Discussion Category: Vacuum Pumps
DOA 704 low vacuum, air coming out vacuum side
I'm working on a Gast DOA 704, it pumps some intermittent air out the vacuum side and has low vacuum and no output at the compressor side. I've checked everything. The reed valve looks fine, the diaphram is new, valves are ope and work, gasket looks good. Any help appreciated.
Reply byI fixed the Gast 704 with a piece of .005 SS feeler gauge. The snakebite here is that the reed valve for the suction side is under the valve body, and snaps off at the washer. It doesn't have the SS block the pressure side has. If you don't see it on teardown you won't know the unit must have reed valves on both sides, and you can't quite see it in the drawing in the PDF manual. I used a .005 feeler gauge cut to right length. Drilling is tough, I punched a very small hole first, then drilled the hole for the screw. .005 is a little heavier than the reed valve on the pressure side, but it works fine, and pulls its rated vacuum.