Hayward filter head works in all settings but “filter”…gasket or replace head.

[Canned Heat]

Never have had this happen before. Enabled my water fall feature with a ballcock valve with system running and water entering/exiting as normal (done this a couple dozen times or more)…and filter system shook and rattled. Shut down system asap, checked for blockage and flow. Opened to waste, and powered on to waste - fine. Run it on rinse - fine. Turn valve back to filter setting and no water moves thru pump or out of the eyeball. Stumped. Gasket? Blockage in sand filter somehow? At a loss and of course supposed to go out of town in a day for weekend. Thanks in advance super friends.

 

[Texas Splash]

Perhaps the gasket or diverter keyway assembly simply failed. There's also a very stiff spring tucked under the lip along the shaft of the handle, and perhaps it's become weak. You can replace each part, but sometimes it's more cost effective to just replace then entire head unit.

 

[Canned Heat]

Thanks....that was my initial thought or somehow a blockage - that I couldn't wrap my head around.

I got up at 4:30 this morning and I tried running on "recirculate" this morning and got the same issue. I then tore it all apart, working backwards from the jet. Friend of mine mentioned blockage maybe at eyeball...nope. Took the head off the valve and the spider gasket and valve components appear like new (new gasket last year).

It looks to be a faulty check valve or the inline chlorinator (which I think is the culprit) between the sand filter and that diverter. Removed those links in the chain and we now have perfect flow and performance/pressure. I just need to piece back together this afternoon, with some new PVC patch work and we'll be up and running before long. Thanks a bunch for the insight. We have roughly a month tops left of pool time here in WI, so I will make due without the ILC for the remainder of the year and replace in spring or at shutdown.

 

[Texas Splash]

Great to hear you found the culprit.