10-07-2014, 11:11 AM
Bill: first let's make sure there isn't a leak that is nearly equal to the output of the 120vac pump. You say the engine pump will bring up pressure quickly. Once pressure is up, how fast does it leak down. If fairly fast (highly technical scientific terms) you have a leak that needs fixing. If it drops slowly then you most likely have a supply problem.
If you can make a direct air connection between the pump and the pressure switch, also eliminating the tank, you can then fire up the pump and see if it reaches shutoff pressure and, if it does, how long before it kicks in again. If it kicks in fairly (that scientific word again) then the valves in the pump are having a problem. If it behaves well, then you need to go through the peices you bypassed and find the one that's restricting flow.
Another way to get a very rough measure of what the pump is doing is to measure amps to the motor and compare that to any data on pump performance that's available. Low amps would indicate the pump ain't apumpin.
Hope this helps
If you can make a direct air connection between the pump and the pressure switch, also eliminating the tank, you can then fire up the pump and see if it reaches shutoff pressure and, if it does, how long before it kicks in again. If it kicks in fairly (that scientific word again) then the valves in the pump are having a problem. If it behaves well, then you need to go through the peices you bypassed and find the one that's restricting flow.
Another way to get a very rough measure of what the pump is doing is to measure amps to the motor and compare that to any data on pump performance that's available. Low amps would indicate the pump ain't apumpin.
Hope this helps
Jon Kabbe
1993 coach 337 with Civic towed