Multiport Valve Leaking at the seam

[JohnT]

When we had the big rains last week, I went out and drained 4 or 5 inches of water out of my pool by backwashing a while and pumping the rest to waste. When I was finished, I set the valve back to filter, and water began leaking from the seam in the multiport. Here's a link to a drawing of the valve. http://www.poolcenter.com/parts_valves_ ... 12-147.htm The water was leaking from between parts 8 and 12, which are sealed with an O-ring, item 10.

I disassembled the valve and cleaned everything. I didn't see any sign of a problem. I reassembled the valve, making sure to evenly tighten all the bolts, but it still leaked. Filter pressures were exactly what they always are, and flow to the pool is excellent and just like it's always been. The leaking occurs at all multiport settings. The leak is mostly on the front of the valve, but it leaks most of the way around.

I ordered the gasket and plug assembly, item 7, and the O-ring, item 10, and installed them tonight with only a little improvement. I have the bolts tightened as much as I'm comfortable tightening them, which is tighter than they were originally.


I'm stumped. Anybody have any suggestions?

 

[waste]

John, welcome to TFP!! :lol:

I gotta say this is a mystery :? As long as the o- ring # 10 wasn't pinched, and parts 8 and 12 were clean and in good shape, the only other thing would be having the bolts tight enough. However, you know what you're doing and I trust that you properly checked all these and therefore, they aren't the issue. The other puzzling thing is that it happened after a heavy rain...

I'll let this perc a little in the brainpan, but I'm really hoping someone else can proffer a possible cause and solution :|

 

[JohnT]

I really couldn't see that O-ring failing unless it was during a disassembly/reassembly since it isn't used on moving parts. The pump loses prime pretty quickly when it's off, and it sounds like the air is coming into the system at the multiport. When I restart the pump, it reprimes itself after 45 seconds or so. The multiport is in good shape as far as I can see. I looked it over for a crack that might have caused it to not seat well and didn't find anything, but that's quickly becoming the only explanation I can see explaining what's going on.

Since that is where the pressure gauge measures, I can't imagine that the pressure is too high on the O-ring.

 

[JohnT]

Laid awake half the night trying to figure this thing out and I still don't know what to try next. On recirculate, the filter pressure is only 10psi and it leaks just as badly there as it does when it's on filter with the solar on with the pressure at 20psi.

I brought one of the bolts and nuts to work with me and used a torque wrench to compare the recommended 55inch-pounds with how I was tightening them. I think they were tighter than recommended on my last install, but I took care to tighten them all evenly and gradually.

 

[spishex]

Try starting with the bolts as loose as possible while still holding the valve on securely. I've met a few pieces of equipment in the past, especially MPVs, that would not seal unless you started with as little pressure on the o-ring as possible and then tightened a bit with the pump on.

And if that doesn't work you can always go with the last resort.

 

[JohnT]

Try starting with the bolts as loose as possible while still holding the valve on securely. I've met a few pieces of equipment in the past, especially MPVs, that would not seal unless you started with as little pressure on the o-ring as possible and then tightened a bit with the pump on.

And if that doesn't work you can always go with the last resort.

Looser bolts will be my first try when I get home. I've seen the same thing on some sealing plates at work.

The silicon idea has been playing around in my head for a while. It's good to know it's not completely insane (or if it is, I'm not the only one who is insane ). My plan was to apply a bead and partially snug the bolts down to let the sealant cure, then tighten them the rest of the way after the sealant cures so it won't squeeze it all out.

 

[duraleigh]

Hey, John,

I have a different MPV so I'm just stabbing in the dark...........could the leak be originating somewhere else on the valve and only appearing to come from that spot?

It sure sounds like you have done all the right things....could it be tricking you?

 

[JohnT]

Hey, John,

I have a different MPV so I'm just stabbing in the dark...........could the leak be originating somewhere else on the valve and only appearing to come from that spot?

It sure sounds like you have done all the right things....could it be tricking you?

Well, it could be fooling me, but the way it's constructed it seems fairly straightforward where the leak is. Before I changed the O-ring, it was actually spraying at times. I've dried the valve, and the water just begins weeping out of the seam as the pump begins to prime. The base is a little larger than the top, so the water first appears on top of the base.

I neglected to mention that I've also verified there is no air in the filter. The fact that it's leaking air too when it's not under pressure is making me consider some kind of structural failure of the valve. The thought occurred to me this morning that there could be a crack in the groove that holds the O-ring, allowing water and air to bypass it. Being black plastic, it can be pretty hard to see into the groove.

 

[dmanb2b]

John, welcome to TFP!! :lol:

too funny,,,good luck with solving your problem John

 

[JohnT]

Well, I have it working. I took it apart again and cleaned the groove with alcohol and a small pad. It was picking up something black. Cleaned it until the pads stayed clean. Put a heavy coat of lube on the O-ring, which I don't like to do as it can catch debris. So far so good, but I don't like it. Shouldn't be that hard to get a seal, and I have no clue what caused the failure to start with.

 

[X-PertPool]

A pine needle on the valve seat gasket can cause you to lose water out your. Backwash. So you did good by cleaning everything so well. I always lube the o-rings as it acts to protect the gaskets from corrosion. That black stuff you found was rubber from a damaged gasket.