Why Is My Multiport Valve Leaking?

November 20, 2014

3 Minute Read

Multiport valves are the main water route interchange for your pool water. If the water needs to be forwarded, reversed or drained out, it will need to be done through this valve. The routing system inside a multiport valve is essentially water’s equivalent to chutes and ladders.

These valves have as many as seven “positions” but for the most part the average pool owner will only use a handful of these. Here is a list and explanation of the most often used positions so we have a solid footing moving forward:

Filter – The standard operation mode; the water is cycled from the pump through the filter media and back to the pool.
Backwash – This selection is the cleaning cycle. The flow of the water is brought in from the pump then routed to enter the filter reverse to the normal direction. This effectively begins to loosen and eventually eject dirt through the waste port.
Rinse – Rinse returns the normal flow of water through the filter but it maintains the exit flow routed to the waste port. After a backwash some particles may still be left in the pipes so to avoid that dirt being ushered to the pool, we need to rinse.

The Spider Gasket

If the valve is the highway interchange of your water then the spider gasket would be the guard rail. These gasket spokes act as dividers to ensure the path of the water stays true. If your multiport valve has a drip coming from the waste port line, most pool technicians will jump for the spider gasket.

The spider gasket is located either on the diverter pinwheel or the base of the valve the diverter faces. When we select a function on a multiport valve and release the handle, we drop the diverter onto the spider gasket. If the gasket has become worn and warped then the water will seep through the seam and end up in the waste.

The Fix: The solution is pretty simple, replace the gasket. Some gasket replacements are simple, remove the valve cover and old gasket, then lube in a new one. Other gaskets are glued into the diverter which requires a few extra steps. If you want a step by step guide on the different ways to replace a spider gasket read this: How to Replace a Spider Gasket on a Multiport Valve

The Diverter Spring

That tension we feel when spinning the selector handle is created by the diverter spring. Besides making it hard to spin the handle, the spring serves the purpose of locking

the diverter against the spider gasket. If the spring in your valve is worn, it may be causing a seam between the diverter and gasket which shows itself in the form of a leak out the waste port.

The Fix: Replace spring, which to be honest, is not fun at all. The spring is sandwiched on the diverter assembly which means it must be disassembled and assembled again. The hard part is getting the spring depressed enough to secure the handle pivot rod. If you are feeling brave and want to attempt a spring replacement, please follow our guide: How To Replace a Pool Multiport Valve Spring

Valve Cover

The valve cover o-ring is found in the seam between the valve cover and main housing. If water is found leaking from this seam then this gasket would be your culprit. To access the gasket we would simply remove the 6 – 8 screws on the valve cover to remove it, peel out the o-ring, clean the groove, lube the new o-ring and re-attach screws.

The Fix: Read an inch above this line.

Valve to Filter Connection

Whether the valve is a top mount or a sidemount, it has to connect to the filter somehow. At that joint connection there is a gasket holding on for dear life. Because of the high flow at these connections, a blowout is somewhat common and easy to spot.

The Fix: Remove the valve from the filter and replace gaskets. Hopefully, the valve is piped in with unions so its removal is not a pain in the neck. Once the valve is off, find the gasket and apply a freshly lubed replacement.

Thanks for skimming through our pool musings. If you have any further questions about pools, valves or otherwise, feel free to give us a call at 877-372-6038.

Matthew Simmons Technical Writer & Pool Product Expert

Swimming pool expert at InyoPools and host of Poolside Chat, brings over a decade of experience in the pool industry.

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119 responses to “Why Is My Multiport Valve Leaking?”

Melanie

May 23, 2018

I have water coming out the backwash port while on filter and when on backwash the jet is blowing in the pool. We have replaced the spider gasket and looked at the lateral assembly nothing wrong there and of course we chamged out the sand.

Reply
1. Matthew Simmons
  
  May 24, 2018
  
  Is the valve handle jiggly? Like the article mentions, if the spring is old it will begin to give. The loose spring allows the diverter to shift up pushing water out where it shouldn’t be, like your backwash port.
  
  Reply
Okhouy

September 24, 2017

I am adding water to my pool 2 times a week. No visible leaks around pool. Could the multi port valve (Jandy) with sand filter be leaking internally and how can I verify that?

Reply
1. Matthew Simmons
  
  September 25, 2017
  
  Check your waste port. If the valve is leaking internally the only place the water would be able to escape is through the waste port.
  
  Reply
  1. Anonymous
    
    September 25, 2017
    
    Any quick way to check that without opening the valve?
    
    Reply
    1. Matthew Simmons
      
      September 25, 2017
      
      Yes, check the waste port.
      
      Reply
marvin m

August 24, 2017

My variflow is leaking from the bottom pipe that commects to the filter tank. Is there a gasket where that pipe goes into the variflow housing? Its leaking from the section that goes into the variflow housing.

Reply
1. Matthew Simmons
  
  August 28, 2017
  
  What is the model number of your filter and valve? Hayward makes several with the name Vari-Flow, side mount and top mount versions.
  
  Reply
Stephanie

August 13, 2017

Please help. I have a few questions. What if we don’t rinse after backwash? Could that be the reason water is pouring out the drain while on filter? Also, does it matter which direction (clockwise , counterclockwise) I turn the latch to switch modes?

Reply
1. Stephanie
  
  August 13, 2017
  
  Also, does it matter the precise level of water in the pool? If it’s too full will it drain on filter mode?
  
  Reply
  1. Matthew Simmons
    
    August 14, 2017
    
    Question, why wouldn’t you rinse when you backwash your filter? Also, have you opened the valve to check the spider gasket or diverter spring as the article suggests? If not, I would start there.
    
    Yes, it does matter how the handle is turned. You should only turn it one way if you take turns going clockwise and counterclockwise there is a higher chance of the gasket getting stretched or pulled out of place.
    
    Reply
Jason

August 2, 2017

I have an Sand Dollar SD-40 with 1.5″ 6 position multi port valve. Just replaced the diverter with gasket and the spring on the diverter stem. Reason for replacement was water was leaking out the backwash value about as fast as it was going in the return. After replacement of these part problem remains. If I select backwash nothing comes out the backwash port. If I select filter water comes out backwash and return. If I select rinse water comes out only the return to the pool. Did I put something in backward have something else damaged?

Reply
1. Matthew Simmons
  
  August 3, 2017
  
  The handle and diverter may not be properly aligned. If you remove the handle assembly on the valve is the hole on the diverter opposite the handle, as pictured?
  
  Reply
  1. nairu rathod
    
    January 20, 2018
    
    sir can i have overall details of mpv’s and auto mpv’s
    
    Reply
    1. Matthew Simmons
      
      January 23, 2018
      
      Can you be more specific? That is a very wide net you are casting.
      
      Reply
Sarah

July 22, 2017

Hi, we have a strange water leak in our pool. It leaks only occasionaly, just up to the bottom of the skimmer level. Then for weeks it’s ok, then we lose water again! we’ve checked for wet areas around skimmer etc and all seems ok. i do know our Multiport valve has gone, the heavy spring doesnt work. When we move it we make sure it’s back in it’s proper place. There are no leaks within the pump room coming from the Multiport Valve so i guess it was ok. We’ve checked the main drain looking for any water coming out but cannot see any leaks in there either. Can there be underground leaks or leaks we cannot see if the Multiport Valve is causing this loss?

Reply
1. Matthew Simmons
  
  August 2, 2017
  
  Yes, there can be leaks from the leaks in the pool basin, but it would be odd for that type of leak to go away for a couples weeks then come back. The multiport valve could also be the issue, especially if your multiport valve spring is shot. A bad spring can cause water to flow through the backwash port. have you checked the area to where the backwash pipe drain to determine if the area appears wet when it shouldn’t be?
  
  Reply
bill

July 17, 2017

if your multiport valve is leaking would this cause you to get low return pressure

Reply
1. Matthew Simmons
  
  July 17, 2017
  
  Probably not, but it is a sign of a bad gasket or cracked plastic piece.
  
  Here is a guide that might help you: How to Correct Low Water Pressure in Your Pool System
  
  Reply
Jenn

July 16, 2017

My multiport valve is leaking under the handle (hayward), could it be the spring or the spider gasket? And could that leak be the reason why my pentair Intellichlor generator has a solid red flow light and salt water low light blinking red? I also hear bubbles coming from one of the return lines.Both returns seem to be full power (albeit the occasional bubbles). I already cleaned the Intellichlor cell with the acid, but there wasn’t any calcium in there anyway, this is it’s 2nd summer. After putting it back together, the flow light was green for about 10 seconds before going back to red.

Reply
1. Matthew Simmons
  
  July 17, 2017
  
  It would have to be a heavy flowing leak to compromise the flow switch in a cell. But your system sounds like it has two separate problems besides the cell: an air leak and leaking valve.
  
  The bubbles coming from your return are likely from an air leak. Here is a guide that can help you in find the source: How to Correct Low Water Pressure in Your Pool System.
  
  The leak from the top of the multiport valve could be a bad diverter stem o-ring or broken washer. You will have to open up the valve to take a look. I am not sure what which valve you have but this exploded part view of a valve may help. Key 7,8,and 9 are the washer, spring, and stem o-ring respectively.
  
  Reply
2. Matthew Simmons
  
  July 18, 2017
  
  The two major sections of the article mention the spring and spider gasket as possible causes for leaks.
  
  Reply
Gareth

July 9, 2017

Had a leak for while coming from the handle of the MPV. So took it apart, cleaned it, and reassembled. Smooth turning of the handle but leak probably a little worse. Plastic washer looked a little worn and was quite a gap from the plastic washer under the handle from touching the stem. So took back chance and bought a washer from a Hayward MPV as mine is no longer listed online or sold anywhere as it’s so old. Anyway, I reinstalled but it didn’t fix the leak from under the handle. So reinstalled and flipped the original plastic washer, still no joy. So I repeated procedure and added vaseline to plastic washer and metal washers either side of the spring. Still leaking. Can’t see any cracks, spring has lots of tension in it. Can’t see what the problem is. Please help?

Also does it matter how tight I tighten the 6 screws? Will it make a difference?

Just to confirm I have no leak from the sides of the MPV. The metal washers either side of the spring are not bent and look true. They are identical when paired together. What’s my next step?

Reply
1. Matthew Simmons
  
  July 10, 2017
  
  What is the model number of your valve? I need to get an idea of what you are working with.
  
  As long as the screws/nuts aren’t juggling they should be tight enough to prevent leaks.
  
  Reply
  1. Gareth
    
    July 10, 2017
    
    Thanks for the reply. Where can I find a model number of the valve? The only markings or name is on the handle itself.
    
    Reply
    1. Matthew Simmons
      
      July 11, 2017
      
      The model number should be listed on or around the top sticker of the valve.
      
      Reply
Guy

July 7, 2017

I have a Pentair 261050 high flow valve that was sticking awfully on turning. It never actually leaked, but I always thought it not good that it make loud creaking noises when turning it. I figured maybe something inside just needed a lil lube. So I disassembled it (8 screws) and the washers look a little bent but otherwise everything looks fine. The spring has a lot of tension. No damage seen to gasket or diverter. So I cleaned everything and wiped the spring and washers with a paper towel that had a little wd40 on it and put everything back to gether. The valve now turns smooth as butter but there is a tiny leak under the handle. A little bit of water collects under there, not a huge leak. So I took everything apart again, and took the oring off the diverter (which wasn’t easy) and lubed it, and put everything back together again but it still leaks a little under the handle. I ordered a new oring and will see if that helps. Someone suggested it might be my spring but I don’t understand how. It has a lot of tension. The handle does jiggle but the handle screw is threaded. Considering the handle is simply used to lift the diverter I don’t think this is the cause of my problem. I ordered a new handle too anyway. I guess I’ll order a spring next, and washers next. I hope I don’t need a new valve. Your opinion?

Reply