# Thermostat wiring



## hbarfield (Aug 16, 2010)

Need help to get my house cooled off. Tried to replace my old Honeywell T841A thermostat with a new Hunter 44860. I must have messed up the wires, as it wouldn't power up the system. I tried to reinstall the Honeywell, and it wouldn't work either, I think I have the wires screwed up. Is there any way to tell now what the correct wiring should be???
It's a Carrier 5-ton heat pump system with emerg heat.


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## kok328 (Aug 17, 2010)

It's pretty easy, the wires are colored coded to the lettered terminals on the thermostat.
R = Red
G = Green
W = White
Y = Yellow
O = Orange

If you didn't turn off the power to the A/C unit before changing out the thermostat, there is a chance that you shorted the transformer.
Another problem is that there could be break in the wire(s) at the thermostat.
Thermostat wire is thin solid copper wire and it is prone to breakage if handled too much.


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## budro (Aug 18, 2010)

i am an hvac novice but have changed a few thermos. i remember two that had a brown wire on the old one. i hooked it up on my first attempt and blew the transformer. i learned later to discontinue it on the newer thermo. not sure but think it had something to do with the heat. these other guys that are pros might enlighten you if you have that extra brown wire. i am guessing here and have to go to work. thanks, buddy


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