In serious need of some HVAC help

chadly

Registered
Its the unit at the soon to be "mine" house, not the mark.

Its a goodman 3 ton unit, 3 years old. As soon as you apply power, even with the thermostat off, the fan starts to move slowly and then it trips the breaker. If you unplug the compressor it doesnt trip and will move air throughout the house, but of course it wont be cold sincce the comp isnt running.

My gut instinct tells me its something in the wiring. Something is shorted out somewhere. The electric company has a box they put on it so they can turn it off during peak hours if you choose to let them. Maybe they F'd it up doing that, I dont know.

I am open to any suggestions if you have any to give. I am currently searching for wiring diagrams and might go back out there and do some trouble shooting. My first time working on a heat pump.

Luckily the house is big enough to use 2 units so 1/2 the house gets cool.
 
I thought that at first but then realized that the thermostat was set to off, so it shouldnt have even been trying to turn on. Would that matter?
 
The kid says it could be anything, need to test it all. He's being no help, he believes he is "above" residential HVAC. ;)

Oh, did I mention he's union?

If you have specific questions once you test things and want me to ask him, let me know.
 
I thought that at first but then realized that the thermostat was set to off, so it shouldnt have even been trying to turn on. Would that matter?

Yeah, after reading the original post again, you're correct. I don't think it should've been trying to start.

If the start circuit was wired incorrectly to try to start... hmmm... after thinking about it, it sounds like they could have the neutral switched with one phase?

Try identifying the neutral and phase wires. See if it has single or dual switch contacts. If you could find the wiring diagram, that would help.
 
Well there is an identical unit right next to it so I can compare it with a known good. Great idea. Thanks JP!
 
On my unit, there's the power, as well as a pair of wires that tell the compressor when to turn on and off. (these run to the controller mounted in the furnace inside) If you disconnect those wires at the compressor, and apply power, does it still try to power up (and subsequently trip the breaker?) That would at least let you trace it to a faulty compressor, or faulty wiring/controller/thermostat.

also. up here in Wisconsin, the fan on mine tends to get a little rusty over the winter, making for a fairly "stiff" initial start-up. (fan spins slowly, or not at all) drenching it in WD-40 gets 'er working right..
 
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