Air sucked into filter canister

[CatGrandma]

New pool owner here. Old pool, old equipment.
We are experiencing air leak, on suction side, I think. The filter canister seems to bubble with incoming air when the pump is shut off, and has to be bled to get suction at vacuum port.
Also unable to separate skimmer and vacuum, which is a new development. Pool store suggested the first 3way valve diverter was bad.
All 3 valves have had diverters and o-rings replaced, as a first step elimination. But air still collects.
This seems to be a tangled mess, that I am hoping to replumb, without all of the elbows. It looks like previous owner has already added and subtracted at the valves, making use of adapters, so I'm thinking we will need to replace the valves, anyway. Yes?
Looking for advice that isn't super expensive.
Thanks in advance!

 

[Texas Splash]

Welcome! You're right, you have quite a challenge there, but certainly manageable. To recap, if the pump pot is showing signs of air under the clear lid while the pump is on, then it's a suction side air leak. If air goes into the pump pot and water moves around when the pump is turned off, then the air leak could be anywhere on that pad - suction or pressure side.

That said, every joint, union, bulkhead fitting, and valve is suspect at this point. I would start at the pump and work my way backwards. Lid O-ring serviceable and lubed. At the pump entrance, check that union nut to ensure the O-ring is lubed. The O-ring should provide a good seal, but you might place some sealant on the threads as well. From there, work backwards to that 3-way valve to ensure all those O-rings were lubed as well. Inspect for cracks. That's all I see for suction side stuff on the pad.

Pressure side, you may not always see a water leak, but air can still get sucked "in". The filter pressure relief/gauge is a common spot. The filter bulkhead fittings could also be an issue.

I agree that once you decide to operate, you could clean-up that IH-10 interchange of piping to make life much better. Hope that helps.

 

[CatGrandma]

Thanks for the quick reply!
When the pump is first turned on, it partially primes. It loses some - less than a third- water as it sits, but never empties.
Once air is bled from the canister, the pump fills completely and runs full until the pump turns off.
That's when you hear gurgling in the filter canister, and the whole thing starts over again. We have stopped the auto timer on the pump, so as not to burn up the pump.
Replaced O-ring on pump basket at beginning of season, and cleaned and lubed regularly. The pressure gauge is also new, and doesn't show a leak with incense, shaving cream or water. But easy enough to redo.
Union O-rings look and felt good - no black transfer- and fit into groove without any distortion, and are also lubed. Nuts snugged down with teflon tape the first time, then with thread seal the second time.
All of the valve Orings were lubed as they were replaced. No visible or palpable cracks are in/on the valves, but new multi port valves are on order for replumb.
The Oring around the middle of the filter canister is also new, and is lubed at every cartridge change.
I was considering caulking pvc joints with silicone - since they will be replumbed anyway, just to see if there is a leak not detected with incense, shave cream or hose water. Good or bad idea?
Also, can you explain bulkhead fittings? Where and what are they?
Thanks!

 

[Texas Splash]

Also, can you explain bulkhead fittings? Where and what are they?

The nuts that connect the in & out plumbing to the filter.

 

[CatGrandma]

Oh!! Those. I haven't been able to break those loose with a strap wrench, and am leery to use a pipe wrench. Again, nothing detected with incense, shave cream or running hose.

I am attempting to match replacement unions and those bulkhead fittings, in preparation for the replumb project, but not having much luck.
Thanks again

 

[sande005]

Also - if you can, try shutting off selected suction lines (skimmer, main drain, etc.) one at a time. If finding one resolves the air leak issue, then likely the problem is between that valve and the other end (skimmer, drain, etc.), potentially eliminating a lot of sleuthing that doesn't need to be done. If no change, then it more likely is from the valves or the rest of the lines to the pump. (but not definitive if the valve is leaky and still allows water/air to still suck from its source even when closed).

Pricey for this use, but I used this to wrap my pipe joints temporarily to seal, so I could see if something was sucking air that way. Stretchy and rubbery to mold to the joint, and adhesive to stick to it. Not something I would trust to fix an issue, but for testing....Scotch 1 in. x 10 ft. x 0.065 in. 2228 Rubber Mastic Electrical Tape, Black 50727-BA-5 - The Home Depot

 

[CatGrandma]

Also - if you can, try shutting off selected suction lines (skimmer, main drain, etc.) one at a time. If finding one resolves the air leak issue, then likely the problem is between that valve and the other end (skimmer, drain, etc.), potentially eliminating a lot of sleuthing that doesn't need to be done. If no change, then it more likely is from the valves or the rest of the lines to the pump. (but not definitive if the valve is leaky and still allows water/air to still suck from its source even when closed).

Pricey for this use, but I used this to wrap my pipe joints temporarily to seal, so I could see if something was sucking air that way. Stretchy and rubbery to mold to the joint, and adhesive to stick to it. Not something I would trust to fix an issue, but for testing....Scotch 1 in. x 10 ft. x 0.065 in. 2228 Rubber Mastic Electrical Tape, Black 50727-BA-5 - The Home Depot

Thanks for the reply!
We still have to identify which is controlled by what. We thought we had it figured out, but as now we cannot separate the vacuum port and skimmer suction, guessing the 3way valve has failed, even with replaced diverter and Orings.

Tape was a great idea!
But I spent this afternoon using silicone caulking around joints, seams and possible leak points, since we will be replumbing anyway.
Going to let it cure overnight, and test tomorrow.
I will post an update.
Thanks!

 

[tcross04]

Gurgling only after the pump shuts off sounds like a pressure side leak. However, best to rule one out at a time.

With the pump running, take your running garden hose over every fitting, o-ring, or other weak spots to see if there are fewer bubbles entering the pump. Normally, with suction-side leaks there’s a flurry of bubbles. Take your time. The bubbles sure even out. Also, make sure that it’s not your pump cavitating (not getting enough water to supply its demand.)

Once you’ve ruled those out and it’s only struggling at startup then start trying to find the pressure side leak. Start at the top-most part of the plumbing system, often times the top of the filter. Grease all your o-rings. Don’t forget the air relief valve at the top of your filter. Grease the o-rings for any diverter valves and screw them down nice and snug…

Hopefully this helps!

 

[CatGrandma]

Gurgling only after the pump shuts off sounds like a pressure side leak. However, best to rule one out at a time.

With the pump running, take your running garden hose over every fitting, o-ring, or other weak spots to see if there are fewer bubbles entering the pump. Normally, with suction-side leaks there’s a flurry of bubbles. Take your time. The bubbles sure even out. Also, make sure that it’s not your pump cavitating (not getting enough water to supply its demand.)

Once you’ve ruled those out and it’s only struggling at startup then start trying to find the pressure side leak. Start at the top-most part of the plumbing system, often times the top of the filter. Grease all your o-rings. Don’t forget the air relief valve at the top of your filter. Grease the o-rings for any diverter valves and screw them down nice and snug…

Hopefully this helps!

Thank You!! The manual bleed valve at the top of the filter canister had bad O-rings. Replaced, lubed and problem solved!