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Charging the AC system on a C6 Corvette the traditional way has an oddity.
With the conventional gauges and the temperature/pressure tables in hand, we set out to add R134a to replace that which was vented overboard because he had to replace his radiator.
I learned this the hard way once too.
The oddity is you attach the gauges, add some freon R134a then fire up the car with the AC set to its lowest setting with the windows down and the blower running full tilt.
Just about when the low pressure side is nearing the desired range, the high side starts heading for the stratosphere. Often rising far enough that the high-side pressure cut-off kicks in.
"That's odd," we always say.
Shut off the car, let it cool down a bit, restart and check the pressures and they've fallen off a lot.
Add more R134a as normal and both pressures climb right up where they belong and cold air blasts from the vents.
We've come to call it "burping" the system.
My car did it, my buddy's car has done it and we're starting to think it's normal if you're not using the very expensive automatic AC charging cart the dealer will have.
Is thing,la? You're SUPPOSED to reclaim your refrigerant for recycling using a vacuum pump, then refill the refrigerant loop with nitrogen, isolate the fault, repair it, pump it down again (vacuum pump), refill with nitrogen, double check your repair at pressure, suck it down again, and then add new refrigerant. Which is why I no longer work on refrigerant loops on HVAC
ReplyDeleteWhen someone gives me the $5,000 RRR machine, I will start doing all that.
DeleteMost of the time when someone notices their AC doesn't work most of the refrigerant has already leaked out. What usually happens is they get a can or two of R134a with the dye in it and a set of those little chintzy hoses and they fill with that until it starts working, then run the system a while and check with a UV light to see where the leak is. Then they repair the leak and then fill it to full. Is that how it is supposed to be done? Probably not. But it is the reality of how it happens more often than not for people who can't afford to take their cars to high priced shops...
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