Hayward filter air sound

[matt4x4]

It's an air trap, it's just not leaving, here's what I do with that problem, I unscrew the pressure guage very slowly while running the system, first, some air will come out, then water, once water comes out, tighten the pressure guage and all should be good.
If air comes back, you have a suction side leak (pre pump), if it's an AG pool, a suction side leak will not empty your pump (lose prime) due to it's location below the water line, however, the air it's sucking in will push to teh filter and through depending on how much collects.
A suction side leak is usually due to a couple of things:
1. water level too low, causing vortex in skimmer, vortex draws in air. simple fixes are top up pool or place large item like a stone in skimmer, this will break up the vortex.
2. Small leak on any fitting between skimmer and pump, because it's suction side, it will not show as a leak when pool is running since it's pulling in air instead of pushing out water, the way to find the leak is to shut off the system and wait for water to appear somewhere, can be hard to trace since it may be so small, water can't get out but air can get in.
Fix might include checking tightness on all clamps, sometimes 1/8 of a turn will do it.

[Poconos]

A couple things I found about this filter...same or similar to mine, an S-244T. If you do get air rattling around in the valve assembly it will persist if the flow isn't high enough to drive it out. This happens to me when I vacuum sometimes, and the vacuum hose restricts the flow on the suction side. Going back to full skimmer flow corrects the problem after a few minutes. Every time I vacuum I get air in the system because I don't fill the hose with water before hooking it to the skimmer. Too much bother. Next, whether it is by design or just the way it happened, the center pipe in the filter is a very loose fit to the mating pipe in the valve assembly. This center pipe is the water return from the laterals at the bottom of the filter. With the loose fit any air that gets into the top of the filter, above the sand, is at a slightly higher pressure than the water in the center pipe and the trapped air will leak past the sand, through this loose joint, and get purged from the system.
Al
Another thought...what pressure is this filter running at? Reason I ask is possibly your flow is being reduce by the eyeballs in the return jets or any other devices you have in the return path. I bored out my eyeballs to cut the flow resistance and up the flow a little. Not because of the air issue but just because I hate things that restrict flow.

[KirstenHW]

My Hayward EC-65 DE filter (no multiport) makes a rattling noise too. And it is worse when I vacuum. We had the 2 return lines and the wall vac line repaired, but it still does it. Another odd thing I noticed is that in past years the typical operating pressure of the filter was around 6-8. This year it hovers around 2. Any comments on this?

[matt4x4]

Yours sounds like you sucked in a pool toy, might want to open it up and look inside!

[KirstenHW]

Matt - are you referring to me? (Its hard to tell with the threads sometimes). I don't have kids, so no pool toys . . . I thought I'd try the pressure gauge trick mentioned above. The low pressure vs. last year is perplexing to me as well.