A/C is not real cold
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Joined: Sep 2002
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From: Columbus OH
A/C is not real cold
Just replaced the evaporator, orfice, A/C pump.(new), Dryer, condenser. ony thing left is the hoses. everything works but the low presure is at 50 lbs. and high is 250 lbs. but still only gets slighly cool. anybody have any ideas?
Barry
Barry
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From: Fort Knox, KY
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Re: A/C is not real cold (bwalker1947)
Is the system OVERcharged? Are you running R-12 or 134a? :confused:
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Joined: Aug 2003
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From: Wilmington DE
Re: A/C is not real cold (bwalker1947)
Sounds somewhat overcharged, Did you evacuate the system before charging and measure how much to put in? Also, you need air through the condenser for the a/c to work. Is it still only slightly cool driving down the street? Both fans running while sitting still? Also, are the heater doors closing all the way under the dash?
Just a few for thought.
Just a few for thought.
Le Mans Master
Joined: Dec 2000
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From: San Diego, Ca
Re: A/C is not real cold (bwalker1947)
It's not going to be cold at 50 psi on the low. At that pressure, liquid R12 is boiling at about 55 degrees as it passes through the evaporator. You want 28 to 32 psi with an outside temp of 70 to 90 degrees. At these pressures, the refigerant will be absorbing heat right at freezing. Make sure you're taking the pressure readings at 2000 rpms, main radiator fan on (disconnect the fan switch) and with the a/c on max. Reduce charge until you get it to the 28 to 32 psi range on the low and the high in the range of 2.2 to 2.5 times the air temp at the condensor and if everything else is right, your hands will numb in front of the vents.
Le Mans Master
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Re: A/C is not real cold (scorp508)
About 80% of the R12 fill or a little less than 2 & 1/2 12 oz cans. Charge to pressure though. R134 freezes a little lower so you want it coming out of the low side at about 23 to 25 psi when it's 70 degrees out - it may be 1 or 2 psi higher if its warmer. You also need to turn the screw between the terminals of the low pressure switch counterclockwise 1/4 to 1/2 lowering the cutoff threshold to 22 psi. Check it by pulling the blower harness with a/c on max. Reduced air flow should allow pressure to drop to the threshold causing the compressor to cycle. Do your fill and pressure monitoring at 2000 rpms; otherwise, pressures will be higher and difficult to interpret.
