Trying to get my AC working

[shadquattro]

the main function of the lp switch is to protect the compressor in case of leaks its other function is to stop the evaporator freezing up ,short term by passing it would be ok providing that you didnt run the system if it was obviously not working as running it with low pressure or a leak could cause damage to the compressor if it was run with low pressure causing the oil to leak and run the compressor with no oil.
it sounds as if the lp switch is faulty but would only be able to tell if system fully charged

[s2avant]

Bypassing it would allow the compressor to run whether there was gas in the system or not. Running it without gas would wear the compressor out pretty quickly I would imagine.

The switch is not expensive though. Depending on the gas you are using (and your chassis number) you'll need either:

For R12 gas (upto 8B-P-002500 approx)

Switch 893 959 483 B £25.80 + VAT
Seal 431 260 749 A £0.90 + VAT

For R134A gas (8B-P-002501 on approx)

Switch 8A0 959 483 AA £22.37 + VAT
Seal 8A0 260 749 AK this part number supercedes but I can't check it till I'm at work.

Ben

[audiman]

My advise would be not to run it until the correct amount of gas is in the system. Also did you fill the compressor with the correct quantity of oil?? This is very important. Also if its an ABY comp. that was R134a which uses a different type of oil to the old R12 stuff. They dont mix. What gas have you put in there? My R12 comp. holds 295ml of oil. Not sure about the later ones, but that should be fine.