20 Years Old Carrier Central Ac Units

by Billy N
(knoxville AR 72847)

My carrier central air conditioning condenser fan and compressor is not kicking on. Some shady local technicians said that it was a problem with a capacitor. They also said they replaced it with a new capacitor.

When i looked in the service box a portable "test" type capacitor fell out and was dangling by the leads the "new" capacitor was not new but WAS different than the one which was previously mounted in the box.

The magnetic contact which i showed them to be burned and malfunctioning was even more burned and pretty much welded in the on position. This switch was what i thought was the problem to begin with. They charged me 200 dollars and were there about 20 minutes .

I had to throw the main breaker because the outside unit would not cycle off due to the melted magnetic switch . These guys repeatedly told me to SAVE my money because the aging yet previously reliable compressor could suffer catastrophic failure at any moment.

Do you think leaving both those capacitors installed and failing to change out the magnetic contact switch was negligence, incompetence or an act of sheer sabotage.

I am very upset with these people no matter what he answer to that question may be. It was 100 degrees yesterday and expected to be even warmer today. The permanent capacitor is an amper N144050R350 and looks to be either 35 amps or 75 amps it is to beat up to read. The model number is carrier 77CA04300. serial number is 0388E14139.

I have some knowledge of the industrial refrigeration field, but am no expert. Any info or advice will be appreciated.

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repairing central a/c NEW
by: Anonymous

Sometimes the contactor goes bad because the compressor cannot run. If your compressor is still able to run, All you need is a contactor.

I'm assuming you are talking a residential unit, so the coil voltage on the contactor is 24 volt.

The contactor will be two pole and you just need one that has a higher amperage rating on the contactor contacts than what is the amperage draw on the unit. This info is found on you nameplate.
Contactor is probably $ 50.00

simple 1hr call NEW
by: Anonymous

tech was terrible. caps blow all the time. inexpensive and easy to diagnose. contactor burnt, another common failure when that old. get parts for under 75.00 and a 1 hr call. my personal a/c is a builders mod. G.E. going on 36yrs old. only furnace upgraded. im a 40yr tech, union member.

20 years&still goin! NEW
by: Anonymous

Our 2 ton condenser was installed in 1992 and technically, still cooling. I put it that way because last fall the outside unit just ran and ran over a 3-day heat wave.Wouldn't shut off and house got to 97 degrees inside.turned out the 35mfd. capacitor was 'shot'Our local,very trustworthy guy replaced it and Even though he said the outside condensing unit should be replaced, it's still cooling this year.ans shutting off okay.we'll replace it next month just cuz it's 20 yrs. old.
And don't want it to quit in a bad august heat wave only then to discover a replacement capacitor won't 'do the trick' any longer. so we've had great luck with our carrier, and it runs a separate in attic blower system. which was a "blast"LOL to install, up through an old 'whole house fan' hole in our hallway. Coulda been worse, with no hole ready-made i guess.

39 Year Old Carrier Central Air Conditioner
by: Judy S

We installed a 36,000 BTU system 39 years ago. About 5 years ago we had to replace the A coil because it sits inside our hot-air furnace and it rusted. We are still using the original outside unit and it runs well.

About 10 years ago we had to spend $90 for a small part. Other than the new A coil and the small part, the Carrier has run without problems all these years. The only maintenance we do is covering the outside unit for winter.

Outdoor Unit Not Running
by: Dadan

Hey, Bill

Not changing the contactor is negligence on your local tech parts. Carrier condenser unit not running could be from bad contactor.

(The permanent capacitor is an amper N144050R350 and looks to be either 35 amps or 75 amps it is to beat up to read.) You mean the run capacitor for the outdoor unit correct? You central ac capacitor would be 35 MFD for compressor and 5 MFD for the condenser fan
(I had to throw the main breaker because the outside unit would not cycle off due to the melted magnetic switch.) If you central ac unit is not turning off and you have to switch the main breaker to turn it off, it could be the contactor is to burn or welding to open the contactor switch. Use you ohmmeter to find if the contractor is close or open.

If you are planning to buy new contactor, it has label on your contactor. So, use that information to get a new contactor.

Electricity is not something to have fun with, if you have doubt call different HVACs Service Company.



I trying looking up the model and serial number for your Carrier central ac unit and it seem my guide does not have the info on your central ac unit.

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