I just bought a house with Central AC. I tested the unit initially and it worked fine. I just turned it on and the outside condensing unit is not coming on. I went out to look, and I see a white wire that is taped to the insulated pipe coming out of the house, and the wire goes to nothing - just wound loose around a pipe near the outside unit with 2 bare wire ends. I can only think that maybe someone cutting the lawn or trimming maybe pulled the wire out or cut it - but I don't know what the wire is and if it should go somewhere. How can I trouble shoot this? The thermostat brings the blower fan on, but not the outside unit to cool.

Thanks for any help...

Is there any other "small wires" from the house going to the unit? There needs to be low voltage from the furnace to the contactor on the outdoor unit. With the power off, take the cover off the A/C and see if you can tell if there are any wires broken or pulled loose.

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Originally Posted by jmdphoto

I just bought a house with Central AC. I tested the unit initially and it worked fine. I just turned it on and the outside condensing unit is not coming on. I went out to look, and I see a white wire that is taped to the insulated pipe coming out of the house, and the wire goes to nothing - just wound loose around a pipe near the outside unit with 2 bare wire ends. I can only think that maybe someone cutting the lawn or trimming maybe pulled the wire out or cut it - but I don't know what the wire is and if it should go somewhere. How can I trouble shoot this? The thermostat brings the blower fan on, but not the outside unit to cool.

Thanks for any help...

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It looks like that's the only wire coming from the furnace. The other wires are in the big bunch going to the outer power box. Do I need to disconnect that, or just switch off the AC breaker inside, or doesn't it matter? Didn't get a chance to open the condenser up due to rain today, but will it be obvious where this wire connects if it is the contactor wire?

Yes, you should be able to see where they were pulled loose, it doesn't really matter how they are hooked back up, just make sure they are both connected, there should be two small wires in the unit near the electrical area. You can either shut the power off at the disconnect next to the unit or at the breaker inside the house, just make sure the power is off before you remove the cover.

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Originally Posted by hvacservicetech_07

Yes, you should be able to see where they were pulled loose, it doesn't really matter how they are hooked back up, just make sure they are both connected, there should be two small wires in the unit near the electrical area. You can either shut the power off at the disconnect next to the unit or at the breaker inside the house, just make sure the power is off before you remove the cover.

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Yes! Back in operation! Thanks for the advice!

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