A/C compressor stopped running

[muzician21]

Have a Trane central system installed in 88. Model T V030 A140A0 About a year ago the compressor stopped compressing. I replaced the old compressor capacitor and it ran fine until at some point today. This morning it was fine, now it's now. Fan is running, compressor isn't. Contact switch is working. Light on the circuit board is lighting.

I noticed the compressor unit is very hot to the touch. Takes it some time to get cool after shutting it off. Is that what you'd expect from a compressor that had been running?

Any way for me to tell on a DIY basis if the compressor is fried? The cap is only a year old, I'm guessing it's a low level likelihood that it's gone bad again? The old one had obvious "puking" from the seam at the top. No such visible signs on this one.

Thanks.

[.p.jm.]

No.

[Steve]

Its 23 years old... they don't last forever.

FWIW, a new system will cut your heating and cooling bills 30 - 50%

[muzician21]

Hasn't been a big issue - the highest bill I've ever had was about $130. Not bad considering it's around $60 - 70 in a month when the A/C unit is never fired up.

[jamesgangnc]

It is normal for them to be pretty hot when running.

Does it even attempt to start when the contactor is closed? Normally you can hear the compressor trying to start. If you are not certain disconnect the fan, that will make it easier to hear. The simplest test for a bad capacitor is to try another one. The troubleshooting you can do is limited without the various test gear that a pro will have.

Do you think the system was evacuated properly when the compressor was replaced? In some cases when a compressor goes bad it leavs a lot of residue in the refrigerant lines and coils. That's bad for the new compressor. Frankly I'm surprised that anyone recommended replacing a compressor on a system that old. It's past it's life expectancy and replacing the compressor is an expensive job.

[trader4]

Did I miss something? I didn't see him saying the compressor was replaced, only that he replaced the cap last year. Like you said, unless it's the cap, it's time for a service call. And like someone else posted, if it's the compressor, time for a new system. There are frequently tax credits and/or utility rebates for new systems that meet certain standards, depending on where he lives that can help. I would not put more than a couple hundred into a system that old.

[jamesgangnc]

My bad.

[Gz]

I don't notice any difference in cost in the summer on mine. I do have a small house, but I know it's pretty efficient.it's only drawing about 1800 watts. 5 years old.

Greg

[muzician21]

It was the cap. Though it was a little more than a year old it tested weak and was bulging a bit. $10 for another cap, back in business.

[ilbebauck]

It sounds like a possible stalled condition where the rotor of the compressor motor wont turn ; that would cause the compressor to be very hot after awhile. You could try a hard start kit but I dont feel comfortable telling you how to install it as you could get hurt badly . Call a Tech .

[muzician21]

Actually part of me is half-tempted to call out a tech with the bad cap in place and see if he makes an honest assessment or gives me a load of crap but I'm too leery of someone deliberately damaging the unit to sell me on a new one. Too many horror stories about that kind of thing happening. Of course, if they did give it to me straight I'd know they were an honest company I could go to if ever need be.

But it does raise a question - do you know of any dysfunctionality with the a/c system that could cause a cap to go bad prematurely or is it likely just manuf defect? The guy at the parts house said current fluctuations can be hard on caps and Florida is famous for this. It was his assertion that once upon a time similar value caps were much larger and more bulletproof. The original factory cap lasted over 20 years, though unknown how long it had been in diminished condition - apparently they'll continue to work up to a certain threshold? The brand on this one is BestTech. Is there a brand you prefer?

[Steve]

Actually part of me is half-tempted to call out a tech with the bad cap in place and see if he makes an honest assessment or gives me a load of crap but I'm too leery of someone deliberately damaging the unit to sell me on a new one. Too many horror stories about that kind of thing happening. Of course, if they did give it to me straight I'd know they were an honest company I could go to if ever need be.

But it does raise a question - do you know of any dysfunctionality with the a/c system that could cause a cap to go bad prematurely or is it likely just manuf defect? The guy at the parts house said current fluctuations can be hard on caps and Florida is famous for this. It was his assertion that once upon a time similar value caps were much larger and more bulletproof. The original factory cap lasted over 20 years, though unknown how long it had been in diminished condition - apparently they'll continue to work up to a certain threshold? The brand on this one is BestTech. Is there a brand you prefer?

I prefer one that is rated for 440v and is *NOT* made in China. The ones from Pakistan I have used have all worked well with *maybe* a 1% failure rate after 5 - 8 years. The cheap ones from China are junk.

[.p.jm.]

Yeh, but they have a nasty habit of telling the unit next door you're coming.

[Steve]

Nahhhh ...... I was just breathing hard ;-)

[PaxPerPoten]

What happens if he decides that something else caused that Capacitor to fail? That is a Possibility. You did indicate that Capacitor was only a year old with just average usage.

[PaxPerPoten]

Don'tcha just love those plastic Mexican ones that crash and burn tossing hot oil all over and some even start a real fire.

[Daniel who wants to know]

Not a good idea, every time the comp fails to start and trips the overload/overheat thermal cutout it causes some damage to the windings and the cutout itself. Sometimes after repeated use the cutout will weld the contacts instead of tripping and turn your comp windings into crispy critters, after all the cutout is designed to only trip once or twice a year due to things like power blinks that stall the comp and make it try to restart against full head pressure.

Could be a defect but low line voltage takes out run caps sometimes. My aunt put in a small windowshaker and plugged it in to a cheap 16awg extension cord, it didn't last 30 minutes before the cap shorted.

True, actually I would clean and retorque and reseat every electrical connection going all the way back to the main service panel (including the disconnect pullout blades) as bad connections can cause this too.

Me too, 440 over 370 any day of the week.

[Daniel who wants to know]

Forgot to mention, if the condenser coil hasn't been cleaned lately do that too, anything that puts extra load on the comp and slows it down like low voltage or high head pressure puts more stress on the run cap too.