Yes, another failure to prime post

[Frankw1]

I'm having a problem getting pump to prime.

It has been cold lately - getting down into low 30s occasionally hitting upper 20s. Last week on Wed or Thurs I noticed that the freeze protect on my waterfall pump turned on during the night, but not for the main pump. When I woke up, the main pump was running but wasn't pulling water. I primed it and it began pumping.

Then the next night same thing. Main pump was running when I got up but no water flow. Now I can't get the pump to prime. Made sure the lid was secured tightly. The pump sucks water out of the basket rapidly, but doesn't pull from the pool after running for several minutes.

Pump for waterfall works fine.

What I've done.

Cleaned and lubed the O-ring on the lid. Cleaned and lubed the top of the pump basket to make tight contact with o-ring. Nothing. Swapped pump lids from waterfall pump (since it was working). Nothing. To isolate issue with skimmers, ran pump with line to one skimmer closed. Nothing. Opened that one and ran with other skimmer line closed. Nothing. Checked all connections and tightened. None were loose. Observe no water leaks on concrete pad.

What I'm observing

Pump sucks water from basket quickly (so seems to be working properly) but doesn't pull from intake after running for several minutes - no water flowing through pump. I'm noticing bubbles coming from jet closest to pump which seems to indicate air getting in somewhere. Checked and tightened all connections. None loose. No activity at either skimmer or at bubbler fountain.

Any ideas? Anything else I can try?

My concern is that now nights are getting down into upper 20s, low 30s and now water flowing through main pump at night. And another arctic blast is coming this week.

Any ideas? Suggestions?

I've attached a photo of my setup showing positioning of valves how I typically run it.

 

[ajw22]

You have three suction lines and the two valves give you control over them.

Have you turned off two of the suction lines to see if your pump primes with each line individually? That will let you isolate if the air leak is in a specific line.

If the pump fails to prime from any of the lines individually then we can rule out the lines and the problem is between the valves and the pump.

You can wrap Saran Wrap around the valves and pump. The Saran Wrap should get sucked into any air leak and allow the pump to prime.

Why do you have all the valves not opened fully on the suction lines?

 

[wireform]

The check valve on the suction side maybe jammed. I'd open the spigot on the pressure side of the pump just to see if it'll prime faster then close it to see if it'll continue.

 

[Frankw1]

You can wrap Saran Wrap around the valves and pump. The Saran Wrap should get sucked into any air leak and allow the pump to prime.

Well AJW, you win the prize. Your saran wrap suggestion is a master level hack... and it worked like a charm. Thank you so much. Pump now primed and running.

Unfortunately, I wrapped the check valve and nearby connections with the pump off, so not sure exactly where the leak is. However, I will remove it in sections to reveal. I suspect it is the check valve right before pump.

My battle is only half over as I will more than likely need to change out that check valve.

 

[wireform]

See what the issue is with the cv as part kits are available. If there's a crack in the black part then you'll need to replace the whole thing but the cover and seal and inwards are available.