handsome devil
Hot Rolled
- Joined
- May 4, 2005
- Location
- Bonduel, Wi
Have a towable compressor that was not releasing or stopping pressure build up when air was shut off. From my reading and talking with other people was suggested the problem lies in the Subtractive Pilot Valve {SPV}. My understanding when working properly this sends the signal to the inlet valve {which acts like the unloader} which opens of closes the valve to compress air or release compressed air. In my eyes it could be either of the two valves causing the over pressure. This compressor is a Gardner Denver 125 cfm screw pump, gas engine model from 1973 era. My operators manual from my personal GD 150 cfm compressor is from 1969 but is essentially the same compressor. My book and others have pointed to this SPV as the probable culprit.
My question is can these be tested or rebuilt or even taken apart and cleaned up and then tested? The parts is approx $150 range and have no problem changing it out but hate changing parts out that are not bad and basically wasting money. Guess I got nothing to lose by attempting to take apart and clean up, but is there a procedure for testing them. Wonder if they are calibrated from the factory or does the operator do it off the air pressure gage on the machine? Nasty storm at the moment and don't feel like experimenting with this in my unheated shop today. Anybody know any of this?
There is a spring and piston in the inlet valve that could also be the problem as I mentioned already. Starting here as this was where it was recommended to start. Got a sneaking hunch I will be going into the inlet valve before I am done with this. This is why I wonder if this can be tested on the bench or not? This compressor is owned by a non profit so I am trying to fix this without wasting money changing out parts as a way of trouble shooting. Even though that is the modern American way of doing things. Just give the bill to the boss right? Thanks, John.
PS I know in the recent thread on the "old Worthington Compressor" he found the unloader froze up. So I am not totally sold on the SPV being the issue. Wish that thread would continue on with progress updates. Two totally different machines but both having similar problems with unloading. The compressor I am working on at non profit is outside buried under a tarp in a snow bank at the moment and was lucky to get the SPV removed before this last storm hit. The access door was conveniently accessible without having to remove the tarp. Working on either of these compressors outside or unheated shop is a pain. If I can get this small part figured out now, is one less thing to do come warmer weather and be in competition with other projects that are also on hold.
My question is can these be tested or rebuilt or even taken apart and cleaned up and then tested? The parts is approx $150 range and have no problem changing it out but hate changing parts out that are not bad and basically wasting money. Guess I got nothing to lose by attempting to take apart and clean up, but is there a procedure for testing them. Wonder if they are calibrated from the factory or does the operator do it off the air pressure gage on the machine? Nasty storm at the moment and don't feel like experimenting with this in my unheated shop today. Anybody know any of this?
There is a spring and piston in the inlet valve that could also be the problem as I mentioned already. Starting here as this was where it was recommended to start. Got a sneaking hunch I will be going into the inlet valve before I am done with this. This is why I wonder if this can be tested on the bench or not? This compressor is owned by a non profit so I am trying to fix this without wasting money changing out parts as a way of trouble shooting. Even though that is the modern American way of doing things. Just give the bill to the boss right? Thanks, John.
PS I know in the recent thread on the "old Worthington Compressor" he found the unloader froze up. So I am not totally sold on the SPV being the issue. Wish that thread would continue on with progress updates. Two totally different machines but both having similar problems with unloading. The compressor I am working on at non profit is outside buried under a tarp in a snow bank at the moment and was lucky to get the SPV removed before this last storm hit. The access door was conveniently accessible without having to remove the tarp. Working on either of these compressors outside or unheated shop is a pain. If I can get this small part figured out now, is one less thing to do come warmer weather and be in competition with other projects that are also on hold.
