Looked at the contacts and they appear darkened but not fused together. I can press the spring and it moves freely. Contacts measure open at rest and shorted when I press them, so all seems ok there. That was my first suspicion as well, because as I said, the A/C is set to off at the thermostat, and the ontactor does not activate, so this fan should not be coming on.
I am new to JustAnswer. For my $30, are you going to stay with me until I get this working?
Have schematic in front of me.
The only circuit board is labeled "Circuit Board," not "Defrost Board," but it does contain the Defrost Relay and Circuitry, so I will assume this is the right one. Wiring from this board leads to the Defrost Thermostat and the Reversing Valve Solenoid among other things.
I will disconnect the low voltage wires, apply power, and see what happens. I see high voltage lines connected to the defrost relay, I will not be disconnecting those as per your instructions.
Will report back shortly...
Breaker still trips.
Point of confusion on your comment. You said "What we are doing is seeing if this board is allowing voltage to go to the fan.It should not be."
The Defrost Relay is depicted as a normally closed relay. I measured 0.0 ohms across the contacts. That tells me that it IS allowing voltage to go to the fan, unless the logic circuit tells it otherwise, which it won't because we disconnected all the low voltage.
Am I correct?
Will stand by...
Inside temperature 79 degrees...
Don't have a clamp on, wish I did. My handheld is rated 20A Max Fused. The breaker that is tripping is 30A, so I'm thinking if I put my handheld in series, the meter's fuse will go before the breaker.
Besides, I think it trips to fast to take a measurement.
Note that there are three breakers feeding my A/C, which I thought was kind of weird. Two double pole 60's and a double pole 30. It's the 30A breaker that is tripping. I traced it out and it goes to a 30A breaker in the A/C unit in the house, and to the condensor outside. Disconnecting the condensor stopped the tripping.
When I first started troubleshooting, the fan would turn for about two seconds with a wierd growling/grinding kind of noise, then the breaker would trip. Now it trips instantly.
Powered off, the fan spins freely with no grinding or other weird noises.
Can't see any windings, the unit is completely sealed. I guess anything other than that would have surprised me, being exposed to the elements the way it is.
I disconnected the leads to the fan motor and measured them. Here's what I got:
Yellow to Black = 43 ohms
Yellow to Brown = 76 ohms
Brown to Black = 33 ohms
I would expect those numbers to all be equal, but again motors are a weak point for me.
The schematic depicts this motor as a circle with two windings in a V shape with Black being common. Not sure if that means anything.
OK. Hooked all the low voltage back up. Disconnected the yellow wire from the fan to the contactor. Threw the disconnect switch and heard a strange sound for about 1 second, then the breaker tripped.
Sounds like the compressor can't run.
What I don't understand is, why is it trying to? The thermostat in the house is set to OFF.
Compressor is kind of hard to get to, so I found the C, R, and S designations on the schematic and disconnected the wires at the other end. Two from the contactor and one from the capacitor.
All wires measured short to the copper tubing. One measured about two ohms, the others were dead short.
I take it from your comments that the compressor is shot. (Bizarre, I just got through changing the compressor in my car!)
What I still don't understand is why it's trying to do anything when the thermostat is set to OFF?
Any idea what this will cost me, ballpark figure?
Anything else I can do myself at this point to save a few bucks?
Hello again, your test is most likely good, and the compressor is most likely burned out. If you can find the refrigerant charging ports and let a tiny bit of gas out, and onto an acid test strip you can get at the drug store...and it tests acid it is burnt for sure.
It is not always a good idea to replace a burned out compressor if the unit is more than 5 years old... tell me how old the unit is we can go from there.The thermostat issue can be checked by checking voltage between the two coil wires that operate the contactor... if you have 24 volts there when the thermostat is off there is a problem with the thermostat, or a shorted wire on the way to the thermostat or elsewhere.Let me know what you find, we can go from there.Phil
No voltage on the contactor coil. Contactor never activated when applying power.
Unit was used when we bought the house 5 years ago.
Will my heater still work?
Ok, removed the electrical connection from the compressor itself. Readings are as follows to copper tubing:
Heat works fine. Now it's 82 in here!