Air in pump

[JKH]

I am seeing an air pocket in the clear plastic pump basket lid. When I move both skimmer and floor drain towards the closed position I see a large volume of air bubbles accumulate. I never run in this configuration, just did this to test for suction leaks. Can anyone explain a probable cause and a remedy?

 

[Texas Splash]

When you close both suction lines, you are placing a very strong pressure demand on all seals. It may just be squeezing the O-ring under the clear lid (or drain plugs) more than normal allowing air in. Possibly any other fittings (adapters, valves, etc) before the pump. For the normal, small amount of air you were seeing, I'd start at the O-rings to ensure they are lubed well. A small bubble or two under the clear lid isn't going to hurt anything. It's when the water level drops significantly and the chance of losing prime to the pump increases that we get really concerned.

 

[Homebrewale]

Have you tried to see where the suction leak is occurring?

 

[JKH]

Thanks for the reply. Yes, I'm aware that a lot of suction was applied to the fittings as that was my intent to try to find the leak allowing air to enter the pump. It seems like the installer who put my pool plumbing together saw a need to plumb it in a way that enabled all three of the valves to be closed on the suction side. Doesn't make sense to me. The photo shows the 3 valves from left to right, suction line for pool cleaner, skimmer and main drain. This photo was taken right after the filter was cleaned and a water test as shown by Homebrewale. I also removed the o ring in the pump cover, inspected and cleaned the groove, inspected the ring and lubed it with "Lube Tube" with PTFE then inspected and cleaned the pump housing mating surface. After starting up, the air in the lines was purged and normal operation resumed, except for a small amount of air in the pump lid. It's not very clear in the photo. This was never apparent and I only noticed it a few weeks ago.

A while back, maybe 2 months ago, I was away for a few days and when I returned I noticed the water level had dropped below the weir in the skimmer and a lot of bubbles were coming back through the return openings. I immediately shut off the pump and added water to bring it up to it's normal level. The pump starts at 10 AM and stops at 6 PM, daily When I restarted the pump a new noise was apparent. It wasn't extremely loud but very noticeable and it seemed to come and go. The noise is still there now but only sometimes. My question is, can air make it's way to the pump housing from the motor shaft and how can I inspect it? I suspect a failed seal in the motor shaft.

 

[Texas Splash]

So it appears you made good progress to lube the O-ring and only see a small amount of air under the lid now. As for any potential damage from the pump running dry previously, hard to tell. Perhaps the seal plate got hot and that needs to be addressed? But if it's a tiny, tiny amount of air, I would just watch it for a while.

 

[JKH]

Thanks for your help. I will do that.