Air Conditioning - Help diagnosing central A/C which died yesterday
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RemodelNovice
07-25-06, 04:52 PM
Central A/C unit (Carrier), 12 years old, has never had any issues or service other than routine maintenance. San Diego hit a huge heat wave this weekend and about 4pm on Sunday, I noticed the A/C had gone off. This unit had been running all weekend, but that was fairly normal (we use our A/C a lot). After some initial confusion, I started my investigation.
Initial symptoms:
- Outside unit fan spins normal. No unusual sound or problems.
- Air in house is moving, and controls otherwise act normal.
- I hear a very faint "bzzzz" sound which goes for about 3 seconds, but no compressor sound.
- No cooling at all in the house.
What I did:
- Check and cleaned immediate area; nothing obvious in way of dirt or overgrowth.
- Removed contactor and *thoroughly* disassembled and cleaned.
- Verified that 24V is getting to contactor (via delay circuit) okay, and that contactor is engaging.
- Verified that 230V available at souce of contactor, and after relay engages, that 230V available at output.
- Dropped delay circuit from system with no noticible change or improvement (put it back afterwards).
- No start capacitor or circuit in this model, so didn't check it.
- Wires to compressor in good shape, connectors clean and free.
- Replaced run capacitor with brand new one with no noticible change or improvement.
- Verified that fan+common = 230V (actually, 330V, but appears to be okay).
- Verified that herm+common = 0V normally, and then when that bzzz sound occurs, jumps to 230V for the duration, then returns to 0V.
- Fins all generally in good shape and clean.
- Compressor very hot to touch
I'm at a loss. It *feels* like the compressor is either locked up or dead. I'm out of my league though -- I don't know how to go any further on checking the compressor or cleaning coils, etc.
I'm thinking about buying a kickstart hard start kit and installing it and seeing if it will kick the compressor, but I welcome other advice, suggestions, ideas, or questions. Can anyone help?
I'd be calling an A/C repair guy for this, but they're booked solid and don't have an opening until 14-Aug!! :-(
HELP!!
thanks,
bruce
Initial symptoms:
- Outside unit fan spins normal. No unusual sound or problems.
- Air in house is moving, and controls otherwise act normal.
- I hear a very faint "bzzzz" sound which goes for about 3 seconds, but no compressor sound.
- No cooling at all in the house.
What I did:
- Check and cleaned immediate area; nothing obvious in way of dirt or overgrowth.
- Removed contactor and *thoroughly* disassembled and cleaned.
- Verified that 24V is getting to contactor (via delay circuit) okay, and that contactor is engaging.
- Verified that 230V available at souce of contactor, and after relay engages, that 230V available at output.
- Dropped delay circuit from system with no noticible change or improvement (put it back afterwards).
- No start capacitor or circuit in this model, so didn't check it.
- Wires to compressor in good shape, connectors clean and free.
- Replaced run capacitor with brand new one with no noticible change or improvement.
- Verified that fan+common = 230V (actually, 330V, but appears to be okay).
- Verified that herm+common = 0V normally, and then when that bzzz sound occurs, jumps to 230V for the duration, then returns to 0V.
- Fins all generally in good shape and clean.
- Compressor very hot to touch
I'm at a loss. It *feels* like the compressor is either locked up or dead. I'm out of my league though -- I don't know how to go any further on checking the compressor or cleaning coils, etc.
I'm thinking about buying a kickstart hard start kit and installing it and seeing if it will kick the compressor, but I welcome other advice, suggestions, ideas, or questions. Can anyone help?
I'd be calling an A/C repair guy for this, but they're booked solid and don't have an opening until 14-Aug!! :-(
HELP!!
thanks,
bruce
Jay11J
07-25-06, 04:59 PM
Sounds like the compressor is locked up, and tripping on the internal overload limit.
May have to get a hard start kit and if it can lossen it up. but if that don't do it.. May be due for a new compressor. Turn it off, and don't let it try to start other wise. may burn out.
May have to get a hard start kit and if it can lossen it up. but if that don't do it.. May be due for a new compressor. Turn it off, and don't let it try to start other wise. may burn out.