-04, 01:33 PM
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red to r
blue to c
white to W2
yellow to y
orange to o/b should be an o/b switch, put it in "o"

check the instructions, on that jumper, be sure you set it up for "dual fuel"

this is what you have wire-wise now

red is 24 volts power
blue is common
orange is reversing valve, energized in cool (b is energized in heat)
white is second stage heat, in your case gas
yellow energizes the compressor (if y is energized, cooling. if not, it will heat)

either you MUST have a dual fuel board at the furnace or this MUST be a dual fuel tstat. this is because you NEVER want both gas and heat pump (both heating stages) running at one time.
Old 09-17-04, 09:32 PM
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Thanks. Your wiring instruction is clear enough. I will try to connect just like that this weekend. As to the jumper, as I found it out of the box, it connects E and Y. I looked up all document from Honeywell but found only some notes on the jumper applying to TotalZone (Don't know what that is). Should I just leave the jumper like that?

Again, I really appreciate all the help.

Old 09-22-04, 02:21 PM
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That OT OT there is if you have a outdoor temperature sensor.

Old 09-24-04, 09:42 AM
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Thanks. Understood the OT. I do not have outdoor thermometer. I just concern with the jumper connecting E and Y. I do know what to do with it. Leave it alone? Remove it? Or connect two other terminals together?

Thanks. Andy

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