How a Multiport Valve Operates

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There are three major types of pool filtering system: cartridge, sand, and diatomaceous earth (DE). Sand and DE filters use a multiport valve primarily to help clean or backflush the filter media. Cartridge filters do not have multiport valves. These filters are cleaned by removing the cartridge and spraying it with a garden hose. A typical multiport valve has 7 settings: filter, backwash, rinse, waste, closed, recirculate, and winter. This guide explains the function of these setting and shows how they circulate water in a typical sand filter. The operation of a DE multiport valve is very similar.

Video

Step by Step

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Step 1

There are five ports into and out of a typical multiport valve. Three are shown in this picture. The top left port, labeled "PUMP", brings unfiltered water in from the pump. The middle left port, labeled "RETURN", sends filtered water back to the pool. The middle right port, labeled "WASTE", sends water to an external drain hose.

Step 2

The other two ports control flow though the filter. This picture shows the valve as it is connected to the inside piping of the filter. At the bottom of the valve, a pipe port connects to the collection tubes (laterals) on the bottom of the filter. The area around the pipe on the bottom side of the valve directs water to the top of the filter. This picture shows water flow for a "FILTER" setting. Water will flow in the opposite direction with a "BACKWASH" setting. The next series of steps explains how each of the valve setting directs water though these ports. CAUTION. When selecting a valve setting, make sure that the pump has been TURNED OFF and always depress the handle before turning.

Step 3

FILTER. This is the normal setting for filtering your pool water and for regular vacuuming. Water from the pool is pumped into the "PUMP" port to the top of the filter. Contaminates are removed as the water makes it way to the bottom to be pushed back up through a central pipe to the "RETURN" port and back to the pool.

Step 4

BACKWASH. After a period of time, the contaminates start to clog the sand to the point where water flow is significantly diminished and the pressure gauge rises 8 to 10 psi above normal operation readings. To clean out the contaminates, you have to backwash the sand. In the backwash setting water flow is reversed though the filter. Water comes from the "PUMP" port down the filter through the central pipe, then back up through the sand to flow out the top exit of the filter and out the "WASTE" port to an external drain. As the water flows up though the sand, the sand is lifted about 7 inches above its normal height releasing the trapped contaminates to be purged out in the waste water.

Step 5

RINSE. After backwashing, the sand is loose and needs to be reset. Also any dirty water from backwashing has to be rinsed out of the filter to waste to prevent it from returning to the pool. With the valve in rinse mode, water is directed from the "PUMP" port to the top of the tank to compress the sand. As in the filter setting, the water flows down though the sand and back up though the central pipe but instead of going out the "RETURN" port to the pool, the water is diverted out the "WASTE" port.

Step 6

WASTE. This setting is used to bypass the filter when you want to vacuum the pool after an algae treatment or to lower the pool level. The water enters the valve though the "PUMP" port and exits though the "WASTE" port.

Step 7

CLOSED. This setting is used for shutting off all flow to the filter and pool. Water flow is stopped at the "PUMP" port.

Step 8

RECIRCULATE. This setting is used to bypass the filter during certain pool cleanups and chemical treatments when you don't want the water contaminating the sand. Water enters the valve through the "PUMP" port and exits back to the pool through the "RETURN" port.

Step 9

WINTER. Use this setting when you are closing down the pool for the winter. This will allow water to drain from the valve.

Comments

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(1 to 40 of 333)

Anonymous  Posted: 6/24/2019 

I replaced my old MPV with aPL0714. When my setting is on "filter" a steady stream of water comes out the waste port. I'm losing a fairly large amount of water this way. Any Ideas?
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InyoPools Product Specialist  Posted: 7/3/2019 

You may have a defective unit, I suggest contacting our customer service to determine the issue with your valve.
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 Posted: 6/2/2019 

When we change the mpv to bypass to waste to clean out floc it will go to waste but then about 10 min later it starts to come out of the return.. any suggestions??
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InyoPools Product Specialist  Posted: 6/6/2019 

Give this a read, it will give a few things to check or replace: How to repair a leaking Hayward backwash valve
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 Posted: 5/31/2019 

Which setting on my multi valve should I run my pump on
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InyoPools Product Specialist  Posted: 6/6/2019 

Take a look at step 3. All the settings are explained in each step.
 Reply

Anonymous  Posted: 5/16/2019 

When recirculating on a multi port valve should the gauge show a pressure reading/
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InyoPools Product Specialist  Posted: 5/16/2019 

The gauge will not show a pressure reading when the valve is set on recirculate.
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Anonymous  Posted: 5/16/2019 

Thank you
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 Posted: 5/3/2019 

The multiport value was removed from my hayward sand filter( just the top) and now we can't remember how to put back on correctly. Is there a way we can tell? We don't want to ruin the filter or the pump. PLEASE HELP!!!
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InyoPools Product Specialist  Posted: 5/3/2019 

The Hayward valves should have a notch in the top assembly. This notch in the cover should match up to the notch in the valve body. You can see the notch in the top assembly image. It's in the 5 o'clock position. Click Here
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 Posted: 5/22/2019 

Most Hayward multi-ports have a flat side on one of the "ears" where the screw holes are located. Line up the flat spots and you're good to go.
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 Posted: 4/16/2019 

I need to replace my multiport valve, but it is very old and the sticker has faded. I can read the numbers 808-0048-LBBA; howhowever, I cannot find one to purchase. Can you recommend a similar one?
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InyoPools Product Specialist  Posted: 4/16/2019 

Hello Cassy - What is the make and model of your filter? This will help us determine the multiport valve.
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 Posted: 4/16/2019 

I believe it's a Haywood sand filter, but I honestly am not sure. The pool, pump and filter are all very old and came with the house. The stickers on top of the multiport and the rest of the equipment are mostly worn off, but those that are not are so sun faded that you cannot read them. The only numbers I can see are the ones posted in the original question. I am hoping I don't have to replace the whole filter.
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InyoPools Product Specialist  Posted: 4/16/2019 

Email a couple pictures of the filter and valve to upload@inyopools.com. We should be able to ID the correct replacement.
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 Posted: 4/14/2019 

What is the best way to drain a hurlcon filter below the level of the lights? Do u just turn it to waste? What happens when the water gets below the skimmer
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InyoPools Product Specialist  Posted: 4/16/2019 

Hello Craig - You can drain the pool by turning the valve to waste. If you plan to drain below the skimmer, you have to close the valve to the skimmer and open the main drain.
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 Posted: 1/26/2019 

I have a Hayward pro grid 4020 DE filter. It has a slide valve that is always breaking. Should I replace it with a 4 or 6 position multi port valve?
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InyoPools Product Specialist  Posted: 1/28/2019 

Hello Bill - We would recommend the 6-position valve. The 4 position valve would not have the ability to rinse and that is a nice feature to have after backwashing. 
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 Posted: 12/23/2018 

Accidentally left my filter on "filter" setting rather than "Winter" setting for the winter. Now everything is frozen and cannot switch to winter position- will the spider valve need to be replaced in the spring?
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 Posted: 2/16/2019 

Get a hair dryer and go out on a sunny day and thaw it out and then switch it to Winter. You want to keep ice from cracking the valve, so hopefully that hasn’t happened already.
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InyoPools Product Specialist  Posted: 1/3/2019 

Hello Ed - that will have to be determined once the water melts and you can check the valve for cracks and the o-ring for tears.
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Anonymous  Posted: 1/3/2019 

Thanks Matt!
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 Posted: 11/24/2018 

Leak out the waste port in recirculate setting but not on filter setting. Is it correct to assume it’s just a failed portion of spider gasket that’s not involved in all settings? I’m going to take top off to visibly inspect tomorrow as I’m more concerned that unfiltered water could be returning to the pool in filter mode due to a failed gasket.
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InyoPools Product Specialist  Posted: 11/26/2018 

Hello David - I agree that it is most likely the spider gasket. Open up the valve and check for any irregularities on that gasket. 
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 Posted: 11/26/2018 

Thanks. Yes it needs to be replaced. Bad idea to try replace and glue in near or freezing temps?
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InyoPools Product Specialist  Posted: 11/27/2018 

For two reasons, I would recommend waiting until it warms up to replace the spider gasket. First, the pool needs to run when there is a potential for a freeze. This will prevent the water from freezing and damaging the pipes. That's assuming that the pool wasn't winterized and closed. Second, the spider gasket should be glued in place using RTV silicone. The cure time is usually 24 hours. Freezing temperatures can really delay the cure time. This means the system would have to be down longer.
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 Posted: 1/6/2019 

I just glued in the new gasket as the next few days will be above freezing overnight. I did my best to get all the old glue out without gouging the channels; think some was still in there even after using acetone. Gluing in the new one with rtv silicone seemed to go fine, but when I screwed the top back on tight, the handle became loose. It seems that since the new gasket is not worn down like the old one, it’s pushing the spring up. It doesn’t seem like pushing on the handle releases any more tension so I imagine that when I rotate the valve (once cured), there will be contact against the gasket. Will that dislodge the gasket?
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InyoPools Product Specialist  Posted: 1/10/2019 

If the gasket is in there flush, the diffuser should not dislodge the gasket.
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 Posted: 11/15/2018 

If my pump has a freeze protection system what does my filter need to be set on?
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InyoPools Product Specialist  Posted: 11/15/2018 

Hello Whitney - the valve should be set to its standard "FILTER" mode used for daily filtering.
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 Posted: 10/23/2018 

If I don't have a WINTER setting on my MPV what setting should I leave the valve on during the winter months?
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InyoPools Product Specialist  Posted: 10/23/2018 

Hello John - Some manufacturers do not include a "Winter" position on the MPV. In this case, push the handle down and rotate it so that the pointer on the valve is between any two positions. This will allow water to drain from the valve. You'll leave it in that position until you open the pool.
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 Posted: 9/18/2018 

Thank you. Very easy to understand again thanks
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 Posted: 9/8/2018 

On which port of Multiport valve we can Back wash
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 Posted: 4/16/2018 

Thank you for the feedback, Robert!
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 Posted: 4/15/2018 

Thank you. No one else has made it make sense. Thank you for your time.
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 Posted: 1/24/2018 

Marilyn - Check your spider gasket at the bottom of your MPV to see if it is damaged. It provides the seals to control the flow in the various modes. See our guide on "How to Replace a Spider Gasket on a Multiport Valve". If the gasket is ok, you may have a blockage in the return pipe coming out of the MPV. To blow this pipe, you may have to cut it out of the piping system.
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 Posted: 1/24/2018 

When I put the multivalse on backwash, rinse and waste the filter works. When I put it on filter and circulate there is no water going back into the pool. Please can you tell me what I should check to fix this problem. Thank you
 Reply