Equipment Maintenance – Multiport Valves

When your pool sand filter’s multiport valve starts leaking or the handle starts losing tension (or even becoming too hard to turn) then it’s time for some maintenance. Don’t worry though, multiport maintenance is pretty simple and it can be done with a minimum amount of tools and a bit of elbow grease.

Problem: Leaky Multiport Valve

The solution to multiport valve leaks depend on where the leak exactly is located so we’re going to go over the possible leak locations so you can zero-in on the cause and fix it without replacing the whole multiport, which can cost almost half the price of a new pool sand filter.

Leaking underneath the pressure gauge

This is the most common type of leak on the multiport valve. Water leaking out from around your pressure gauge.

  • Teflon Tape Problems – Either there is too much or too little (or none at all) Teflon tape on the pressure gauge’s attachment. The fix for this is simple, either add or remove Teflon tape depending on the situation. The perfect amount of tape is around 1 or 2 layers, depending on the snugness of the fit of your pressure gauge. *note: when adding/removing Teflon tape from your pressure gauge, or any other fitting that requires tape, completely strip off the old tape and reapply new tape.
  • Stripped threads – If you come across a stripped thread then no amount of Teflon tape can seal up the leak (and you shouldn’t try to seal it up with tape). The best solution would be to head on down to your local handyman shop and pick up a thread repair insert to give you a new set of threads for your pressure gauge.
  • Cracking around the threads – This is usually caused by using too much Teflon tape on your pressure gauge attachment, creating a seam or a crack around the thread and causing water to leak out. The fix for this is simple. First, put in maybe 5-6 layers of Teflon tape around your pressure gauge attachment and then screw it in. The thick layer of tape should open up the crack even more. With the crack opened up, put in some epoxy or some Aussie Gold Aqua Fix-it in the crack, then remove the pressure gauge so that the crack closes in on itself. Wipe off the surface to remove excess sealant and allow at least 30 minutes to dry out and cure. Remember to remove the excess Teflon tape before reattaching the pressure gauge.

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  • The water is coming FROM the pressure gauge – Well, this problem has a very simple fix. Replace the filter gauge completely.

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Leaking around the cover

If you have a leak around the cover, the first thing you should check is the pressure levels. If they’re way above normal then you may just need to backwash your filter and check your return lines for any blockage. If the pressure is normal or low then the probably culprit is a damaged or dried out assembly O-ring. Simply unscrew the entire multiport assembly from where it attaches to your sand filter and check the O-ring for damage. If the O-ring is intact, wipe it clean with a damp rag and reapply some silicone lubricant and re-seat it, making sure to clear the surfaces of any debris that may be causing the leak.

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If the O-ring is cracked or broken then don’t worry, Mr Pool Man has a large range of O-rings available online so you can order a replacement and take care of that leak once and for all. Don’t forget to apply some silicone lubricant to your new O-ring as well to prevent drying out and cracking!

Leaking water under and around the handle

Usually the cause for this is the small O-rings on your multiport valve rotor getting unseated or having debris get stuck there. In that case then the fix is quite simple, simply clean and reseat the O-rings (don’t forget to apply the silicone lubricant) and your leaking problems should be gone. If the O-rings are dried up or damaged then you may have to take them out and bring them to your local handyman or pool store to see if they have them in stock. Don’t worry, these are small generic O-rings that you can get for a couple of bucks at a well-stocked handyman or pool store.

If for some reason you discover that your valve rotor is cracked or damaged then you have a bigger problem on your hands. You can try to fix it with some aqua fix-it as a short-term fix, but we recommend replacing the valve rotor completely for a longer term solution.

Leaks where pipes are connected to the multiport valve

These leaks are usually caused by sagging pipes that put too much downward pressure on the fittings or on the valve body itself. If the cracks are small then you can patch it up with some Aqua-Fix it as described in the section above in repairing a cracked pressure gauge connection. Don’t forget to fix the cause of the problem as well (sagging pipes) to prevent any future cracking and leaking.

Problem: Water is leaking out of the waste line

This can be caused by two things, a broken spider gasket or a failure of the spring inside of your multiport assembly.

Changing the Spider Gasket

The spider pig... I mean spider gasket is one of the key components of your multiport valve that directs the flow of water and keeps it out of places where they shouldn’t be going. A broken spider valve means that not all of the water is going into your filter and may even be bypassing it completely. So if water is leaking out of your waste line even though you have it set on filter or recirculate then this is something that should be replaced as soon as possible. Here are the steps to replacing your spider gasket.

  • With the system off and depressurized, uscrew the valve cover from the valve body.
  • Remove the old spider gasket from the valve cover assembly.
  • In some setups, the spider gasket is glued on so you may have to use a small screwdriver or some other tool to scrape off the old glue/stuck bits of gasket
  • Once the old gasket is removed, clean the surfaces of the gasket groove, make sure there are no more debris left and that is completely dry.
  • Add some waterproof glue to the bottom of the spider gasket groove in a continuous line. Do not apply glue to the sides or it may overflow and be the cause of leaking in the future.
  • Insert your new spider gasket into the groove with the rounded bead side up, press and seat it properly and wipe out any glue that may have overflowed.
  • Reattach the valve cover to the body and turn the handle to the nearest available setting (rinse or filter) and then allow to rest for at least 24 hours for the glue to fully cure and for the spider gasket to be firmly seated.
  • Use normally after 24 hours.

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Note: Spider gaskets are brand-specific to your multiport and may not necessarily be the featured product displayed above. To find out the spider gasket needed for your multiport, click on the button below.

Changing the Valve Spring

The other reason for water leaking out of the waste line is a broken valve spring. A good sign of this is if your multiport handle feels “floppy” or loose. The spring provides tension to push down the valve rotor to effectively seal off the compartments of your multiport valve. While the springs are usually made from stainless steel, the constant movement, exposure to elements and pool chemicals will eventually cause the valve spring to fail. Good thing replacing it quite easy, simply open up your valve assembly and replace the old spring with a new one and you should be good to go.

Problem: My Multiport is old and about to explode!

You know what they say, time makes fools out of us all and this is true with multiport valves as well. If you encounter multiple issues with your multiport valve or if it has gone through multiple repairs over the years, it would be cheaper and easier to just replace the whole thing.

Do you have any questions about this topic or the featured products? No worries, we're here to help! Drop us a question down below and we'll get back to you ASAP.

Happy swimming :)

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Post author:

Tom Hintze

Head of eCommerce & Operations at Mr Pool Man,
Co-Founder at Water TechniX

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