My current vent temp = 72 - 80 degrees. Low side pressure = 55 psi @ idle, high side pressure = 160 psi @ idle.

I pulled a vacuum to -29 psi and checked for leaks. Everything checked out ok. Filled the system with 4 cans of refrigerant. No bubbles in the site glass.

I have cleaned the condenser, and added an electric aux fan in behind the grill.

What should I check next?

Thanks

Charles Alspaugh

There is a good BB here:

http://www.aircondition.com/

Charles First thing and sometimes it gets overlooked check your belt for wear, and make sure its not loose. Did you change the reciever dryer, sometimes the desiccant in the dryer can brake loose and get in the system, causing the expansion valve to act screwy.If your low side line from the evaporator is not sweating I would check the expansion valve close. I have never taken a valve loose on a Volvo, but have taken many loose on other refrigerated equipment,and the inlet side has a screen that you can clean.These conditions can be present if you have a compressor with bad valves also.You may get some more advice by telling the events that led to you having to recharge the system. Good Luck Royce

I would have a look at your heater control valve-- it may not be closing completely, allowing heat into your HVAC system. I can't offer much wisdom on the actual AC diagnosis...

Good luck!

Oh my God! Your low side is WAY high!

I mean, WAAAAAAAY high. You'll never get any cooling at all with that reading.

You should have 38oz in your system. You have 48oz. Get rid of some gaz.

And if you're using 134, you should have 80-90% of THAT figure.

I am using r12. The sticker on the car calls for 2.9 lbs of freon. I was told 16oz of freon = 1 lb. 2.9 * 16 = 46.4 / 12 = 3.87 cans. I tested the A/C with only 3 cans (36oz) and still didn't have what I consider acceptable readings on the gauges or the vent temp. That is why I put the 4th can in.

Any other thoughts on this issue?

Charles

Hm... I might be wrong on the amount (I swore that's what it was), but whatever. Let's assume it has the proper charge--and it would be within an oz. or two.

Something is causing you to have piss poor low side readings. I wonder if the expansion valve is crapped out. Try giving the exp valve a tap with a wrench handle or something when the system is up, and watch the low side pressure if you have that available.

Feel the low side hose and see if it's really warm. I would expect it is, because of the high pressure on the low side.

Get into the console and feel the outlet at the expansion valve. Cold? If so, I'd wonder about the heater control valve. If you are getting ice cold temps at the expansion valve, then you have a problem that most likely exists AFTER the expansion valve, or outside of the a/c system.

That's still curious because you are getting pressure on the high side. But whatever.

The comp. seems to be working... check the other things.