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View Full Version : "fan only" switch turns aircondition compressor on


charlieboyer
Apr 17, 2009, 12:50 PM
My outside airconditioning compressor comes on when I set the thermostat to "fan only". I was told by an hvac person the problem was probably the thermostat, so I replaced the thermostat, problem did not go away.

acetc
Apr 17, 2009, 04:59 PM
Probably a short between the green wire and yellow wire from thermostat to furnace or someone jumpered the "G" to "Y" at the furnace.

letmetellu
Apr 17, 2009, 07:06 PM
Disconnect wire from G terminal and try it again, this should tell you if you have a shorted wire with the Y terminal

charlieboyer
Apr 19, 2009, 02:29 PM
I disconnected g wire, and tested... fan didn't come on, neither did compressor.
What's next? (thanks for the information by the way)

letmetellu
Apr 19, 2009, 06:34 PM
If you disconnected the G wire at the thermostat and the compressor does not come on when the thermostat is turned to "fan on" that make me think that you have a wire sorted to another wire some where between the furnace and the thermostat.

With the G wire disconnected does the condenser come on when turned to AC?

charlieboyer
Apr 20, 2009, 01:24 PM
I never tested the a/c, didn't think about it! Was too concerned that the compressor was running. I put everything back the way it was, and discovered now, that the darn compressor was running at the same time the heater was running! I am guessing that is the new Hunter Thermostat... I am going to put the older thermostat back on and start over. For now, I pulled the circuit braker for the compressor, until I can find where the wiring problem is! Thank you!

Joshdta
Apr 20, 2009, 02:56 PM
Never buy hunter t-stats!!