Jabsco water pump won't shut off

[Musicaltrees]

Question for help please! My Jabsco 2.9 water pressure pump continues to provide great water pressure for both sinks. However, now the pump will not stop running when I turn the facet off. Now I have to shut it off at the breaker each time I use water pressure. Is this what happens when it needs to be replaced? Or could there be an easy fix by taking it apart and checking the diaphragm? I have a new replacement on hand but if anyone has any suggestions to consider first please advise. Thanks from SV/Glory Days.

[motion30]

Sounds like a defective pressure switch . they are available separately and not difficult to install

[Ulstue]

AFAIK a defect pressure switch would usualy not start the pump. If the pump does not stop, it could be that there is a relay befor the pressure switch that is defekt. Often this relay is "mobil home" and not "marine" grade. Often it is unnecessary.

[FlightPlan]

Perhaps the accumulator tank has lost pressure.

[Musicaltrees]

Motion 30 you are exactly right!!! I "borrowed" the pressure switch from the new unit and the problem is solved. You just saved me some bucks. Thank you for the worthy tip!!! Joe

[sv_itsallgood]

Originally Posted by Ulstue

AFAIK a defect pressure switch would usualy not start the pump. If the pump does not stop, it could be that there is a relay befor the pressure switch that is defekt. Often this relay is "mobil home" and not "marine" grade. Often it is unnecessary.

I had a similar issue with the relay. I was lucky and was able to just reset it (unplug and replug) to resolve the issue. No issues since.

[topmast]

The end result of not shutting off can be the complete burn out of the pump motor. The micro switch is usually the short lived culprit ,easily replaced. And a nearby accumulator will assist it in living longer ,,, less cycles and less flutter as pressure maxis. Bunged accumulator only effects number of cycles ,nothing more.

[DennisRyan]

Those pressure switches are generic and available at Graingers for cheap money - buy a couple.

[Waverly]

I had a similar problem and I found that the filter screen before the pump needed to be cleaned out. It was clogged and would not allow enough water to flow through it

[jimthesail]

Ahoy !
Had same problem cured by disassembling switch (two Pozidrive screws under blue cap). Between power leads is another screw with two nylon washers. My 'take' is that this screw is adjusted in factory by a spacer between the washers or their pressure checking supply is faulty (I don't in fact believe they are checked by pressure ?) Testing the switch by finger pressure and a continuity tester I found the adjustment very 'iffy. Either something or nothing ! Switch is sealed and suspect contains an over centre device which is manufactured to trip at,say,20psi. Tuned it to trip at lowest possible pressure and eureka, it works well. There is also a small finned 'spinner' in the void above the switch which I may have disturbed too ? Don't quite see what relays and accumulators have to do with the problem, if the pump has a good supply it will either explode calorifier, burst pipes or put taps into orbit ! It does not know what is ahead, only the pressure difference between the vanes and the switch diaphragm ? Beware the diaphragm can go in upside down easily causing a leak !

[topmast]

Yup, probably the microswitch. If stuck for source, most dead microwaves ovens have at least three of them ,probably the same model. Tube and cup bilge pump sensors the same behind the diaphragm. Hope the motor didn't overheat.