michcumm

I replaced my a/c compressor recently (the clutch on the old one was going so i jus replaced the whole compressor, also the air worked great before I took the old compressor off) I recharged the system, (I first pulled a vaccum), then put 3 or 4 12 oz cans in to try and get the low side pressure higher. The compressor wont engage unless I bypass the low pressure sensor. High side psi is 175, and low is 25. With a paperclip in the low pressure sensor it blows ice cold air. Does anyone know the specs on the low pressure switch like what minimum psi it needs?

clutch1

is the compressor cycling on and off without using a jumper wire and low psi switch hooked up, or does it not come on at all.

michcumm

It wont cycle at all without the jumper wire

clutch1

more than likely the switch is bad should at leats cycle at 15psi. what do you have going to the switch as far as voltage.

michcumm

Not sure I'll check tonight

wv smoker

Pressure reading sound kind of low to keep the switch open to me. I rarely use gauges to re-charge, I just keep putting gas in till the low side starts icing up. Your gauge reading sounds kind of odd, usually the high side is near double the low side? Seems to me that if it was working OK before it should work now unless it is freezing up? Probably should have replaced the dryer too, but if you didn,t have the system open very long it may be OK. You puttin in R 12 or 134? If you have to use a gauge, I would make sure they are calibrated fairly close and don't let the high side go over 300 depending on the outside temperature........WV Smoker........

clutch1

high side seems low but not sure what his ambient is.

michcumm

The volts to the low psi switch are 14. The ambient Temp is about 70 degrees with little or no humidity. Used R134 refrigerant

clutch1

change your switch and be done with it.

clutch1

with that ambient you are a little low 70 degrees high side should be around 200 +-20 so 180 to 220 depending on condition of system, also 15 to 40 good low side

michcumm

Thanks for the input, Ill pick up a new switch tomorrow.