Air in pump basket and filter

[robdac]

Newbie here so be gentle.

Pool is at proper water level and the skimmer isn't sucking air but I'm getting air in my pump basket and cartridge filter. So far I've replaced the O ring on the pump basket lid and the O rings on the Jandy 3-way spa diverter valve leading up to it. I lubed the new O rings with Magic Lube when I installed them. I've also removed, inspected, lubed (but NOT replaced) both the pump and pump basket drain plugs.

The pump is a Whisperflo two-speed pump and the odd thing is that it only tends to accumulate air in the system (top of strainer pot and filter) when running on the low setting which shows 7 psi on the filter gauge. High (20 psi) does not accumulate air.

My setup also has three 90 degree Praher ball valves prior to the Jandy valve on the low pressure side of the pump coming from the skimmer, main drains, and cleaner. All are tight now but I can't get to the guts of them without cutting PVC pipes first. Turning any one of these three valves off seems to have no effect on the small amount of air being drawn into the system.

I'm completely stumped as to why I would be drawing air into the system only when the pump runs on low. I'm also stumped as to where the air is coming from. I let the air out of the filter daily and it hasn't yet gotten to the point where it's coming out a pool return but it does accumulate a significant amount in the filter. Ideas? I feel like an auto mechanic just replacing parts to see if it solves a problem.

The attached picture shows my suction side setup. The pump basket typically contains more air than shown in the picture. I had just turned it off of high a couple minutes before I took the picture.

 

[zethacat]

I get air in my basket but it doesn't seem to affect the PSI on my filter. What affect does bleeding the air have on your issue? I've had 2 different pool guys come look at my problem and both told me it's normal, though when I'm priming it looks a lot like the little bubbles are coming from right under the basket lid. Even after pointing that out, an actual Pentair warranty tech says that's not the problem and makes no offer to replace the O-Ring. I guess he's the expert, right?

 

[JohnT]

While it might be that the extra suction when running on high is sealing a leak, there is a good chance that the pump just can't keep up with the flow when running on low.

Try turning some of your return eyeballs 90 degrees so they block most of the flow and see if the pressure rises and the basket fills.

 

[robdac]

I get air in my basket but it doesn't seem to affect the PSI on my filter. What affect does bleeding the air have on your issue?

The basket air doesn't affect the PSI shown on the filter. Bleeding the air just lets the air out of the system (with no pressure change) until the next time it fills up again.

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Try turning some of your return eyeballs 90 degrees so they block most of the flow and see if the pressure rises and the basket fills.

The return eyeballs inside the pool do not slow flow when rotated but I can decrease flow with additional Praher valves on the discharge side so I'll give that a try.

I'm also going to try to rule out the Praher ball valves on the suction side by bypassing them with the Jandy and just circulating water through the spa for a while and see what happens.

 

[zethacat]

there is a good chance that the pump just can't keep up with the flow when running on low.

And that is exactly what the technician told me.

- - - Updated - - -

The basket air doesn't affect the PSI shown on the filter. Bleeding the air just lets the air out of the system (with no pressure change) until the next time it fills up again.

I must not be understanding -- Are you saying that the air in the pump basket disappears if you bleed the filter while it's running? I just tried that on mine but there is still air in the basket.

 

[robdac]

I must not be understanding -- Are you saying that the air in the pump basket disappears if you bleed the filter while it's running? I just tried that on mine but there is still air in the basket.

No, I write poorly. Sorry. The air in the basket remains when I bleed the filter. Bleeding the filter only removes the air in the filter. Turning my pump on HI does, however, clear the air in the basket lid.

 

[duraleigh]

My "guess" is that the extra suction when switched to high is sealing a leak.....as JohnT says.

That's often confusing because the precise opposite can occur also......increased suction can create a leak that was previously sealed when pump was on low.

Anyway, the most likely culprit is always the 0-ring on the pump strainer basket.

 

[Jabooh1]

I have roughly that amount of air accumulate in my pump when the unit is off for a few hours or more. The pump never drains all the way and the air disappears after a few minutes of run time.

Does the air change if your pump sits for hours or a day without running?

 

[zethacat]

No, I write poorly. Sorry. The air in the basket remains when I bleed the filter. Bleeding the filter only removes the air in the filter. Turning my pump on HI does, however, clear the air in the basket lid.

OK. So you are just getting air in the basket, not the filter. If the PSI does not change then there is no need to bleed.

 

[robdac]

Update. So tonight I had the Jandy valve turned towards spa to bypass the three Praher ball valves. I ran it like this with the pump on low for 3+ hours. There was no air in the filter at all which is a first. It appears that the problem is likely on the pool side of the Jandy valve. I expect one of the Praher ball valves has a bad O ring. It's all assembled so tightly I don't think I can flex the pipes enough to get to the O rings.

 

[robdac]

OK. So you are just getting air in the basket, not the filter. If the PSI does not change then there is no need to bleed.

I'm getting air in the basket and the filter. Much more air accumulates in the filter than the basket. Sometimes it takes 5-10 seconds to bleed the air out of the filter.

 

[robdac]

There is a good chance that the pump just can't keep up with the flow when running on low.

John,
Can you expand on this a bit for me please? I still haven't found where the air is coming from when the pump runs on low and want to consider this possibility before getting out my saw. Thank you for your advice.

 

[Geelow]

Leak in the suction side of the plumbing ?

 

[JohnT]

John,
Can you expand on this a bit for me please? I still haven't found where the air is coming from when the pump runs on low and want to consider this possibility before getting out my saw. Thank you for your advice.

On systems which have very little restriction on the discharge side of the pump, you sometimes see the pump unable to keep the basket full. How much increase in pressure can you get by closing valves in the discharge side?

 

[robdac]

On systems which have very little restriction on the discharge side of the pump, you sometimes see the pump unable to keep the basket full. How much increase in pressure can you get by closing valves in the discharge side?

Thanks for the clarification. I was only able to get a few psi pressure rise by closing the valves on the discharge side. One 2" pipe (going to the spa) has no shutoff, just a pressure restrictor.

On a good note, I did manage to locate what I now believe is the source of the air leaking into the system. You can hear air and see bubbles entering the pump basket when the ball valve from the pool cleaner line is placed in a certain position. I found it by luck not skill because the valve only makes noise when the pool pump is on high. I really appreciate the advice from everyone who contributed to this thread.