The pressure relief valve on my DE filter is leaking. It appears to leak between the 'hockey puck' top and the main body of the valve. I tried to outline the area where the water appears. (Yes, I know the manual pressure relief screw-in thingy is leaking in this picture; I didn't tighten it enough after backwashing this afternoon).

I have used O-ring lube on the rings connecting the valve to the top of the filter, the big ring in the center area and the small ring around the manual relief knob. All of the rings look good to the eye.

Is this the filter Hayward has orphaned? Is there another place I should be looking for a leak? If the valve is shot is there any alternative to replacing the whole filter? Any other ideas?

Looks like you got one of Hayward's failed experiments from the early 00's, to whit, the automatic air bleed.

Pull the top off and rinse the housing around the float ball - probably a bunch of DE is in there, then make sure the sock is on correctly. Most of the time, this takes care of the problem. If it doesn't, order a DEX 2400 MAR (MAR stands for 'manual air relief') - hockey puck.

Thanks for the fast response.

That is the alleged 'automatic' air relief valve, DEX2420AR. I'll order a new manual air relief valve and be done with it. It appears I should also order a spare main o-ring or two. Are they still available or am I chasing the Holy Grail? This is becoming the proverbial money pit!

The replacement air valve arrived this week. Yesterday I changed the old, somewhat leaking, automatic air relief valve to the new manual air relief valve. I had to use the old O-ring; for some reason the one provided with the replacement valve was a tad too large - wouldn't fit into the recess atop the filter.

All is well in the world - no more leak from the valve area. Thanks, Waste, for your input.

A side note: After backwashing and replacing the valve I had a problem with the skimmer sucking air and bubbles shooting from the return lines. I just couldn't get the air out of the system. I went back to the auto valve and had the same issue. Thoroughly confused, I tried everything I could think of to no avail. Put the new valve back on - obviously not the problem. After fighting it for an hour I found the flapper door (weir?) on the skimmer was somehow stuck open. A gentle nudge and everything returned to normal. A major DUH! moment!

Great!