Help Please: Multi-Port woes

[Chappie]

The spider gasket in my multi-port was bad and causing a steady trickle leak out of the backwash exit pipe. Yesterday, I replaced it, and everything was working great, leak solved.

Today I rotated the lever to do a backwash. After the backwash and rinse, I put it back to “filter” and it was making a non-normal sound once I turned it back on. Additionally, water filled up the backwash port, and of course, there was a steady rush of water out of the backwash pipe.

I have removed and replaced the multi-port valve several times. To my eye, the gasket seems fine. All of the functions seem to work as normal, so I’m not doing a rinse when it’s set to filter or such.
How do I fix this?

 

[ajw22]

Did you open up the MPV and examine the condition of the gasket?

 

[Texas Splash]

Might help to know what make/model MPV you have. When was the last time the handle stem spring and washer(s) were replaced? Not enough spring tension may be to blame.

 

[Chappie]

Might help to know what make/model MPV you have. When was the last time the handle stem spring and washer(s) were replaced? Not enough spring tension may be to blame.

It appears to be a Pentair 262506. I had to look up different models and compare to mine, but I think that's it. It has been quite some time since the handle spring was replaced. I'll order one and see if that helps.