Posted: 7/29/2014 8:54:41 AM EDT
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Yay.
Hottest part of the year and we're blowing hot inside. The breaker tripped a week or so ago after storms. I reset and all appeared well. I checked and it's tripped again, upstairs air handler blowing hot, outside fan and compressor not running. Immediately trips on reset. Swapped breakers, trips on new breaker. Ok. Not an HVAC expert, but fix things for a living, and youtube, right? Pulled three compressor leads. Breaker does not trip. 
Contactor is not engaging, (unsure if it should with compressor disconnected,  ) but when I push the contactor in, fan runs normally without tripping breaker.
Ohmed 3 leads to compressor, all three ohm out low resistance, so no open. Then I took all three to unit housing/ground. All three have continuity to ground. Crap. Shorted compressor seems to be my amateur diagnosis. Any expert advice besides pepper my angus? Should the contactor be engaging the fan regardless? Any chance I missed something that won't be a fiscal MOAB? |
| Compressor is grounded. Depending on age, I would change compressor. If over 5-7 years old consider changing condensor. You can still get dry charged R-22 condensor/heat pumps. Seer rating won't match, since the 13 seers came out I've put several on older indoor coils. Some of them I've added a TXV and all runs well, some run as is. |
| If the inside unit is calling for the cooling/compressor to be on, the contactor should be pulling in via 24 volt coil. If the inside unit is set to cool and the contactor is not pulling in it could be an error stored. Reset both breakers with the compressor unplugged and the contactor should still pull in, if the high head pressure/limit switch, or other safety switches are not open. You are on the right path. |
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10 YO CARRIER unit, should have mentioned.
Will try resetting trick to test contactor. I will have to check on replacement condenser costs vs new unit. Did I mention I'm not much of an HVAC guy? 
I'm willing to screw around within my suspected limits, however, so long as life, limb, and financial ruin aren't at risk. Be back shortly, if not...... |
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Sending wires look ok, wire nut connections tight, contactor still not auto engaging, but fan runs when it's pushed in.
Compressor has a short to housing. Trying to figure out how to look online for a replacement compressor, or whole new outdoor unit. Model numbers on housing and compressor not helping much. What specs do I use for comparison? Unit Model: 38YCC024340 Unit SN: 0605E30186 Compressor Model: H29B24UABCA SN: 02806088671 |
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Sending wires look ok, wire nut connections tight, contactor still not auto engaging, but fan runs when it's pushed in. Compressor has a short to housing. Trying to figure out how to look online for a replacement compressor, or whole new outdoor unit. Model numbers on housing and compressor not helping much. What specs do I use for comparison? Unit Model: 38YCC024340 Unit SN: 0605E30186 Compressor Model: H29B24UABCA SN: 02806088671 Did you check the start capacitor on the condensor? Extremely cheap to replace, just a few bucks. |
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Did you check the start capacitor on the condensor? Extremely cheap to replace, just a few bucks. Quoted:
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Sending wires look ok, wire nut connections tight, contactor still not auto engaging, but fan runs when it's pushed in. Compressor has a short to housing. Trying to figure out how to look online for a replacement compressor, or whole new outdoor unit. Model numbers on housing and compressor not helping much. What specs do I use for comparison? Unit Model: 38YCC024340 Unit SN: 0605E30186 Compressor Model: H29B24UABCA SN: 02806088671 Did you check the start capacitor on the condensor? Extremely cheap to replace, just a few bucks. Yessir. I had a spare on hand and it was the first thing I checked. |
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Ok, seems compressor is shorted.
Crap. So what's fair BALLPARK for a replacement R22 Compressor, parts/labor? Entire 2 ton condenser unit? Total changeout to newer air handler and condenser? I "know a guy" who's saying 800-1500 for a compressor changeout, 2-3K for an R22 Condensor unit changeout, and 3-4K for an air handler/condenser changeout. Seem reasonable? |
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Quoted: Ok, seems compressor is shorted. Crap. So what's fair BALLPARK for a replacement R22 Compressor, parts/labor? Entire 2 ton condenser unit? Total changeout to newer air handler and condenser? I "know a guy" who's saying 800-1500 for a compressor changeout, 2-3K for an R22 Condensor unit changeout, and 3-4K for an air handler/condenser changeout. Seem reasonable? |
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I do like these threads for the learning opportunity but I do have a hard time understanding what testing the OP is doing. I may have to google youtube to understand how he tested things and came to his failure diagnosis. Neither compressor nor fan runs, breaker tripped. Breaker to outside condenser unit trips immediately on reset. Blower, on separate breaker runs, blowing hot. Changed out run cap as I had a spare on hand, and it was easy. No effect. Swapped breaker on off chance of bad breaker, new breaker trips too. Disconnected compressor (three wires) in outside unit, breaker stays on, proving no short /overcurrent wiring fault to point on contactor/cap Compressor is hooked up to. Manually pushed contactor closed with power applied, fan motor comes on and runs normally, no short in fan motor, unsure why contactor won't auto close, maybe bad contactor or undiscovered signal wiring flaw? Measured resistance between each of three disconnected compressor wires to check for an open (not likely, due to short indication), no open. My understanding is there should NOT be continuity between each of three disconnected wires and unit ground/frame, there is, on all three. As I understand it, this demonstrates compressor has an internal short to ground, tripping the breaker. |
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Those prices seem reasonable. That's pretty much what I charge to do it, if I'm using carrier or Trane. If he's using Ruud or the like it should be a little cheaper. Quoted:
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Ok, seems compressor is shorted. Crap. So what's fair BALLPARK for a replacement R22 Compressor, parts/labor? Entire 2 ton condenser unit? Total changeout to newer air handler and condenser? I "know a guy" who's saying 800-1500 for a compressor changeout, 2-3K for an R22 Condensor unit changeout, and 3-4K for an air handler/condenser changeout. Seem reasonable? Thanks. That's what I was afraid of. Appreciate all the feedback guys, this site is well worth the $24 yearly investment. |