A/C stopped working after recharging

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M1Accord

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Well, this falls into another "It wasn't broken but I fixed it and now it's broken" category. My Corolla had working A/C but I thought the cold air wasn't cold enough so I recharged it without knowing how much to put. Chances are I put too much freon in it and now it stopped working. I can tell the engine goes into load when I put A/C on but no cold air coming out. What should I do and what tools should I get to fix this? I put the gauge that came with the charger and the needle goes into the section reading A/C not functioning correctly. Could overcharging the system damaged it? What are my options?

Thanks.
 
Originally Posted By: M1Accord
Well, this falls into another "It wasn't broken but I fixed it and now it's broken" category. My Corolla had working A/C but I thought the cold air wasn't cold enough so I recharged it without knowing how much to put. Chances are I put too much freon in it and now it stopped working. I can tell the engine goes into load when I put A/C on but no cold air coming out. What should I do and what tools should I get to fix this? I put the gauge that came with the charger and the needle goes into the section reading A/C not functioning correctly. Could overcharging the system damaged it? What are my options?

Thanks.


Probably didn't damage it. Most AC systems have a pressure overload safety - too much pressure and it won't function. You buy cheap....... you get cheap. Take it to an AC shop that has a real set of gauges - not the toy that comes with DIY can - a recovery system, a leak tester, and the experience to do it right.
 
Its more than pressure thats involved. A good shop will remove the freon, check for leaks and put back the proper amount of freon (by weight). R134A is less forgiving than R12.
 
That's a reason why I wait until the weather is hot to charge an AC system, and use either good gauges, or weigh the charge if I'm starting from scratch. You probably over charged the system, I'd have a pro do it now, and not run the AC until you get it fixed. JMO
 
Overcharging will reduce cooling efficiency even if everything else works properly.

I'm pretty sure that at least the older ones had a thermal limiter on the back of compressor. This is a sort of a fuse used instead of an overpressure blowoff valve as a final failsafe but without the whole "venting refrigerant into the atmosphere" feature. The idea is that if head temperature rises too high, the thermal limiter/fuse blows breaking ground to the electric clutch. If you have 12V+ at the clutch but it won't engage, check the thermal limiter.

If the thermal limiter is blown:
Recover all your refrigerant. Disconnect the line at the compressor and at the expansion valve. Verify that you can blow air through the line freely as with no blockage. Verify that the condenser fan works. If there was no overcharge and no blockage and the fan works, replace the expansion valve. Install a new thermal limiter, do not jumper wire across it unless you want to risk the compressor turning into a fragmentation bomb. Reconnect the lines and vacuum down to remove the air and moisture you just added to the system. Charge it up and verify that it works.
 
He said the engine goes into load when the AC is on. I suspect it is considerably overcharged. The best way out of the self imposed mess is to let an AC shop and let them reset the pressure.
 
Why has not anybody advised him to let some freon off via schrader valve? Or he has already tried that but did not tell us?
 
Bleed some refrigerant out of the low side schrader valve, wear gloves and go slow. If the system begins working again you know you're on the right track and can procede accordingly.
As mentioned, it helps if the weather is warm for a/c work as more accurate vent temp readings are possible.

A set of inexpensive gauges, a thermometer to measure vent temps and a little know how can go a long way in dyi a/c work.

Ebay has tons of a/c gauges, well worth the small investment.
 
Originally Posted By: Vikas
Why has not anybody advised him to let some freon off via schrader valve? Or he has already tried that but did not tell us?


I'm pretty sure that would be completely illegal and arguably somewhat irresponsible. It might well work, but advising someone to do that is ethically questionable.
 
Originally Posted By: yonyon
Originally Posted By: Vikas
Why has not anybody advised him to let some freon off via schrader valve? Or he has already tried that but did not tell us?


I'm pretty sure that would be completely illegal and arguably somewhat irresponsible. It might well work, but advising someone to do that is ethically questionable.

R134a is perfectly safe to release, it does not contribute to so called ozone depletion nor global warming.
 
I don't claim to know for sure what harm R134a actually can or can't do, but I'm pretty sure that the federal clean air act prohibits venting it under section 609.
 
In any case, you thought it was weak, added refrigerant, and it became weaker. If you practice "sunshine recovery" you'll be back to a weak system. It might be a weak expansion valve, but would need professional diagnosis. Might as well cut to the chase and take it in. They'll weigh in the correct charge and troubleshoot it from there.
 
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