How a Multiport Valve Operates

Written by:  Danny Rhodehamel
rate: 
 
 (3.82 OUT OF 5 STARS ON 25 RATINGS)

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.

Tips & Warnings

Video

Step by Step

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 (1 to 40 of 218)

Add Comment



User: Inyopools

FOMBELLBOB - It is possible on some multiport valves to reinstall the rotor 180 degrees out of position, so the modes don't operate properly. See our guide on "How To Replace a Pool Multiport Valve Handle" for an example of how this could happen. If this isn't the problem, you might trying cleaning the grids again to clean out the excessive dirt you filtered out of the pool. Also check the breather tube that goes from the bottom of the filter tank to the top. Make sure it isn't clogged and that the screen at the top of the tube is clear.

User: FOMBELLBOB

I have a nautilus ns36 de filter and a Pentair 1 1/2" multiport valve. we had a bad storm that left a lot of dirt in my pool.After filtering the pool is clean but don't have the sparkle it had before the rain. when I turn off the pool now I get de flowing back in from the suction ive replaced all of the rubber internal in the filter and multi valve and still I get de flowing back in the suction my pool is 24 yrs old and I never had this happen I also replaced the gridS in the filter 2 yrs ago.im not sure what is going on.please any suggestion. I was wondering if the rotor was put back in the valve the wrong way and letting a flow go back in the suction when shut off.ALSO I HEAR A GIRGLE SOUND FROM THE FILTER WHEN THE DE IS FLOWING BACK INTO THE POOL.

User: Inyopools

recirculate - No, the pool would not drain. In recirculate mode the filter is bypassed so you have a straighter line between the pool to pump ports and the pool return ports. Water may move a little when the pump is shut off but it would go back into the pool.

User: 

If I set my filter to recirculate and the filter timer shuts off the system will it drain the pool?

User: Inyopools

backwash failure - Check your spider gasket to make sure it is not damaged. Remember to shut your pump off when you move the MPV handle to switch modes, and always push the handle all the way down when you move it. See our guide on "How to Replace a Spider Gasket on a Multiport Valve" for more information.

User: Inyopools

Stan - The MPV is part of the DE filter. If you are suggesting leaving the DE filter in place and placing a new cartridge filter next to it, I don't see why I think you are saying will not work. With the MPV in "Waste" mode, you would be bypassing the DE filter and going straight into the new cartridge filter. Kind of jerry rigged but I don't see why it wouldn't work.

User: 

Replaced the multiport valve unit, but now the water doesn't leave the pool during backwash cycle. After running I got the backwash cycle for a few minutes,a suction forms in the incoming line forcing a collapse in the return line

User: Stan

I want to swap my hayward pro grid de with a cartridge filter. It looks like the inlet outlet ports are reversed on the cartridge filter compared to the de. Can I simply connect the new cartridge filter c4030 to the multiport (seems easiest because it's a straight matchup) and simply relate the backwash position as the filter position and be sure to never use the original filter position since that is now backwash?

User: Inyopools

prime and backwash - Sounds like you may have two problems. Losing prime is a suction side problem - before the or in the pump. You probably have a suction leak in the connections between the pool and the inlet port to the pump. See our guide on "How to Identify and Correct Air Leaks".  Also check an see if you have debris clogging your pump's impeller. See our guide on "How To Clean Out a Pool Pump Impeller". The backwash issue is on the discharge side of the pump and is most likely a damaged spider gasket that needs to be replaced. See our guide on "How to Replace a Spider Gasket on a Multiport Valve" for instructions on replacing the gasket.

User: 

I replaced the sand in my filter but I can't get the pool to hold the prime. I noticed that when I move to recirculate some water comes comes out through the backwash tube. Are these 2 issues related and how do I fix it?
Julie

User: Inyopools

angie - The only thing I can think of is the unions may have been over-tightened. Please call Hayward at 866-772-2100. They may have other ideas.

User: angie

I have received two Hayward SP0715X62 Pro-Series Vari-Flo Control Valve with Gauge and they have both developed hairline cracks around the pump and return ports within 2 days of installation. They are two different valves and both brand new. We installed them according to specs but still have this problem...please advise.

User: Lou

I thought of that so I emailed Hayward customer service. He told me the same thing. The ports are reversed so he sent me a label to put on the new assembly to align with the ports for a DE filter application. I took a closer look at the old assembly for the DE filter. It is very worn and I wonder how it lasted this long. Hopefully with the new assembly, the handle will turn much easier. It never turned easy and I thought this was normal not having any experience with pools before. I guess you live and learn.

User: Inyopools

Lou - DE Multiport valves are sometimes different from sand Multiport valves. There ports are reversed. You would be safe using this assembly for the sand filter MPV.

User: Lou

Thank you for the information on replacing the spring and bearing. I decided after reading the instructions on how to do this not to attempt the repair. The valve is at least 13 years old and I'm sure other things will need replacing (I'm not the original owner of this). Instead I decided to order a new handle and cover assembly. The only other question I have is what is the difference between this part for a DE filter vs. a sand filter?

Thank you for your help.

User: Inyopools

Lou - Sounds like the non-metallic bearing is your problem. If it is broken, it will interfere with the rotation of the handle. See our guide on "How To Replace a Pool Multiport Valve Spring" for information on how to get to that bearing.

User: Lou

The handle has always been hard to turn and makes creaking noises when it is moved. With the replacement of the spider gasket it got worse. When I push it down all the way there is still rubbing and very hard to turn. It looks like the non-metallic bearing is broken in the middle and not providing the pivot action needed. This being the case, should I replace the bearing since a new one came with the rebuild kit. Or buy a new assembly which has the handle, bearing, cover plate, spring, and cone? This would be SPX0715BA3.

User: Inyopools

Lou - There shouldn't be any contact between the spider gasket and the valve housing when you rotate the valve handle. Are you pushing the handle down all the way when you rotate the valve? Is there something preventing you from pushing the handle down all the way?

User: Lou

This is a follow up from my previous post of 4/23.
I replaced the spider gasket and the cover gasket. The old spider gasket has worn down ridges due to the abrasive action of the DE. I super glued the new one in as you said and then put it back together. I noticed now that the handle is hard to move beyond say 180 degrees to the other functions. I took it apart and the gasket is still in place and not damaged. Should I lube the top of the spider gasket with o-ring lube now? Or just work it in?

Thanks,

Lou

User: Inyopools

Ruetsca - WINTER mode allows water to drain from the lines so it doesn't freeze in the winter. Try putting the valve in CLOSED mode. It effectively shuts off the valve.

User: Ruetsca

I have a Hayward Vari-Flo XL Valve, which is above grade. What position should it be in when I am filling the pool for season (using a hose). I just bought the house, and it was still in "winter" mode. I seem to be losing a lot of water? Any suggestions?

User: Inyopools

Lou - The industry has evolved from not gluing the spider gasket to only selling the gasket integrated with the diffuser in some cases. The popular Hayward SP714T valve, for example, only sells the Key/seal Assembly - Diffuser with the gasket glued in. If you have that valve, you don't have to worry about gluing the gasket in. It just costs more to buy the assembly. Otherwise, I would go with gluing the gasket in at the spoke tips. It will be easier to remove if you have to replace it again later. Two tips: the rounded side of the gasket goes up, and after the gasket is replaced, remember to turn off the pump each time you change the valve position.

User: Lou

Thank you for suggesting that I replace the spider gasket. I've watched several UTube videos and read procedures written by many people on how to change this gasket. It seems that few agree on how much and/or what adhesive to use. Some say use no adhesive at all. Others say use it only on the spoke tips. While others say use it on all surfaces on the bottom. Who is correct??? This is why I am reluctant to replace it if it is not that bad yet. I could be making the situation worse.

User: Inyopools

Lou - Sounds like your spider gasket has a leak between the Waste port and its adjacent port, and of course the best solution is to replace the spider gasket. Putting a shut off valve on the waste line should work as a temporary fix, but you will have to remember to open the shut off valve when you set your filter to Waste or the pump water will have nowhere to go and you may damage your system.

User: Lou

I have a DE filter with an SP0715 Hayward multiport valve. There is always a slight amount of discharge out the waste port when the pump is running. Maybe about 2 gallons/day. I know the valve's spider gasket may need changing. I was wondering, as an option can I place a shut off valve on the waste port instead. Would this do any damage or cause a problem to the muliport valve or filter?

User: Inyopools

Chloe - Sounds like you may be at the point where you will have to vacuum the rest out with a large heavy duty wet vac. You should be able to rent one of these from a local hardware or rental store. You will also need to buy the following equipment if you don't already have it.
Clear Triangular Vac Head-Deluxe
Swimming Pool Telescopic Pole
Deluxe Inground Vac Hose 1 1/2 inch x 35 foot

User: Chloe

Hi please can you help me , our pool man has let us down a number of times so we turned off our pool and left it for Afew months , it's dirty, I had it on waste all day and most of water has gone but won't drain anymore still about 1 foot of water left The dirt has settled to the bottom of the pool and won't drain anymore ! Please help me . I haven't a clue what to do. Please make it somple instructions haha

User: Inyopools

sand in pool - Check your multiport valve gasket again. You may be getting vacuum debris leaking back through the recirculate path when you are in filter mode. Also try closing down the suction post a little to see if that helps - should reduce pressure. Finally, you may have a leak in your suction port line that is sucking in debris at the leak. You may have to have someone look at that pipe.

User: 

We have changed the sand, latterals, multiport valve and the impellor on a meteor eclipse sandfilter. It now filters on normal usage. But when I vacuum it goes back into the pool. The psi starts at aboit 19/20 psi on normal run, Could the motor be pushing the water through to fast to properly filter while vacumming

User: Inyopools

MPV Drawing - I would suggest contacting the valve manufacturer. They should have a picture of your valve label in their system that they would send to you.

User: 

where can I get a drawing of the positions of the multiport valve.

User: Inyopools

Low pressure - A clogged impeller is a good place to start. See our guide on "How To Clean Out a Pool Pump Impeller". If that's not the problem, try our guide on "How To Determine the Cause of Low Water Flow".

User: 

Installed a new multi port valve and sand. Now cant get the pressure above five. Pressure good at intake but low on all discharge settings cant find any problem. Could the impeller be clogged

User: Inyopools

TC - When your gauge reads 0 while your pump is running, I would assume that your pump has lost prime - the strainer basket has no or little water in it. That would indicate that you have a suction side leak in the connections of the pipes coming from the pool to your pump. Try soaping up the suction line connections to see if bubbles get sucked in to a leak. I would concentrate on the line that you shut off to get the system working. The leakage around the chlorinator is on the discharge side of the pump, and though annoying, would not cause your system to lose prime.

User: TC

My filter has been giving me problems. Its a hayward s244t sand filter I believe. I just bought the house and trying to figure out how to get everything running. I dont think the system is very old. I finally played around with it long enough yesterday after 3 pool guys came out and couldn't fix the issue. Sometimes it filters and sometimes it wont. Sometimes the guage won't leave off of 0 and right now its at 10 and the filter is running. I was finally able to backwash and rinse it yesterday. Im afraid that if I turn it off it wont work again. I have the right valve turned off (not sure where it leads to) and it seems to be working fine vs both valves open leading to the skimmer by the pump. Please advise on what could be the issue. Even though its working there has to be something faulty. There is also some leakage around the inline chlorinator.

User: Inyopools

low pressure - Here's a link to our guide on "How To Correct Low Water Pressure in Your Pool System". It has suggestions on how to resolve common low pressure issues. If you haven't changes your filter sand in the last 5-7 years, that also may be a problem. Here's our guide on "How To Change Sand In a Sand Filter".

User: 

I have low pressure in the filter position. Backwash several times no change in operation. Im not sure if its the multi-port valve or the sand can you please advise. The filter is a haywood SP 714.

User: Inyopools

Phil - Assuming the filter is all installed, the start-up sequence is to first set your multiport valve to backwash and run it for 2-3 minutes, then set the valve to rinse and run for 30 seconds, then set the valve to filter for regular operation. Remember to shut off the pump each time your change filter modes, so you don't damage your filter gasket. If you have a lot of debris in your pool, get as much of that out of the pool with a hand skimmer before you run the pump, so you don't clog up the filter.

User: Phil

Great web site! I am installing a new above ground pool and am using a multiport filter, what do I need to do when I switch it on for the first time? Thanks

User: Inyopools

chronoallison - Sounds like your spider gasket in your multiport valve is damaged. See our guide on "How to Replace a Spider Gasket on a Multiport Valve". Remember to always turn off the pump before changing the valve setting.

  1     2     3     4     5     6    

Back To Top

Tips & Warnings

Continue backwashing until the water shows clear in the sight glass on the side of the valve.

Don't backwash excessively. Contaminates in the sand actually help the filter work more effectively - to a point. Monitor your pressure gauge for an 8-10 psi rise.

Never move the valve handle when the pump is on.

Don't vacuum your pool in backwash mode. You may clog the collection pipes (laterals) at the bottom of the filter.


Please Note:

Inyo Pool Products is not responsible for any injury or damaged equipment
while using our guides. Using our guides is doing so at your own risk.
These guides are suggested use of your pool or spa equipment and may vary
depending on which product you are using.