# HVAC Issues after replacing Thermostat



## rodwade (Feb 13, 2007)

My new thermostat did not have the same wireing as the other. I did this about 7 months ago when we moved in. The AC didn't work at first, but I swapped around two wires and it came on. Now I tried to turn the heater on for the first time and nada, no fan nothing. I have a honeywell Tstat. Wired as such.

RH-Blue Wire: which leads to one side of a ceramic resistor looking device in the air handler with another Large brown wire
RC- Red Wire: connects to high water switch in Pan
W- White wire: connects on opposite side of ceramic resistor with another large white wire
Y-Yellow wire: runs to outside unit.
G- Green wire: connects with large gray wire.


Help it's freezing down here!


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## rodwade (Feb 13, 2007)

some additional info

The blue wire connects to a brown wire in a twist crimp, also attached is another smaller gage wire which is one of two wires (other is yellow) which run outside to the compressor unit.


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## rodwade (Feb 13, 2007)

Yellow wire goes straight outside it doesn't go into the air handler wiring

Model number on CARRIER Ac fx4cnf036


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## knowphish (Jul 10, 2008)

If you switch the fan to the "on" position, will it come on?


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## rodwade (Feb 13, 2007)

yes it would. Seems the original installer installed a common wired through a resistor which wasn't on the wiring diagram. Caused some problems. Called a local company to come take a look. He snipped the wired it up as a 4 wire and it was done/


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## xtreme (Jan 9, 2010)

programmable thermostat?
Not all A/C units are compatible. I think (not sure) some need a transformer


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