AC quit a couple days ago. Inside fan runs, no DTCs flashing on the diagnostic light. Outside fan and compressor do not run. Outside fan only a couple years old, so I don't suspect it. After watching a couple videos, I decide to buy contactor, start cap, and run cap. Then I notice 1 of the bullet fuses in the outdoor disconnect is blown. So I replace them and turn the system on. Contactor pulls in and emits a hum / buzz, still no action from condenser fan or compressor. Called it quits for the night last night.
today after work I go downstairs to make sure any breaker marked AC or FURN is turned off. I see a sticker that says "AC Main Disconnect outside." So I go outside with my parts cannon and I notice another box next to my main meter. I open it and it says "AC Main" inside. I pull the fuse holder and ohm them out and they're both blown. So I put 2 new fuses in, and when I engage it into the box I hear sizzling from my right. I walk over and see the condenser fan turning really slowly and smoke pouring out where the wires go into the compressor. It pops out a couple electrical sparky flame balls and I pull the disconnect at that box, then run over and pull the disconnect at the box by the meter. I standby with fire bottle until no more smoke or heat.
so, WTF?!?!
I’m going to guess from your description that the compressor is seized or it’s shorted to ground internally. Something major is typically required to pull the kind of current to make smoke and sparks. If you have a multi meter, disconnect the power and remove the leads from the motor terminals. (Mark them first.) Check for continuity between each of the three terminals and a good ground inside the unit. If you have continuity to ground unfortunately it’s game over for the compressor. If not, inspect the wires for chafing or something else that could cause a short between the leads.
You say the outside fan is only a couple years old. How old is the system, specifically the compressor?
1988RedT2 said:
You say the outside fan is only a couple years old. How old is the system, specifically the compressor?
I've lived here 12 years, and it looked to be 10 years old (?) when we moved in.
AngryCorvair (Forum Supporter) said:
1988RedT2 said:
You say the outside fan is only a couple years old. How old is the system, specifically the compressor?
I've lived here 12 years, and it looked to be 10 years old (?) when we moved in.
My guess would be that the compressor is used up and toast. Unless there is some obvious short externally. While others will chime in with miraculous tales of long-lived compressors, 20 years would be a more than reasonable lifespan.
Unfortunately, sounds like you are headed for a new heat pump at a minimum.
First quote $5800. He said compressor is shorted, and we'd need a complete new outside unit because it's an R22 system and everything is R410 these days. He also said we'd need a new coil inside for the same reason. I was ok until he said "let me check the furnace heat exchanger for cracks, because it's a known issue with this model and vintage." FWIW, Bryant 110k btu natural gas from 1997.
the $5800 did not include furnace heat exchanger.
gonna get a couple more quotes.
Ouch. Probably best to go with a complete new system. I think you can take a tax credit, and there is (hopefully) some benefit to higher efficiency and lower fuel costs.
Plus, you should be good for another 15-20 years.
AngryCorvair (Forum Supporter) said:
First quote $5800. He said compressor is shorted, and we'd need a complete new outside unit because it's an R22 system and everything is R410 these days. He also said we'd need a new coil inside for the same reason. I was ok until he said "let me check the furnace heat exchanger for cracks, because it's a known issue with this model and vintage." FWIW, Bryant 110k btu natural gas from 1997.
the $5800 did not include furnace heat exchanger.
gonna get a couple more quotes.
That's in line with what we just had for pricing on ours, we wound up spending more and replacing the whole air handler inside for a higher efficiency unit. That said, we are in the DC area, so local labor may be a bit more expensive.
We just did the exact same thing, got 17 years from it. Left the furnace, new outside condenser and evap coil was $5100 installed for Trane's off brand model. Same warranty I think. It's temporary, but I'm not living thru a 100 degree summer without AC. Plan is to reuse it in the shop.
Second quote was $5400 for AC and another $3600 for 80%furnace or $4700 for 95%
third quote tomorrow from friend of a friend
In reply to AngryCorvair (Forum Supporter) :
Sorry to hear about the grounded compressor, that was my suspicion.
Check to see if your state has a utility rebate program for high efficiency equipment. If you’re replacing the entire system (condenser/ coil / gas furnace) consider an air source heat pump for the outdoor unit. You may be able to get rebates on both and then have a hybrid system for heat as well as the central AC.
