reconnecting a compressor ~ an extra air line???

by steve
(douglas,ma)

I have a 60 gal 5 hp single phase compressor (energair) i bought at an auction. It has a 1/2" copper line off the compressor head to a tee in the tank. Off of this tee is a automufler that has a 1/4"copper line about 12 " long that i do not know where it goes. There is a pressure switch attached to the tank. both nipples going into the tank,one for the supply from the compressor and the nipple from tank to pressure switch have a 1/4 " copper refrigeration tube connecting them near the tank. Where does this 12 " line go to and can I just remove it and plug the tee?


_________________________
Bill says...

Steve, it's very difficult to be sure without seeing the set up.

I think that the line that ends up nowhere may have connected to an unloader valve.

You can try blocking the line and letting the compressor run up to the cut out pressure level. If it does that OK, then slowly bleed air from the tank until the cut in pressure level is reached.

If the compressor tries to start and cannot, that would support the "missing unloader valve" theory.

Good luck. Keep us posted, wont you?

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Has Unloader Valve Issues.

Pressure releife on cylinders

by carroll
(garland texas USA)

after the initial build up of air shuts off and you have a call to start it will not start apears to be under pressure

________________
Bill says...

Hi Carroll:

If I'm understanding correctly, your air compressor reaches cut out pressure, stops, and after you use air and the pressure drops, your compressor can't re-start?

Pull the plug and then drain the tank to zero.

Plug it back in (after closing tank drain valve). Does it start OK?

Now, listed to the small valve near the pressure switch. When the pressure switch shuts off, that valve should dump air. If it does not, then you need to clean, fix or replace your unloader valve.

See Unloader Valve linked from the Valve page for more info.

Cheers,

Bill


Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Has Unloader Valve Issues.

Failing to start under pressure

Compressor will start and pump up OK, but once it needs to start again, it sounds like it is struggling and won't start. Letting the pressure down will allow it to start again.

___________________
Bill says...

G'day, and thanks for writing in.

Go to the VALVES page, and click on the UNLOADER VALVE link.

Your symptoms are classic for an unloader valve that isn't working.

Cheers,

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Has Unloader Valve Issues.

Gardner-Denver 75HP Electra-Saver II Screw Compressor has "flutter" in unloader valve

by Phil
(Pittsburg, KS)

My shop has a G-D 75hp Electra-Saver air-cooled screw compressor. It normally runs fine, but occassionally it develops a flutter that appears to be coming from the unloader valve, but I can't figure out what would be causing this.

If you shut down the machine for a while and let it cool it will go away, but eventually it will come back. We had it shut down for a couple of weeks straight, then brought it online a few days ago and today it started it again.

Do you think you can help me on this?

______________
Bill says...

Phil, even though my name is Bill, I have to be Frank with you... :-)

No, I don't have any idea what may cause this. A 75 HP compressor is a pretty complex beast.

I am hoping that some of the very knowledgeable people that read the pages on this website can help, though.

How about it folks, any idea what may be causing Phil's compressors unloader flutter?

Thanks much,

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Has Unloader Valve Issues.

Air compressor

by Bob Newman
(Colborne,On. Can.)

Is a bleeder valve and an unloader valve the same thing on a pressure switch??

____________________
Bill says...

Howdy Bob. Sure sounds like the same thing to me, though I'd like to know the context before stating for sure.

Who refers to it each way?

Cheers,

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Has Unloader Valve Issues.

New Unloader Valve (for home modified compressor)

by Brent Blevins
(Texas, USA)




I have two old compressors that I found on trash day. One had a bad tank (horizontal Model #919178410 from Sears made by DeVilbiss), and the other had no power head (vertical Campbell Hausfeld not sure of the model number). It is a Frankenstein, and an ugly one at that but I am only out the price of the soft copper tubing I had to bend...

I cut the mounting plate off of the horizontal tank and placed it on the vertical tank. I had completed plumbing everything and was ready to test.

As the pressure came up, I realized that the nut for the compression fitting to the unloader valve were loose and it seemed to be leaking. When I tried to tighten them, the valve snapped in half. I do not want to but a whole new pressure switch for $70 from Sears. Do you know of any sources to buy just the unloader valve?

_____________________
Bill says...

Congrats on some excellent working, putting two older compressors together to form a Frank... er... compressor.

Although $70 seems to me to be a pretty good price for a compressor, I do think if you shop on line you can get a pressure switch and unloader valve combo for less.

Failing that, I don't have any sources in Texas... but I'm sure some of the visitors will. H

Thanks for the photos..

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Has Unloader Valve Issues.

My compressor won't refill if there is any air in the tank.

by Bill
(Baltimore, MD)

I have a Hitachi EC12 portable air compressor, and it fills fine initially, but once some pressure is used and it tries to refill the motor tries, but can't get enough momentum to build pressure, and ends up popping the breaker.

I read a similar scenario on here that makes me think it is the Unloader Valve, but I'm not sure. There was also something about a Check Valve???

____________________________
Bill says...

Hi Bill. Go back to the Troubleshooting page, and visit both the Check Valve and Unloader Valve pages for detailed information on both, how they operate, and what they do.

From the information you have provided, I think that your self diagnosis of an unloader valve problem may be spot on.

I don't believe it's a check valve issue, though reading both pages will provide enough info to allow you to check.

Cheers,

Bill

Click here to read or post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Has Unloader Valve Issues.

After initial and complete pump up, compressor seems to lug when drained

by Chris Manescu
(San Diego , Ca.)

I have an Ingersoll Rand compressor and when I turn it on, it pumps up to about 150 PSI. When I start to use it and drain some air off, it seems to try and re-start, but drags as if the motor is pulling too many amps. It even trips my house breaker.

I loosened the outlet line at the compressor head and it will start and pump as long as air can bleed past the fitting. As soon as I tighten that fitting, it seems to "lock up".

The shut off relay seems to be working, but I am at a loss to why, when there is any kind of a load with some air in the tank, it will not restart. If I drain it down to around 25 PSI, it will start and pump to 150 psi again.
I inspected the check valve in the tank and it appears to be free of any damge or restriction.

_______________________
Bill says...

Chris, it sounds as though your compressor is lugging on start up, since it sounds like it's trying to start against load, and the load is too great.

When a compressor reaches cut out pressure level, there is almost always pressure left over the piston. The motor cannot start against this pressure. The pressure has to be bled off.

That's where the unloader comes into play, and I think this is your problem.

Please go to the nav bar, click on valves, and follow the link to the Unloader Valve page. Have a read of this. I believe this is your problem.

If this doesn't resolve the problem (fixing the unloader valves) please post another comment on this thread, and we'll try to figure out what else is wrong.

Cheers,

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Has Unloader Valve Issues.

Coleman Powemte mode# BL0603310.01 made 3-22-2001

by Joe Brown
(Pieville Ky U.S.)

At first I thoughtthe comapcitor was bad because after the air would build up and kick off, it would attempt to kick on again to rebuild pressure the breaker ( in the house) would kick. Causeing power failure inside our home.

However I took the both compacitors to the mines where I work and tested them, both were working correctly.

So a couple of electricians I work with suggested that my problem was the reed valves.

Could this be the main problem? Or could it be a diffent part? If it is a reed valve where can I purchase them for this model? Every store or web site I have browsed does not carry them for a powermate this old.

_____________________
Bill says...

Hi Joe. Before you go chasing down the valves, let me ask you, when the compressor reaches cut out pressure level and shuts off, does it unload?

Let me try another question. If you turn it off, drain the tank to zero pressure, close the drain, turn it back on... does it start without blowing the breaker?

If it does, have a look at the Unloader Valve page linked from the Valves page.

If it still blows the breaker with zero pressure in the tank, then, I suppose it's possible that it could be the valves... but I would be more inclined to look at the motor next.

Keep us posted, K?

Cheers,

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Has Unloader Valve Issues.