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A/C compressor

Don't know much about A/C since I live in a temperate clime, but g.f. lives in a hot place. Tenant in her rental house said the A/C wasn't working. Tech went out and replaced the starting cap for $120. Unit worked one day and stopped. Tech says the compressor "shorted out." Cost for a new one is $800 installed.

Temp there now is 105 so don't have a lot of time to kill doing research, but would appreciate feedback.

  1. Do compressors "short out" or is that just a mis-used term for "stopped working for some reason?"

  1. What is the likelihood that the tech screwed something up while replacing the cap?

  2. Is it likely that there's a compressor fault that can be fixed without replacing it?

  1. Are the compressor motor and pump separable?

  2. Are used compressors available? Rebuilt?

  1. Why did the unit run for 24 hours with a new starting cap if the compressor is faulty?

  2. Any other questions for the tech or suggestions for the g.f. appreciated.

Absolutely no interest in spending any more than absolutely necessary to make this thing limp along for a few months, as the house is going up for short sale within a few weeks.

Reply to
Smitty Two
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Comments are under questions.

Could be either, but normally the term means that some of the wiring in the compressor is really shorted. Either to each other or to ground.

Probabaly not.

Not if it really is shorted or other wise bad.

They are usually a sealed unit containing both in home units.

I do not know about this in your area.

It could have been a few shorted turns in the windings and then enough shorted to make it quit.

Reply to
Ralph Mowery

ONE HUNDRED AND TWENTY DOLLARS for a five dollar capacitor? Anyway, my uninformed answers to your questions:

#1 "Short out" - I guess it could happen, but I never heard of that nor know how one would test for it. #2 "Tech screwed up" - Possible. I'm not sure how. #3 "Compressor fixed?" - Again, possible. Depending on what's wrong. You can't really FIX a compressor, the whole thing is sealed, but the problem could be elsewhere in a place that CAN be fixed. #4 "Compressor and 'pump' separate?" - No. It's one sealed unit. #5 "Rebuilt units available?" - Never heard of one #6 "Why did it run for a day?" - I don't know. #7 "Additional questions" - Why are you using this tech?

I think it's POSSIBLE that a defective cap put such a load on the relay that it burnt the points. The capacitor and the relay are about the only serviceable parts IN a compressor unit.

Reply to
HeyBub

For a tech to come over, daignose it and replace a cap, that sounds like a reasonable charge.

It happens. Just like it can happen on any other motor. Insulation on the windings fail and eventually short, producing more heat, more failure, until it's cooked and kaput.

Probably not. It could have been it was starting to fail and having difficulty starting and he concluded it was just the starting cap, but it turned out to be much worse.

It's a sealed unit and if the compressor is shot, no fixing it.

When getting this fixed, another consideration is that the failed compressor could have sent burned crap through the rest of it. That has to be carefully evaluated and flushed out if necessary or else you could wind up with more problems down the road.

Meaning it's a good time to consider other alternatives, like replacing the whole AC sytem, ie entire condenser and evaporator. Depending on the age, efficiency of the old one, rebates from electric company, etc, that could be a more logical choice. Perhaps for not a lot more you could wind up with a whole new system.

Years ago I had the compressor fail on a system I had that was only about 7 years old. I elected to just replace the compressor because of the age of the system and I had a guy who could do it for only $600 at the time.

Reply to
trader4

Likewise. Mine went blooey after Hurricane Yikes. My son's neighbor, a Guatemalan, moonlights in the repair business. He contacted one of his expatriate contrymen who makes a market in used equipment. I got a two-year old condensing unit (Rudd) installed for $700... at eight o'clock at night.

Reply to
HeyBub

That's pretty reasonable. You don't mention the tonnage but even a couple tons is probably $6-700 for the outside unit at his prices. It's been my experience that you can double the equipment price to get a good idea what it will be installed. The 5 year warranty will help with the sale.

Reply to
jamesgangnc

A base of $100 for a service call does not seem out of line given the time, travel, fuel, overhead, etc. $20 to replace a cap doesn't seem excessive either.

Reply to
Pete C.

There are many service people that do not have a good idea of how to repair anything. The just throw parts at it and finally hit on the part that fixes it.

If the service man does not know the differance between an open and a short, I think I would look elsewhere. The refrigeration part is simple, it is the contrlos in the newer units that are complicated. If it is an old system, most anyone can get it going.

I work as an electrician/instrument technician in a large company. There are about 25 in the shop. Out of them , there are about 3 that are very good, 5 more that can do a fair job and the others just change out parts and hope they find the correct one.

A few years ago my heat pump would not go into a defrost cycle in the winter. The repair man came out while I was at work. He replaced the fan and capacitor for about $ 350. I did not think it was the fan as it was running but there was ice on the outside unit. Called him back and he said something about the electronic board and left. Said he would be back when he found one. I called him when I got home and told him to just forget it. AS the unit was about 15 years old, I went with another company and had a new unit installed. I know that is not a good option for a house on a short sell.

Reply to
Ralph Mowery

For what it's worth the fan should not run while the unit is in defrost. That is controlled by a relay on the defrost control board. I have had a case where a short in the dual run cap shared by the fan and compressor caused the fan to continue to get power even though the defrost control board had turned it off. But in most cases the fan relay on the defrost control board is bad if the unit switches to cool mode but doesn't turn the fan off when forced into defrost mode.

The defrost control board simply switches the unit back to cool mode and shuts off the fan. Heat from inside the house is used to defrost the outside coils. How the defrost control board decides to do that varys. Some are simple timers. Others have various temp sensors that detect when the outside coils have started to freeze.

Reply to
jamesgangnc

Well, you're right of course. But that's why so many hang out here to learn how to do things on our own.

In the instant case:

Ten minutes to remove capacitor Thirty minutes to meander to Grainger's for a replacement (~$10) Ten minutes to install and try the new cap

So the gamble is an hour of my time, plus ten bucks, vs $100. (Already have the capacitor)

Reply to
HeyBub

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