Pump Primiing on and off

[George D]

Hi. Trying to open but having trouble with the pump priming temporarily then losing its prime. Was able to get the water pressure flowing well into the pump for a few hours but it did not fully prime then it lost its prime again. I have the 3 port Jandy valve on Main Drain only and the skimmers are sealed off. I use the poolskim USA device and it has been working well. The MD is clear of any debris.
I don't see any leaks. I added new O-rings to the Jandy valve and to the Union that's directly in front of the pump. I don't notice any air leaks in the pump plugs. Could it be the Jandy valve needs replacement?

It seems my signature is not showing. I'll paste it below.
35k Gal, IG vinyl, Haward sand filter SLE 42084(S244S), Hayward Super Pump 1.5HP, SP1610Z1M,
Laars Lite NG Heater, Taylor k-2006.

 

[ajw22]

I would focus on your skimmer, water level, and weir door when the pump loses prime. You have to be waiting there or setup a camera to record what is happing in the skimmer when the pump loses prime.

 

[George D]

For the past 2 seasons, I had the skimmers turned off and using Main Drain only with no problems. Does using MD only cause a problem in the system?
When I adjusted the Jandy valve earlier, the pump achieved full prime from about 80% prime (10-12 PSI) but then lost it and it has not recovered.

 

[ajw22]

Trying to run only on the main drain can be part of your problem. Main drains can get flaky and clogged. The pipe routing for a main drain is more prone to developing problems. Are you sure no flex PVC was used in your plumbing?

 

[ajw22]

Run PVC above ground from your pump to the pool for some type of skimmer/suction like shown in this thread…

Reviving out of service pool: FG & deck Refresh

I wouldn't hesitate to put on a solar cover with CYA level at 70 & FC of 7. Me either

www.troublefreepool.com

That will confirm your problem is in your main drain suction line.

 

[George D]

Thanks, Ok. I'll need to raise the water level and return to using skimmers & main drain. There doesn't seem to be any debris but it's possible the MD is clogged. Pool needs to clear up more. There is no flex PVC in the plumbing.