Air Pressure Switch

[dale farley]

I need to change the air pressure switch on my auxiliary air system. When the aux compressor pumps up and shuts off it is supposed to exhaust via the unloader valve at the top of the blue air line. The small "L" shaped arm (top right of first picture) pushes the small pin down when the max air pressure is reached. Mine goes down and never comes back up so it continues to exhaust air until it leaks down and the compressor comes back on.

I ordered a new pressure switch, thinking it would "be like mine. Unfortunately it does not have the "L" shaped arm or the hole to mount the unloader valve. The old and new pressure switches appear to be the same except for the "L"shaped arm. Does anyone know where I can find a regulator that has the "L" shaped arm built on it? Hopefully, the pictures makes this a little clearer.

[jack14r]

I would try WW Grainger

[Joe Camper]

Dale the compressor from california air has its own limit and regulator.

[JIM KELLER]

Dale, could the replacement switch you purchased be for water ?

[jack14r]

Dale,you need one with an unloaded WWGrainger has several,they also sell the unloader separate for about $10.

[Mikee]

The unloader is supposed to empty the air line so the compressor will not start under a load. There should be a check valve between the compressor and aux air tank. The unloader line is between the air compressor and this check valve. It sounds like the check valve is not working, thus allowing the unloader to drain the aux system.

Mikee

[Joe Camper]

Yes exactly but dale has other related issues IE a juneair aux compressor that is pumping out entirly too much oil.

Save the money on that reg and chuck the juneair for the one I showed u.

[dale farley]

Joe, I ordered the new air compressor and it has been really handy for driving air tools, etc.
while erecting privacy fence in Huntsville. In other words, it hasn't made it to Pensacola. The Jun Aire seems to be working better so I hate to scrap it at this time.

Mike, I did change the check valve, and it made no difference.

Jim, I did purchase one from Lowes that said it was for air compressors. Below is the description, and it looks like the original except for the "L" bracket.




The Square D by Schneider Electric pressure switch for use with air compressors and set to turn off at 100 PSI and features a 1/4-in NPSF pressure...
Suitable for control of small electrically driven air compressors
Off at 100 PSI

[dale farley]

As Jack suggested, I found the pressure switch at Grainger. I had called them earlier, but they said they didn't have it in stock, and I would have to open an account before they would special order it. I went there today, and they had one with the same specs. Got it installed and everything works fine. I did not realize until today that air bleeds out of the pin hole of the unloader while the compressor is running and stops bleeding when the compressor shuts off. I assume this is normal operation.

[Gil_J]

Dale,

The unloader is suppose to bleed off the head pressure on the compressor pump when it turns off. The reason is to reduce start up resistance on the compressor motor. As you describe the unloader's current operation it would seem it is working backwards. Maybe, I' m not reading your post correctly.

[dale farley]

Gil,

The unloader does engage when the compressor shuts off and bleeds there is one blast of air as it should be. While the compressor is running, I hear air coming from the little hole in the unloader. The air ceases as soon as the compressor shuts off and the unloader engages.