Multi-port Valve Issue?


LifeTime Supporter
Jul 1, 2009
Long Island, NY
I've been following the TFP method for the last 11+ years and have always opened early to a dirty (but clear) pool. This year, I opened late to a green monster that looked like a giant lime jello shot! One week later following the usual TFP methods, I was back to very clear water but with a high daily FC usage. I have noticed in prior years that I have had a high FC usage until I break down the filter and clean the grids after the initial opening. I assumed that the high FC usage was due to all of the organics that got cleaned out being trapped in the filter.

This year, I have seen small piles of off-white junk on the pool bottom that I thought was dead algae or tree pollen (which happens to be really high right now). I started thinking that maybe what I'm seeing on the pool bottom is filter media (I use cellulose) returning from the filter. When I broke down the filter last weekend to clean the grids, I inspected the internals and found no rips in the grids (1 years old), cracks in the header or any other visible problems. For good measure, I replaced the o-ring on the filter outlet riser pipe which was 11 years old but still in good shape.

I keep coming back to a possible problem with the spider gasket in the multi-port valve which is original and now over 11+ years old. From what I've read, when spider gaskets fail, the typical sign is water leaking from the waste port. In my case, there is no water leaking from the waste port when the multi-port valve is in the "filter" position. Do these gaskets ever fail where either filter media or unfiltered water is returned back to the pool?

I purchased a new spider gasket and the Loctite 406 glue that is recommended by the manufacturer. Do you think that replacing the spider gasket is the cause of the problem? I hesitate replacing the spider gasket this weekend because there is rain in the forecast for the next three days and I may have to lower the water level. I also need to keep the pump going to feed the chlorine monster.

Sorry for the long-winded post. Thanks in advance for your help.


Mod Squad
TFP Expert
LifeTime Supporter
Apr 17, 2010
East Texas
It's dadgum near impossible to replace just the spider gasket if the one in there now was glued in at the factory. Been there done that this spring. I had to replace the plastic top/ housing with another one glued in. Maybe you'll get lucky and yours won't be


LifeTime Supporter
Jul 1, 2009
Long Island, NY
Yesterday, I removed the multi-port valve and disassembled it to check the spider gasket. The spider gasket was flattened out and looked worn but there were no visible tears or missing pieces. Removing the old spider gasket was definitely a PIA and took a good 45 minutes using a small screwdriver. I also took apart the key assembly and replaced/lubed the shaft o-rings and cleaned all other parts. I followed the manufacturers instructions and glued the new one in, re-assembled the valve and let it cure overnight. As I re-installed the valve today, I noticed that the handle had more play in it than it used to. I took great care in re-assembling it in the exact order and that no parts were left out. The spring that puts tension on the handle was in good shape with only a bit of rust on one end. After starting the pump, I noticed an occasional dribble of water every so often coming out of the waste port. Not a lot of water but it never leaked in the past.

I guess I'll take the key assembly off tomorrow and see if the spider gasket is no longer seated correctly. I'm starting to wonder if compressing the spring to remove the handle pin has permanently compressed it and that is why the handle now has some play in it. This could also be the cause of the diverter not pushing down hard enough against the spider gasket thereby causing the minor leak to the waste port. Am I on to something? Could a spring replacement solve the problem?


Well-known member
Mar 29, 2020
Wilkes-Barre Pa
When I was inspecting my MPV I found worn areas. I purchased a spider gasket
and installed it. Then I had a minor leak (a couple drops) from my waste pipe.
I opened the MPV and found that the spider gasket had shifted. After that I replaced
the entire MPV. Fearing a failure was enough to just replace it.
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