Shower sump pump not pumping

[Todd j]

I have a rule shower sump pump.  It is in my bilge under my galley sink beneath a hatch.  I have tested it a few times since the wiring was completed.  It has worked flawlessly.  Yesterday I washed the boat and began moving in galley supplies.  I filled the water tank and was using the sink quite a bit to rinse dust from my rag.
  I noticed the pump running but it sounded like it is running dry.  The sump was full and beginning to over flow.  I pushed the float down by hand and the pump turned off.  I  released the float and the pump turned back on and pumped the water as expected. 
   The float works properly and starts the pump as it should.  Sometimes the pump fails to “grab” water.  It does seem odd to me that every time this happens if I cycle the float as described above the pump will get traction.  It happens every time without fail. 
   Suggestions please!   I have the surveyor coming in a week and need the new stuff to work like new

[Brian.Dixon]

I don't know anything about Rule pumps, but to me, it sounds like it's losing it's prime (draining dry) between uses and/or there's an o-ring on a piston or something that's not sealing well enough.  I'd seek a pump replacement ...

[Todd j]

I may dig deeper into this today. 
  What is puzzling me is this.   When the water in the sump floats the switch the pump comes on and it pumps water say 20% of the time.  When the sump is full and I use my hand to move the float switch it works flawlessly 100% of the time.   

[Brian.Dixon]

I may dig deeper into this today. 
  What is puzzling me is this.   When the water in the sump floats the switch the pump comes on and it pumps water say 20% of the time.  When the sump is full and I use my hand to move the float switch it works flawlessly 100% of the time.

Could be a flaky float switch.  Like, when you lift the float by hand, you're pressuring it to one side or the other differently than what happens with water lifting it alone.  Try pushing in/out/left/right while raising the float.  I'll bet you discover a direction where it becomes flaky.

[Todd j]

I tried to jigger the float switch and it still works as it should. I’m not sure how likely it is,  it I’m considering whether or not the impeller is spinning on the shaft.   That’s my next project

[Brian.Dixon]

I tried to jigger the float switch and it still works as it should. I’m not sure how likely it is,  it I’m considering whether or not the impeller is spinning on the shaft.   That’s my next project

Interesting ...

[Todd j]

Just a thought.  At this point I think it is plausible, just not sure how likely.  May be that there is piece of debris or something too

[Todd j]

I went through what I thought would  be a warranty PITA with the vendor.  It in turn led me to the manufacturers tech dept.  turns out I just pulled the check valve out of the pump discharge and it seems to be behaving. 

[Brian.Dixon]

I went through what I thought would  be a warranty PITA with the vendor.  It in turn led me to the manufacturers tech dept.  turns out I just pulled the check valve out of the pump discharge and it seems to be behaving.

Seems like you'd want the check valve ... is it defective?

[Todd j]

It was somehow allowing a column of air to air lock the pump in my installation.   He seemed to think it was not necessarily a bad thing to be without it.   At least according to the tech.   I’m not getting a partial refill of the sump when the pump kicks off.  I think I’m happy, at least for now.