The high pressure switch is in the back of the compressor. You need it empty to remove it. If you charged it with cans and a hose from the parts store you may just have air in the system. What are your pressures doing? I don't know exactly what your pressures should be. It not only has to do with the ambient temp but also the locations of the service ports.

 

I did think to purge my hoses of air before I used them (open up one end and flow freon until freon comes out)

I charged it last night it was about 89F outside. this time the pressures looked better 25-40 Low side 150-200 High side. It was also pulling heat out of the cab better as well. I would have put more freon in but I ran out and need to go buy another can.

it's actually the low pressure switch thats kicking off (when the low side hits 24 psi) i think I just need 1/2 can of straight freon and all will be well.
(The system doesn't have enough freon and the pump is sucking the low side below the freezing point and kicking off the compressor. Is my logic correct?)

Also what are the high and low pressure switches rated for? (at what point to they kick on or off?)

Thanks a lot for the help

 

I did think to purge my hoses of air before I used them (open up one end and flow freon until freon comes out)

I charged it last night it was about 89F outside. this time the pressures looked better 25-40 Low side 150-200 High side. It was also pulling heat out of the cab better as well. I would have put more freon in but I ran out and need to go buy another can.

it's actually the low pressure switch thats kicking off (when the low side hits 24 psi) i think I just need 1/2 can of straight freon and all will be well.
(The system doesn't have enough freon and the pump is sucking the low side below the freezing point and kicking off the compressor. Is my logic correct?)

Also what are the high and low pressure switches rated for? (at what point to they kick on or off?)

Thanks a lot for the help

Your switch shouldnt be kicking it off at 24 psi. It ran lower than that with r12. As soon as you give it gas it will suck your pressure down. I would say 200 to 225 is good on your high side and 30 or so on your low side.

 

i believe if you open up the system you have to have it vacuumed (sp?) down.

 

Only if...

The pressure in side the system becomes equal to or lower than atmosphere. There-by sucking in atmosphere (70%nitrogen 25%oxygen 5%other stuff.)

but yes if you open up a system you are supposed to pull a good vacuum on the system before refilling with freon.



But why is my low side switch kicking off at 24 psi. Could it be faulty?
I should be able to put more freon it this Friday and see how well it works


thanks guys!