Compressor Question

[MikeA57]

I have a Campbell Hausfeld 4 hp horizontal 25 gal compressor that I'm wondering if it is running right. Something tells me it isn't but I don't know for sure. I plug it in and the tank fills up, then when it gets to the point at which it's set to turn off it does but air blows out of it until it reaches a predetermined level then it cranks back up again. It cycles like this constantly. I thought that once the tank gets to a certain PSI it would just shut off then once the air is used down to a certain PSI it would turn back on and compress again. Am I wrong in that assumption or should it blow out all the air? I have a single knob which I thought would control how much pressure the tank fills to till it cycles off but turning that doesn't seem to make any difference.

Thanks,

Mike

 

[Mace Canute]

Fix the air blowing out of it problem...

 

[KTurner]

The compressor should fill up, stop, let you use the air, then turn back on when it gets below a certain level. If you're saying that air is escaping all the time, that's a problem that needs to be fixed.

The tank should have a drain valve on the bottom for letting out the water that accumulates. It may be as simple as that being open, letting air out.

Keith

 

[MikeA57]

No, the air is coming from the check or emergency popoff valve that is up near the controls. Sorry, should have included that. Can that be replaced, is it just a bad seal, bad valve or what?

 

[Bird]

No, the air is coming from the check or emergency popoff valve that is up near the controls. Sorry, should have included that. Can that be replaced, is it just a bad seal, bad valve or what?

Yes, it can be replaced. The only time I had that happen, I took it apart, and if I remember right, the seal was like a piece of leather and I simply turned it around and put it back together.

Turning the knob is probably the pressure regulator and it regulates the pressure of the air flowing out of the tank; has nothing to do with the amount of air pressure in the tank or the pressure that cuts off the motor.

 

[Egon]

Mine does the same thing on a very sporadic basis. Usually I just work the pin back and forth a bit and maybe comment on the compressor's ancestry a time or two and then all goes well for a time.

Really should have no complaints on the compressor as it has many many hours running time on it.

 

[studor]

Sometimes the popoff valve can be locked open -- as Egon says a twist will usually close it

 

[grsthegreat]

you havnt stated what the pressure is when the main pressure shut off switch stops the compressor. if its too high, then the pop-off valve will naturally cycle. If it is not too high, then its the pop-off valve. ive seen these at any compressor shop. pretty cheap part

 

[IXLR8]

I had a CH compressor that did the same thing after owning it for a few years. The shut off switch was not activating soon enough and the tank was going over pressure. I pulled the regulator/switch apart and found the pressure switch was adjustable. The adjustment is under a sealed plug, but it was easy to remove. Adjusted it down a bit and it has been working fine for 2 years.

 

[SPYDERLK]

No, the air is coming from the check or emergency popoff valve that is up near the controls. Sorry, should have included that. Can that be replaced, is it just a bad seal, bad valve or what?

If the popoff is operating I dont see why the compressor would turn off. It sounds like an unloader bleed valve problem combined with a malfunction of the check valve that is supposed to keep tank air from coming back to the compressor.
larry

 

[Egon]

I pulled the regulator/switch apart and found the pressure switch was adjustable.

Yea, mine got pulled apart to adjust the pressure. It was the putting it back together that required ordering a new switch!

 

[MikeA57]

I did some more checking and the compressor shuts off when the tank pressure reaches 120 psi. The air bleeds out from under the Auto/Off switch that's at the regulator. Once the tank pressure reaches 100 psi the compressor kicks back on.

On the switch itself, where the pressure sensing tube that feeds the tank pressure gauge there was a heavy piece of plastic that looked like it was acting as a seal where the feeder goes through the switch body and into the gauge. It felt like the air was coming out of that seal, so I took the switch off and checked it out and the "seal" was torn and tattered. I figured that might have been the problem so I found some thin pliable rubber and made a new seal. I put it on but it still did the same thing. I've got a picture that shows the switch and the old seal but I can't get to it now. I'll post it in the morning.

[EDIT]
I got the photo added that shows the Plastic seal and the Auto/Off switch. The only place the air could be coming from is from around that switch where the air goes in the display on the tank pressure gauge. I guess the new seal that I make was a little to loose to keep all the air in. I guess I'll take that switch off again and put a bead of caulk around the nipple where it goes into the pressure gauge and see if I can't get it to seal. Or, maybe a rubber gasket. I'll bet its supposed to have one around it.