MPV Valves - Further Reading

Multi-Port Valves

MPV (Multi-Port Valves) are the big valves found on DE and sand filters. They do a number of functions as described below. Not all MPVs have all the modes listed.

An MPV valve is specific to a model filter and are usually not interchangeable.

MPVs on DE filters are mounted on the side. MPVs on sand filters may be mounted on the top or the side. Note that side mounted MPVs on DE and sand filter have the in and out pipes reversed - top in for sand filters and bottom in for DE filters. Make sure you have the correct MPV for your filter.

Note that the Pentair Quad DE filter takes the same multiport as a SAND filter.

Slide Valves are an alternate to an MPV on DE or sand filters.

When replacing an MPV valve you may find the same part number used on valves in different colors and different fittings for Pentair, Jandy, and Hayward filters. Confirm you have the correct part number and fittings for your filter.

MPV Modes

Filter

Filter is the normal setting for the water to flow through the DE or sand.

Backwash

BACKWASH changes the water flow to wash water over the DE or sand and the dirt will flow out of the MPV waste line with pool water. DE will also be washed out of the filter and new DE will need to be loaded in after the backwashing is completed. A sand filter does not lose sand during a backwash.

Rinse

RINSE is done along with backwash. In DE filters you typically alternate between BACKWASH and RINSE modes three times during a backwash.

Recirculate

Use RECIRCULATE if you have a bad algae problem that is rapidly clogging the filter so you constantly need to backwash. Do the initial SLAM Process on RECIRCULATE until you kill much of the algae. Then filter out the dead algae without the algae continuously multiplying as you try and filter.

Or if you use Floc (that we don’t recommend doing) and intend to vacuum it to waste when it settles to the bottom of the pool. Run the filter in RECIRCULATE to not clog the filter with Floc or Clarifier.

Recirculate can be used when the filter is in need of repair - if you can't filter the water, at least you can circulate it

Waste

WASTE routes water directly to the waste line to dump water out of the pool.

Closed

CLOSED shuts off all flow to the filter and pool. Water flow is stopped at the "PUMP" port

Troubleshooting

Leaks to Waste Line

If water is leaking to the waste line while in FILTER mode it is likely a leaking spider gasket in the MPV that needs replacement.

Broken Handle

Replacement handles are available for many MPVs. The Valve handle can be removed by tapping out the handle pin. A helper may be needed to push down on the lid to compress the spring while you tap the pin in for a new handle.

Leaks Around the Valve Handle

There are O rings on the stem underneath the handle that wear and may need replacement.

"one direction only" rotation of the multiport valve?

It's a common discussion, but not everyone does it. In reality, it shouldn't matter and many manuals do not even touch on it. When the gasket is lubed prior to assembly, the (depressed) valve should slide nicely either way. However some feel that the gasket may become worn or almost trained to allow the valve to move better in the same direction to avoid pinching later, especially with age. By that time, it's probably time to replace it anyways.

MPV Repairs

Pentair Pool Valve Parts Catalog 2021

Pentair Tagelus Filter/MPV Parts

Spider Gasket

You will find the spider gasket glued in and you will need to remove it using an xacto knife, needle nose pliers, or a spudger.

For a Pentair MPV gasket you need an exacto knife and a small flathead screwdriver. Use the exacto to cut the sides of the gasket in between both sides of the tracks. Use the screw driver to peel the rubber from the bottom. If it takes you longer than 20-30 minutes, quit and replace the whole mulitport. Because nothing on earth seems to loosen the rubber from the tracks.

Depending on the specific model of the multiport, Pentair recommends gluing the spider gasket in place. They recommend Loctite 401 or 416, but the Permatex should work as long as you don't get carried away with it.

Grease the spider gasket with a pool lube.

Jandy BWVL-MPV-80

If there is a leak around the edge of the Jandy MPV then Jandy E-7-S2 or O-479 generic should be the replacement O ring. Dry the parts, use a bit of silicone sealant and assemble while the silicone is still wet.

Head-Loss Specs for Multiport Valves

If anyone needs head loss specs for Pentair, Hayward, Praher or Sta-Rite multiport valves, the following info may help.

The Praher website (Praher Plasitcs appears to be the manufacturer of some Pentair, Hayward and Sta-Rite multiport valves).

Page 31 of the Praher catalog has cross references for these multiport valves.

SM2-PP2 is the Praher model# which is cross referenced to the Pentair 2" Multiport Valve for DE filters. The owners manual for these Praher multiport valves includes head loss graphs.