Posted by: Rangr90 ® 03/26/2007, 21:18:09 Author Profile eMail author Edit

I have a old Sears air compressor made in 1968 it has about a 40 gal tank and a twin piston pump with a centrifugal unloader on it. What it is doing is at about 100 psi it starts to labor and spit air out the filter nut on the centrifugal unloader. It always would run up to 150 psi and shut off without any problem. Does anyone know what would cause this problem????? Thanks Rangr90

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Re: Help!! Old Sears air compressor!!
Re: Help!! Old Sears air compressor!! -- Rangr90	Post Reply	Top of thread	Forum

Posted by: randykimball ® 03/26/2007, 23:22:19 Author Profile eMail author Edit

Had the same problem once... I unplumbed the centrifugal unloader and put one that is a check valve and unloader combo in the line between the compressor and the air system. This lets the compressor be unloaded for start-up after it cycles off. What happens is: the compressor shuts off when the control meets set value. The air tries to back through the compressor and the check valve seats. Then the unloader port opens and lets all the compression out of the compressor and line up to the unloader. You can buy one from most any major catalog house for a few dollars and they come in several pipe sizes. The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.

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Re: Re: Help!! Old Sears air compressor!!
Re: Re: Help!! Old Sears air compressor!! -- randykimball	Post Reply	Top of thread	Forum

Posted by: Rangr90 ® 03/27/2007, 15:35:16 Author Profile eMail author Edit

Thanks for the respronse. Where do i disconnect the centrifugal unloader and add the check valve?? I'm a little lost on this. Where do i buy the check valve from?? Thanks Rangr90

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Re: Re: Re: Help!! Old Sears air compressor!!
Re: Re: Re: Help!! Old Sears air compressor!! -- Rangr90	Post Reply	Top of thread	Forum

Posted by: randykimball ® 03/27/2007, 16:39:12 Author Profile eMail author Edit

This is hard to explain. You should have some kind of a fin stacked tube between stage one and stage two. Then you should have an exhaust from stage two to some kind of entrance into your unloader. There is an exhaust from your unloader which feeds your main air system. You want to connect directly from the second stage exhaust into this new "Genie unloader and check valve" entrance side and connect your air system to the exhaust side of it, instead of your old unloader. Sometimes the new Genie needs to be oriented with gravity a certain direction, read the instructions. When you have done this it is sometimes necessary to connect the old unoccupied entrance and exhaust of the old unloader with a short loop of tubing to seal it off. Yours may vary... but as I remember this is the main idea... OK? You get the Genie Unloader & Check Valve from major commercial catalog or supply houses for around $12 to $20. The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them. Modified by randykimball at Tue, Mar 27, 2007, 16:42:34

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Re: Re: Re: Re: Help!! Old Sears air compressor!!
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Posted by: Rangr90 ® 03/30/2007, 20:59:38 Author Profile eMail author Edit

Thanks Randykimball I'm hoping to work on it this week end. Rangr90

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Re: Re: Re: Re: Re: Help!! Old Sears air compressor!!
Re: Re: Re: Re: Re: Help!! Old Sears air compressor!! -- Rangr90	Post Reply	Top of thread	Forum

Posted by: Rangr90 ® 04/02/2007, 20:17:11 Author Profile eMail author Edit

Well i was just about to give up on that old compressor when i tighten the belt and guess what that was it the compressor works just like it did when it was new. By tightening the belt now the unit dont labor which is when the belts were sliping and the unit was trying to let air out of the lines like it should when it shuts down. Thanks to everyone for there help. Rangr90

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Posted by: randykimball ® 04/02/2007, 23:05:46 Author Profile eMail author Edit

Again the simple fix shows its face. That is great. Was much easier too, wasn't it. And ya know? ... it makes good theory. The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.

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Re: Re: Re: Re: Re: Re: Re: Help!! Old Sears air compressor!! -- randykimball	Post Reply	Top of thread	Forum

Posted by: Kelly Bramble ® 04/03/2007, 08:52:10 Author Profile eMail author Edit

When all else fails "Tighten the Screws!" Is that how the saying goes? Aren't you glad you came to a engineering site!

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