Cannot prime jet pump


  #1  
Old 04-22-06, 08:45 PM
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Question Cannot prime jet pump

Hi,

I hope someone can help us.

We have a Grundfos jet pump (JP-7) at our cottage (double drop pipe). Last fall, we shut down the power to the pump and drained the plumbing but otherwise did not touch the pump. When we went to start it up this spring the pump would turn on but little to no water was coming from the pump. Sometimes pressure would build for a few seconds, but then would go back to zero again and the water in the plumbing line would move backwards in the pipe (back to the pump). When running, fairly large air bubbles were being ejected by the pump with the water. Even with the pump powered off, large air bubbles will still come from the pump, bubbles seen in the line feeding the plumbing.

We were repeatedly priming and starting the pump when we observed this behaviour. Note that when priming, we did not touch the suction line but just primed via the priming plug.

We checked the well and the water level is well above the jet assembly.

Just want to specify that we heated the area where the pump resides all winter long so there was no frost problem. We cannot see any leaks anywhere.

Any suggestions on what could be the problem? And what to try next?

Thanks,
Nadine.
 
  #2  
Old 04-22-06, 09:53 PM
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Does the pump appear to hold water when you prime it? It sounds like you have a bad footvalve, or a leak on the suction side of the pump, which allows the pump to suck in air.
Ron
 
  #3  
Old 04-23-06, 12:45 PM
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Yes, it appears to hold the water when it's primed but we didn't wait a long time before starting the pump again so if there is a small slow leak, we could not tell...

So what would be the next step? look at the suction pipe and add water if need be? What about the 2nd pipe drop? Do we need to prime that too?
 
  #4  
Old 04-23-06, 03:22 PM
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Yes, you need to get as much water in the pump and piping as you can.
Ron
 
 

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