Sight glass still leaking in filter mode -- but spider gasket is brand new

[JaySee]

Hi everyone,
Long story short, I have a Hayward SP711 sand filter, and in filter mode the sight glass was filling up with water with a constand drip/leak.

Opened up the filter, sure enough the spider gasket was torn. Replaced it, and the leak stopped.

One week later after doing a backwash, the leak is back though not as extreme. I opened up the filter and the spider gasket is in perfect condition, perfectly seated, as far as I can tell. Lubed it up again and closed it up, but it keeps dripping from the sight glass in filter mode.

Weird thing is that it's intermittent. Sometimes it leaks a little bit when I first turn on the filter and then stops shortly after. Other times it leaks for the entire length of time I have my filter on. I put a dry towel under the sight glass to check-- it can range from being bone dry to being sopping wet.

Any ideas why is this happening?

An extra twist-- the sight glass was installed so tightly I'm afraid to remove it with a tool and break it by accident. Clearly the sight glass shouldn't be leaking at all, but the fact that it's leaking in filter mode has me perplexed.

Thanks!

 

[JaySee]

I should add-- after replacing the spider gasket I did a week long SLAM with the filter running 24/7 without any leak. The leak started again after doing backwash/rinse after the SLAM was complete. Is a "clean" filter more prone to leaking?

Thanks!

 

[Getitrite]

I should add-- after replacing the spider gasket I did a week long SLAM with the filter running 24/7 without any leak. The leak started again after doing backwash/rinse after the SLAM was complete. Is a "clean" filter more prone to leaking?

Thanks!

JaySee -
I have DE Filter, but you may have the situation I ran across last year (never got around to posting...). You may want to check the Sight Glass Gasket. Mine was "off center", as indicated by the tell-tell contact mark around 2/3 rds of the gasket by the sight glass. I suspect that bit of "non-contact" caused my leak. (I used a thin garden hose gasket as my "temp" repair, which ended the leak. Super Lubed and didn't crank on it when tightening.