Advice needed:multiport main valve leaking on "waste" setting only

quentin_1 · Jun 19, 2016

Good morning and happy Father's Day to all the dads out there!

I have the Pentair FNS plus filter - it has been working fine. It is about 6 years old, I'd say. While it's been working fine, I've noticed the following issue - when I wanted to drain a little water and switched to the "waste" setting in the multiport main valve, there is very noticeable dripping. However, when I switch to "filter" or "backwash", everything seems fine.

Should I be worried and should I try to have this addressed as soon as possible? Could it be a cause for me losing pool water, too? I think I might have lost a little bit of water. I assume this is an easy fix, or do I have to replace the whole multiport main valve?

Thanks for your advice and help!

YippeeSkippy · Jun 20, 2016

No you don't have to replace the entire multiport valve. Your valve has a spider gasket inside it that might be slightly torn or damaged and can easily be replaced.

You can see a pic of a spider gasket here: Pool School - Visual Encyclopedia of Pool Equipment

How to change it- How to: Replace a Spider Gasket on a Multiport Valve - YouTube

quentin_1 · Jun 21, 2016

Thanks very much, I will try this. Rgds.

quentin_1 · Jul 1, 2016

Hello, a quick update : I finally replaced the gasket! Took longer as I didn't want to pay $35 for it at the pool store; it cost me $12.99 online.

The removal was a bit tough - had to scoop out the old one, literally. I cleaned and dried everything, as instructed. I did not apply any glue, as recommended here by most people. I did apply proper lube and didn't overdo it.

That said, I am concerned that I didn't apply any glue - why? Because the gasket I removed was glued! So shouldn't have I used the glue too?

Anyways, I hope all works out. I did not test if I still have the leak on the waste setting - will do that tomorrow.

Thanks for the advice folks.

PS
I saved $180 bucks by doing this myself (assuming half hour of labor)

YippeeSkippy · Jul 1, 2016

:::keeping fingers crossed for you:::

quentin_1 · May 21, 2017

Folks, hello!
My saga with leaking multiport valve continues, unfortunately! On "filter" setting, the water was leaking out the waste line at quite a quick clip. I had to refill the water as the level was close to below skimmer.

I can attempt to replace the gasket again, of course. However, my pool guy that I use tells me that at some point I need to replace the whole valve as changing the gasket isn't going to fix it. Does that sound believable to you pool pro's?
Does the multiport valve need to be replaced? When does it have to be replaced?

Thanks!

Scoop · May 21, 2017

This thread may help identify your Multiport Valve issue.

If your Multiport Valve is similar to mine, you may have a weak Spring or defective sealing surface on the Diffuser.

You may want to consider buying a spare Top Assembly for the valve. First, I'd obtain, if possible, your valve part number and manufacturer information so that you can order the correct parts for repair.

This thread may help regarding some questions about Multiport Valve parts replacement.