Strange event draining air compressor

[f575gtc]

As some of you may know I came across a older Sanborn Industrial air compressor last month for $200, I finally got around to wiring it up with a new magnetic starter and ran it through its first 0-full cycle under my ownership.

Now my air compressor is in my garage, where it never drops under 50 degrees unless the doors are open. Today I let the compressor fill up and let it sit for about an hour, came back, saw it was holding pressure nicely, so I decided to let the air out the bottom.

I have a 1/4 inch ball valve acting as a drain. Now here is where things got weird, I opened the valve and the air started rushing out and within 30 seconds it started sputtering, I checked the valve and noticed the thing had frozen itself shut... The valve had a nice chunk of ice in it preventing the air from draining out...

Has anyone ever had this happen? its extremely odd as my garage was not cold, and there was no way the air could have been under 32 degrees.

Also on a side note, the cut off on the pressure switch is very low, it is only 120psi max, the tank is rated for 155 and the pump for 145 so I wanted to crank the cut off to 140 and the cut in to 110, the switch is a square D, does one tighten the cut off nut clock wise to increase the cut off pressure? or is it counter clockwise?

 

[Charles (in GA)]

When you rapidly reduce the pressure of air, it cools dramatically. Thats how a cold gun works. Thats why air tools get cold when you use them.

Charles

 

[EOC_Jason]

The air is going from high pressure to low pressure, same principle as how an air conditioner works. If the temp was close to freezing and you had a fair amount of water in the tank...

Also noteworthy is: http://en.wikipedia.org/wiki/Venturi_effect

 

[Heavy tech]

It's not that uncommon for valve stems on semi truck wheels to freeze up when draining the air from them in the middle of summer. Actually, it seems to happen more in hot weather. Maybe someone smarter than me will chime in as to why it happens.

As for the pressure switch, yes . Turning the nut clockwise should increase cut out spring pressure thus requiring more air pressure to over come the spring pressure and cut out the compressor.


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[larry_g]

I for one would not recommend that you up the pressure cutout. Your dealing with an old pump that on its best day would only do ~150psi. Now with some wear your going to be pushing things. What I would suggest you do is time the fill time from cutin to cutout before you do any adjusting. Then time things at the new settings. You will find that the compressor is working quite hard to put that last 10 lbs into the tank. I'm also assuming that you are dealing with a single stage compressor here. If it is a two stage then ignore the above.

lg
no neat sig line

 

[f575gtc]

It just caught me off guard. Now that I think about it, when pumping air, my old compressor's tank did get very hot.

 

[volleyball]

Now we know how the A/C works.
The warmer the air, the more moisture it can hold.

 

[Jarhead0408]

Uhh, Dude, I hope you didn't put your eye level with the drain hole? If that chunk blew out it would relieve you of an eyeball!!!!!

 

[f575gtc]

lol, would I win the Darwin of the year award then?


it had enough ice build up sticking out of the valve to see it, I then closed the valve and stuck my tongue on it to determine its composition.

 

[90zcar]

My showcar is on air ride and when I drain the tank in that in the middle of the summer it freezes. I also run 200psi in the tank so it really is pressurized...


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[b-body-bob]

it had enough ice build up sticking out of the valve to see it, I then closed the valve and stuck my tongue on it to determine its composition.

It's a good thing you're typing and not talking or we wouldn't be able to understand you. BTW, if you get tired of waiting you can contact the fire dept, I hear they know how to unstick a tongue from a flagpole, they should be able to do the same for you.