A lot of back-story, but I’m not sure which bits are important.
I noticed today that my air-conditioning wasn’t working. The thermostat said the AC was running, and the furnace blower was blowing air, but it wasn’t cold. After futzing around a bit, I checked the outside heat-exchanger, and its fan wasn’t running. There was a humming sound coming from it, so it had power.
I unscrewed the cover, which the fan is attached to. I pulled the cutoff out from the electrical mini-box out by the heat exchanger. I don’t know the term, but it has copper blades, and cuts power to the AC fan, at least. With the cutoff removed, the humming mostly went away, but there was still a little humming, so there was at least some power.
I lifted the cover, and the fan blade rotates freely. The casing for the motor was hot. Inside the heat-exchanger unit, there were some wires, and a big capacitor (about 2 inches diameter by 4 inches tall). I wiggled the wires a bit, carefully, and the remaining humming would vary a little bit.
I set the cover back in place, and re-inserted the cutoff. The fan rotated a little, maybe 20 degrees, then stopped. The loud humming resumed. I tried removing and re-inserting the cutoff, with the same behavior again.
Any ideas? I’m guessing the motor has gone, and it’s just time for a service call, but I’m not a motor expert, so is that probably the case? The compressor would be the main load, though, and the cutoff would presumably cut power to that. If the fan power wasn’t being cut, why did it rotate when the cutoff was replaced? If the fan power was being cut, what still had power with the cutoff removed?
Is there anything I can try, even if it would only work a day or two? Otherwise we’ll live with no AC tomorrow, and call for service on Monday, to avoid the weekend rates.
I have an electrical service question also. I flipped the AC breaker to off, and noticed my stove went off. It turns out that the Stove and AC breakers are mislabeled. The AC breaker (labeled “range”) is 50 amps, and the range breaker (labeled AC) is 40 amps. Do those numbers sound right, or could the breakers be swapped and it should be the other way around? If it helps to size the AC amps, my house is about 2600 square feet, and I live in SE Michigan. House was built about 15 years ago.
I would normally assume the breakers were simply mislabeled, but I found that they had wired two separate circuits together, so that both breakers had to be set to off to kill the power to the two circuits. (And I’m the first owner. I bought from the builder.)