Multiport valves can leak both internally and externally.  If water appears under the filter, use a flashlight to inspect underneath.  If a leak is detected where the plumbing enters the valve openings, you can repair that without disassembling the entire filter.  If the leak appears to be at the joint of the valve and filter tank, or if the DE or dirt is bypassing the normal flow and getting back into the pool, you will need to tear down the filter and valve.


How to tear down the multiport valve:

  1. Cut the plumbing and electricity to isolate the filter. HOW?
  2. Reach inside the bottom of the filter and remove the bolts that hold the compression right with a nut driver.  This ring holds the valve in place as well so the valve will now fall away from the filter tank.
  3. You now have the valve body with the rotor inside.  Remove the handle on the underside of the valve by removing the bolt assembly that holds it on the rotor shaft and slide it off the shaft.  Pull the rotor out of the body.  Bronze rotors are very hard to remove and you might have to take the valve to Memphis Pool.
  4. Pull the old rotor seal gasket from the rotor with needle nose pliers.  Clean the rotor and inside valve body.  Put a new gasket on the rotor, being careful not to over stretch the new gasket.
  5. Lube the gasket with silicone lube and replace it in the valve body.  On bronze rotors, each port has an o-ring instead of one body gasket seal.  Before reassembling the filter, replace the o-ring that sits between the tank and valve and the o-ring that seals the shaft as it passes through the valve body to the handle.  Also, replace the o-ring on the neck of the rotor.  The grid manifold sits on this neck and the o-ring seals that joint, so to prevent dirt from bypassing the correct direction of flow, and lube all o-rings with silicone lube.
  6. Reassemble the valve and tank the way you took it apart.  Be sure the tank itself is clean and that the opening in the bottom shows no rust or cracks.  If it does, you should clean it thoroughly and have the cracks welded. 
  7. Replumb and restart the filter.

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