Sta-Rite MPV leaking through backwash when on filter position

JohnGn

Gold Supporter
Sep 28, 2019
57
St. Louis, MO
Pool Size
19000
Surface
Vinyl
Chlorine
Liquid Chlorine
When the pump is running, I have a slow leak out the backwash pipe. I thought maybe I could just change out a black rubber spider gasket, but when I opened it up, I found a hardened white "gasket" embedded in the head of the valve, and a large still-flexible o-ring in the body. I can put some silicone lube on both parts and see if that helps, but the white gasket part looks worn.

The white gasket thing definitely looks like it needs to be replaced. I haven't seen anything online that looks like that. Do I need to replace the whole head portion?

It's an outdated model WC 112, either 147 or 148. It's a 2", so I suppose it's a 148.

Any suggestions?
 

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Probably answering my own question here, but I found this: Multiport Valve Plug and Cover Assembly for Sta-Rite 1-1/2" WC112 Series Valve - 77704-0104 - INYOPools.com

It's the whole top assembly including the white gasket part that I think needs to be replaced. I was hoping I could get by with just a cheap gasket, but if I need a new head, I'll spring for it.

Does anyone have any better ideas? Can the crusty white gasket part be chiseled out and replaced? Or is it just better to buy the new part?

Thanks.
 
Look here, particularly part #9. Should need the whole head, just the "plug and gasket assembly" and any other r-rings that may be bad...like the seals, #5, 10, 13 in the diagram: NOTE:this assumes you have the -148.

 
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Look here, particularly part #9. Should need the whole head, just the "plug and gasket assembly" and any other r-rings that may be bad...like the seals, #5, 10, 13 in the diagram: NOTE:this assumes you have the -148.

Thanks very much for that info. Yeah, I suppose I could try ordering each of those individual parts and hope I can put it all back together just right, but for not a whole lot more money I ended up buying the whole new head. In particular, I took a hard look down inside the head and there are a bunch of rusted parts, including the spring. And, the whole thing has been leaking out the top for a couple years, but not enough to worry about. This time, what caused me to notice the backwash leak was that I was running my pump 24/7 due to a SLAM and noticed I was losing about an inch of water every couple of hours. And when I peeked around where my backwash flows out onto the sidewalk beyond my property, it was wet. So...conclusion drawn, and new head on its way. Thanks, again!