# Head pressure won't unload



## Gsxr11001990 (Jun 11, 2017)

I have a powermate model VLP1581727 that I obtained broken as a project. The piston on the compressor motor was broken. I obtained a piston and head repair kit for this model and figured that would be it. HA! I believe I found why the piston broke but I'm unsure how to correct it. After several attempts I concluded that the head pressure isn't unloading. I don't see how it would unload on this particular model. It has a pressure switch, obviously, and a check valve, again, duh, but nothing linking the 2. How does the head pressure get unloaded? Does it even matter for this model? Am I looking at a check valve problem only? Basically, what it does after start up, it builds to cut-off pressure than stops. No air is released. If you draw air from the tank, the pump kicks back on but the piston will not move. The belt just starts screeching and smoking. I have drained all the air out and repeated the process a few more time before I realized the piston is pushing against something that it can't move. Since there is no mechanism I can see for unloading the head pressure, again, am I looking at a check valve that's sticking? Also, is there a way I can change the pressure switch on this model to one that I can use to unload head pressure by running a line to the check valve? The check valve on this model does have a 1/8 port on it that isn't used, it's currently capped. Thanks for any help or ideas anyone can offer. Here is a link to the manual and parts list for this model. Power Equipment Forum : Power Equipment Forums - Post New Thread


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## Gsxr11001990 (Jun 11, 2017)

Power Equipment Forum : Power Equipment Forums - Post New Thread


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## Gsxr11001990 (Jun 11, 2017)

Here is the link to the manual. http://www.powermate.com/airproducts/pdfs/air_compressors/VLP1581727.pdf


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