A/C pressures
Posting Guru
Joined: Nov 2007
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From: West Texas
150 on the high side is pretty low. So is 25 on the low side. More like 30 low and 250 high with around a 90 degree ambient temp. Not over 300 idling. It should never run over 350. Somethings wrong if it does. I think the blow out valve on these is around 375 or 400.
Weighed charges only work right on a completely stock system. If anything has been replaced then you have to go by pressures. Especially if it's the compressor or receiver dryer. The volume difference in an aftermarket dryer and the factory one can be as much as half a pound! That's more than enough to screw the system real good.
If you have to open the system get a van orifice tube in it then charge to a slightly lower high side. Makes the wife freeze every time.
If your compressor isn't cycling while it's idling and the receiver dryer is cold and has condensate running off of it then I wouldn't hook the gauges to it. All it's gonna do is get crap in the system that wasn't necessary. If you have frost on the dryer or it is cycling then go ahead and check it. I always like to pull a vacuum on my gauges before i hook them up.
Weighed charges only work right on a completely stock system. If anything has been replaced then you have to go by pressures. Especially if it's the compressor or receiver dryer. The volume difference in an aftermarket dryer and the factory one can be as much as half a pound! That's more than enough to screw the system real good.
If you have to open the system get a van orifice tube in it then charge to a slightly lower high side. Makes the wife freeze every time.
If your compressor isn't cycling while it's idling and the receiver dryer is cold and has condensate running off of it then I wouldn't hook the gauges to it. All it's gonna do is get crap in the system that wasn't necessary. If you have frost on the dryer or it is cycling then go ahead and check it. I always like to pull a vacuum on my gauges before i hook them up.
Post Fiend
Joined: Apr 2004
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From: Silver Lake Dunes, MI
That is a regional thing. I live in Michigan. We start doing A/C work like crazy the first day it hits 75 degrees. West Texas is a little different. You guys are still doing heater work at 75.....
Posting Guru
Joined: Nov 2007
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From: West Texas
Yeah in the winter here we use the heater in the morning and the ac in the afternoon. Those pressures would be about right for the temp I said though no matter where it is. You shouldn't be seeing that high too often.
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Joined: Sep 2009
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From: Socal desert
Thanks to everyone.
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Deadeye1963
1961 - 1966 F-100 & Larger F-Series Trucks
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Oct 26, 2004 11:23 PM
