AC not working
#1
05-18-15, 03:37 PM
Join Date: May 2015
Location: USA
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AC not working
Over the winter I installed a new thermostat. Everything went fine and the heat was working great. Now that it is summer time and it is time to turn on the air... it does not seem to work. It did work last summer, so I dont think there is anything wrong besides my wiring. Can you let me know what you see is wrong?
#2
05-18-15, 03:45 PM
Member
The Y terminal is the "control" line for the compressor/condenser (outdoor) unit. There should be 24VAC between the Y terminal and the C terminal when the thermostat is calling for cooling. Unfortunately, I can't read the labeling on the thermostat connections, so I can't tell if the wiring is correct or not. Did you change any of the wiring at the air handler (furnace)?
#3
05-18-15, 03:50 PM
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Thermostat wiring is as follows:
White - W
Yellow - Y
Green - G
Red - R
Blue - C
The only thing I changed on the furnace side was adding the blue wire to C. The blue wire was previously not used on either end.
White - W
Yellow - Y
Green - G
Red - R
Blue - C
The only thing I changed on the furnace side was adding the blue wire to C. The blue wire was previously not used on either end.
#4
05-18-15, 04:30 PM
Member
Do you have a voltmeter? If so, what voltage do you read between Y and C when the thermostat is calling for cooling? Nominally, you should be reading ~24VAC between Y & C.
#5
05-18-15, 04:50 PM
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I don't have a voltmeter (at least, not that I can find). I can hear the t-stat click when it is supposed to turn on...
#6
05-18-15, 04:55 PM
Member
Turn off the power to the furnace and remove the thermostat. Jumper the R, G, and Y wires together. Turn the power back on and see if the outside unit runs. If it does, it indicates that the thermostat is defective. There are separate relays in the thermostat to control the blower, heat, and cooling. While you're hearing a relay click, it's possible that only the blower relay (R to G) is closing.
#7
05-18-15, 05:11 PM
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With those 3 wires together, the AC Came on... Looks like I am in the market for a new thermostat! Thank you very much for your help, it is much appreciated!
