High pitched air sound coming from pool filter collar?

[ddivita]

I have a Pentair SD40 with a 1.5 HP Dynamo pump. Recently, I replaced the plumbing (not the pump to filter hose) and the filter sand. I did not purchase new O-Rings, because they looked OK. I did lube the rings.

There is definitely air getting into the system, but I cannot determine from where. It sounds like something rattling around in the filter valve when I first turn it on. After about an hour that sound goes away, but I hear a high pitched air sucking sound coming from near the collar of the valve. I tried the shaving creme, smoke, and soap suds tricks to find any air leaks, but none of those methods indicated a leak. The water flow going back into the pool drops after about an hour. If I backwash the system then move back to filter the pressure is good for about an hour. When I start to hear the high pitched noise I can put my hand in front of the pool port (coming from the filter into the pool) and the noise goes away.

Today, I purchased new o-rings and the pump to filter hose to be safe.

Could it be failing o-rings or could this be a bigger problem?I'm not sure what else to try.

 

[ajw22]

Welcome to TFP.

Please create your signature with details of your pool and equipment. Knowing your complete system lets us give you better advice.

Post some pics of your filter and the plumbing around it.

When I start to hear the high pitched noise I can put my hand in front of the pool port (coming from the filter into the pool) and the noise goes away.

You mean the water return pipe in the pool?

 

[ddivita]

I updated my signature and will take some photos / video this week. I think air is getting into the pump, but I'm not 100% sure where. I can see bubbles through the lid. The air sounds like it is being forced through the collar of the filter, but my pressure gauge still reads 20 PSI. I re-tightened all the fittings and made sure the o-rings were all seated properly. I don't hear the high pitched nose much anymore, just the crackling of air inside the filter.

 

[ddivita]

Here's a quick video of what is going on:

 

[Brett S]

If you can see bubbles through the lid of the pump basket then that means that air is coming in on the suction side. There would be no way for air to come in on the pressure side of the pump and then go backwards though the pump into the basket. Additionally any leaks on the pressure side would likely have water coming out, not air going in.

Definitely focus your efforts on trying to find a leak on the suction side, possibly using a hose to flood each joint one at a time to see if the bubbles disappear. If there is water on the outside of the leaking joint then it will suck in the water instead of air. Remember to check the pump basket lid and drain as well.

 

[ddivita]

Turn out the sand I used was causing my issues. I purchased Quickrete pool sand on a recommendation from a pool maintenance person in my area. It's too fine and does not work will with my filter. Lesson learned.