Hi,

After a recent warm day I turned on my AC but didn't get cold as expected.

I have checked and found the following so far.

Fuse for compressor ok.
Compressor not turning on.
Short out contacts on pressure switch and compressor starts
with compressor running as above air still at ambient with fans on.
Check continuity across pressure switch - open circuit.
Switch continuity does not change after running compressor for 10 mins or so.
Depress plunger on a/c gas valves under dust caps - very little pressure so suspect no Gas.

Will get gas recharged on Monday but....pressure switch...
I would expect it to be closed circuit when pressure low or compressor would never run. Do they go bad? Are they adjusable? I note a screw between the contacts recessed within the switch socket.

Thoughts please.

Simon

 

Yeah they do go bad, mine actually just went out and I got it replaced, I had a shop test it to see what was wrong with the AC system and they bridged the connection at the low pressure switch and it fired up!

 

is it possible to change the switch without loosing the gas? I assume the sensor is open to the gas pipe so removing it will let whats left escape.

 

If you don't have a good freon charge, the compressor will not come on either. That happened to me a couple Summers ago.

Good luck,

 

I've arranged for a AC guy to come have a look with it and spoken to my mates in GA who are in the AC business and they have confirmed to check the gas before changing the switch. Also apparently the orifice tube is prone to getting gummed up too - a $6 part. I but they cost a hell of a lot more over here!

Will let you know the outcome.

 

i do believe the switch can be changed without losing the freon charge.and if you are low on freon the compressor will not run.