Pool pump looses prime within 1 minute of starting pump

  • Last Post 03 June 2020
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Palin123456 posted this 29 May 2020

I have below ground 20,000 gallons of pool. I opened pool last week with lots of leaves and algae. I started pool and did backwash 2 times. Everything was wokring fine and suddedly pool filter was showing reading of zero. I googled it and found that pool pump may be loosing prime. I added water in pool basket, checked o-ring, make sure all valve on suction side are open without any luck. I also checked pool pump propeller and it is without any debris.

What next? Should I call pool leak finding company. My suction side pipe in under concrete so I want to avoid digging that part. Any help would be appreciatred. 


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lwfri1 posted this 30 May 2020

How much above the water level in the pool is the pump inlet pipe. Try priming with a hose rumnnig in the skimmer return.

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Palin123456 posted this 30 May 2020

It is less than 12". Tomorrow morning let me try to prime with a hose in skimmer return, will keep you posted. Thanks. 

Palin123456 posted this 30 May 2020

Iwfri1: your solution worked like a charm, thanks a lot. 

Palin123456 posted this 30 May 2020

Iwfri1: the solution worked for about one hour, and one hour again, and pump stop priming. I also used drain snake from both skimmer side and pool basket side. I didn't see anything clogging suction side. 

lwfri1 posted this 01 June 2020

If your loosing prime you likely have a air leak somewhere. Try to isolate. If possible raise the water level in the pool to help raise the natural level in the pump basket so the pump does not need as much suction to get going.

Palin123456 posted this 01 June 2020

Ok, I will add more water and try that. 

Here is what I tried so far withut success:

  • Insert garden hose on both skimmer and pump basket side
  • Insert drain unclogger (drain king)
  • Insert drain snake from both skimmer side and pool basket side
  • Add bucket of water direclty in pump basket and at the same time pump is running to check is pump is wokring or not, and pump is working.
  • Open Janty valve and make sure there is no obstruction inside
  • Check strainer cover where is leaking or not
  • Use smoke to see wheather air is leaking from fittings
  • Tried new O-ring for pump bakset seal
  • Running pool on re-circulate mode
  • Did bucket test to check water level is lowering and water level maintains. 

After doing above, I called pool guy. Intiallly, without looking anything he said pump impeller is not wokring. Than he opeded the pump and said pump/impeller is perfectly fine. He checked suction line and said suction line is squeezed somewhere becasue I put chlorine tabs in skimmer basket. He said suction line is squeezed so pump will stay prime for about 1 hour and loose prime when suction line is completely squeeze and won't allow any water to flow. He said I have to call another pool guy to check where the actual sqeeze is and do water testing. sorry for long posst.

lwfri1 posted this 01 June 2020

What is the construction of the return line e.g rigid pvc, black pe, ect. I find it hard to imagine that your pump has enough suction to collapse the return line. I see you have a diverter valve directly in front of your pump. Do you have 2 return lines? can you try running the pump with only 1 return line active. Checked diverter valve for air leak?

Palin123456 posted this 02 June 2020

The return line is rigid PVC. I have two return lines, one from skimmer and other vacuum line 2' away and 6" deeper than skimmer.

Here is what I found from some trial-and-error:

With multi-port valve on recirculate setting: If I plug drain unclogger in vacuum line, allow some water from vacuum line to go to skimmer line via with Jantry valve, and then close Jantry valve, allowing water to fill-up pump basket and then start the pump, the pump will prime, suck water from both suction line, and run with full force.

with multi-port valve on filtration setting doing same thing above, and pump will run with full force. After 10 minutes, the pressure gauge will start to go down and within 15 minutes, it will go to zero. At this point, pump is not sucking anymore water from any of the suction line. Then I have to turn-off pump.

Is my pump weak?


lwfri1 posted this 03 June 2020

Maybe, but I'm not sure. Do you have access to and amp meter, the kind that goes around the wire. You have not indicated pump voltage or horsepower so I can't give you a target range. Check both power wire and see if the current changes are pump heats up. Also what's the initial gage pressure, after 10 minutes, and how quickly thereafter.

Palin123456 posted this 03 June 2020

Earlier today, I took apart everhing wahtever I can incluidng filter, multi-port valve, motor, suction line. I cleaned it all and put it back together, put on new pump basker seal, and the pump start to prime and wokring with full force. The pump basket stays full and I don't see single bubble of air in it. I don't know what did the trick but it is wokring now. 

lwfri1: Thank you for your support in this, thanks again.