How a Multiport Valve Operates

Written by:  Danny Rhodehamel
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 (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 (41 to 80 of 216)

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User: Barb E

Does it matter which way you turn the multiport valve? should you always turn it clockwise? I am having a problem with water flowing out when the valve is in filter setting. At first I thought the pool had a leak until I realized there was water flowing out the blue discharge hose when the valve was turned to filter.

User: Inyopools

Sandy pool - Check to make sure that your valve's spider gasket is not torn and letting dirty water back into the filter cycle. Also, if you just changed your sand, the very fine sand may be getting through the filter. Vacuum this sand off the bottom of the pool and dump it out the waste line.

User: Sandy pool

After I clean my pool to waste, then backwash, rinse and finally filter sand keeps flowing back into the pool. What do I do?

User: Inyopools

Suzanne - If you are going to a cartridge filter, you can get rid of the multiport valve. They are only used with DE and sand filters and have no other application.

User: Suzanne

I have an old Hayward DE filter and old speck pump. Since the pump has a hairline crack I will be replacing it and have decided to get rid of the DE filter too...I want to go with a cartridge filter. I am trying to get the right filter/pump and am wondering If I should also get rid of the multiport since I wont actually use it or can it be useful in another way to me?

User: boogerdave

The whole valve assembly is new . . right out of the box. I have checked both the gasket (glued in) and also removed the spring to try and stretch it a little. I guess I will order a new spring and give that a shot. When I switch from low to high speed, I can see the selector handle lift a bit . .

User: Inyopools

boogerdave - Sounds like water is still getting past your spider gasket. Check that gasket again. Be sure to turn off the pump every time you change valve settings or you will blow the gasket. Also your spring may look good but be weak. Consider changing the spring. See our guide on "How To Replace a Pool Multiport Valve Spring" for more information.

User: boogerdave

I just replaced the waterway multiport valve assembly on my sand filter and now when the pump is on high the water leaks (runs) out of the waste (backwash) port. I have checked the gasket, spring etc and still tends to compress the spring on the selector handle . . then, the leak starts. Funny part is, when the pump hasnt been running for a while, it wont leak at first but within about 5 minutes it continually starts and gets worse. Doesnt do it on low pump speed

User: Inyopools

Pool Start up - Don't use "filter" until most of your winter debris is out of your pool. It will clog up your filter. If you have a lot of heavy debris in your pool, use a net to screen out the big pieces. Then set your multiport valve to "Waste" until most of the smaller debris is out. Then set your MPV to "filter". When you are in "waste" mode, push the debris on the bottom to the main drain to speed up the process.

User: 

What setting should the vari flo valve be on when re starting the pump after the winter? Should I use the waste setting for the first time I vacuum or can I run it through the filter? This is my first time starting the pool on my own so I am confused.

User: Inyopools

Vannessab623 - Pulling the cleaner should not have had an effect on the filter. Check that you still have the filter connected to the pump properly then check to see if you have a damaged multiport spider gasket. See our guide on "How to Replace a Spider Gasket on a Multiport Valve" for more information.

User: Vanessab623

Hi, I have an ingrounf pool with a Hayward sand filter with the multi valve. When we bought the house it had an automatic cleaner. I pulled the cleaner out because it needs to be repaired but now I can't get my filter to work. All hoses are removed and I tried the filter and recirculation setting and neither worked. Can you help?

User: Inyopools

Eric - If you just opened your pool and the water was full of debris, you may have clogged your filter badly. You may have to backwash it several times to get the debris out of the sand. If the water still has a lot of debris, net it out and purge as much of it out through the waste line as you can before passing the water through your filter.

User: Eric

Hi there, I have a Jandy sand filter on a 25k gallon pool with a 1.5hp hayward pump. Unfortunately I cannot give a lot of details on the filter as I bought the house w/the pool and the label on the filter is very worn, but I am able to see Jandy and their logo. But the flow of water back to the pool decreases dramatically after about a couple hours of running after it's been backwashed. I just changed the sand last summer. I can backwash and it seems to have full pressure again, but then after a couple of hours loses most pressure coming back to the pool. Is that a bad multiport valve? It's a waterco multiport valve. I've replaced the center pipe O-ring as well and the main o-ring between the valve and filter is in good shape. Thanks for any direction you can give me.

User: Inyopools

BZ - Check your multiport valve spider gasket. It may have a tear in it.

User: BZ

I have a strange scenario. I have a Hayward Sand filter 244t. When the pump is running, all of the settings on the multiport work fine except "waste". Filter, recirculate, and backwash work fine. When set on waste however, the water discharges, but it is pulsating. There is a smooth flow of water in backwash mode, but waste pulsates badly. Any thoughts?

User: Inyopools

bill - Multiport valves may vary with manufacturers, but according to the Hayward rep, the ports on their Multiport valves are set up differently. For the DE MPVs the top port is "out" and the bottom port is "in". For Sand MPVs the top port is "in" and the bottom port is "out".

User: bill

What happens if you install a multiport valve that says use on de filter on a sand filter? Do they operate differently? I see some that you can use in both systems and some that say use only on de filters.

User: Inyopools

Henry - It depends on where your leak is. Check the spider gasket. See "How to Replace a Spider Gasket on a Multiport Valve". Check the O-ring between the multiport valve and the filter body. And check the O-rings around the stem of the valve that the handle attaches to. See "How To Replace a Pool Multiport Valve Spring". Note, not all valves have the stem O-rings.

User: Henry

What is the problem if water starts coming out of the multiport valve? The problem settles down after a backwash and cleaning out the DE powder but starts up again after awhile. Does the valve have a rubber seal that needs replacing? Thanks for your help.

User: Inyopools

kenny - If your pool has a lot of debris in it, set you multiport valve to "Waste" so you don't clog up your filter. When the pool is reasonably clean, you can leave your valve at "Filter" when vacuuming.

User: kenny

we just moved into a house with an in ground pool. What setting should the filter be on before I vacuumed the pool pls.

User: Inyopools

Spooner - Sounds like you have a leak. Try shutting down one of your suction lines at a time for a day and see if you stop losing a 1" of water for that day, then open that line up and shut down a different one. If that doesn't isolate your leak, try the same procedure on the other side [pressure] of the pump. As for the sand in your pool, see our guide on "How To Reduce Sand in Your Pool"

User: Spooner

I have moved into a house that has a pool and it is the first time that I have had one. The pool has a Hayward sand filter with six (6) settings on the multiport valve, for some reason looses about 6"-9" a week of water. IS this normal? I understand there is evaporation, but that seems a little excessive for evaporation. Also, when it sends water back to the pool there is, what seems like to me, a bunch of sand back into the pool with the water. Is this normal too?

User: Inyopools

multiport valve - It sounded like your valve handle or multiport top assembly was mounted 180 degrees from its correct position. That often accounts for "filter" acting like "backwash" and vice versa. But, if that was the problem, you should have corrected it with the new multiport. I don't know where the hoses are connected now, but the hose from the pump has to be connected to the top port, usually labeled "PUMP". "RETURN" port goes back to the pool and "WASTE" goes out the waste line. Make sure you turn the pump off each time you change the valve setting or you will blow the new valve gasket and water will go out the wrong ports.

User: 

I recently moved into a house with a pool and this was my first year. I'm having serious filter issues. At the start of the season I noticed that whenever I put my filter into the filter position water poured out of the backwash line. When I put it on backwash, the water ran back into the pool, but so did the dirt. I looked online and saw that it might be a bad gasket, so I replaced the whole multi-port. It still does the same thing. I switched the two lines thinking I put them on wrong, but it leaks on every setting. Can anyone help? I'm so frustrated and I don't know what to do. :(

User: Inyopools

Ken - I think you are fighting gravity. The pump on an above ground pool is gravity fed. Your multiport valve works fine in filter mode because there's nowhere for the water to go when the pump is off. When you are in backwash mode with the pump off, you have an open line to the waste port and gravity will pull the water from the higher pool out the waste line. Most AG pools have a shut off valve between the pool outlet and the pump that can stop to flow of water in cases like this. Or make sure the multiport valve is in filter mode when you shut off the motor.

User: Ken

I just installed a waterway multiport valve on my above ground pool. The filter mode seems to work fine but whenever I depress the handle to change modes it dumps water out of the waste port. Additionally, if I have it in backwash mode without the pump on it dumps water out the waste port. Is this normal? This is a brand new valve.

User: Inyopools

Shauna - If the sand in your filter has not been changed in the last 5 years, I would start there. Here is our guide on "How To Change Sand In a Sand Filter". Also check the spider gasket in your multiport valve to make sure it is undamaged. When you turn your multiport valve handle, the gasket seals the different ports so that the water flow in the direction you select. When you rotate the valve handle, make sure you turn the pump off first or you will blow the gasket. Here is our guide on "How to Replace a Spider Gasket on a Multiport Valve"

User: Shauna

I have a Jacuzzi laser sand filter and for some reason it seems to not be filtering through the sand or is improperly being diverted straight back into the pool when we put it on filter it completely stops all water flow back to the pool but if we push down on the dial it flows but still does not flow through the sand, we have put shock in the skimmer and it shoots straight back out through the filter into the pool. We are new to sand filters and have no idea what could be the cause of this if someone could help and tell us how to get the water to divert through the sand and back to the pool the proper way it would be of great help to us, thank you

User: Inyopools

Cloudy water - If you haven't changed your sand for 10 yrs, you should do that now. Sand, or its equivalent, only lasts 5-7 years. Most sand filter owners use the pool sand that you can buy at a local hardware store. And you should fill it to within 6" of the top of the filter tank. See our guide on “How To Change Sand In a Sand Filter” for further information.

User: 

hi i have a hayward sand filter 24" dia X 34 tall. it s 10 yrs old. i cannot keep the water from being cloudy. the chemicals are fine. is it time for me to change the sand ? if i remember right the instructions had me install a very small pebble type media. Could you tell me do u think this is the possible problem and what type of media/ sand should i replace with and how much ? the multi port valve seems to be working fine .. thankyou

User: Inyopools

Sarah - There are generally two plugs at the bottom of a pump either of which could be used to drain the pump. See Step 2 of this link for a picture of where they are: "How To Measure Total Dynamic Head With Gauges".

User: Sarah

My in ground pool/pump is broken and not working. Is there any way for me to drain water out of it while the pump wont work?

User: Inyopools

bella81762 - You could check to make sure your spider gasket in your MPV is not leaking water between the ports, but I don't think this is your problem. Your problem is probably due to a chemical imbalance. We have several guides on correcting an imbalance. See our guides under "Pool Maintenance" for more information.

User: bella81762

hi, i have a hayward filter, and i cannot keep my water clean,,i have been floccing,, and vacuming,to waste it clears and 2 days later is cloudy again, have had the chemicals checked at the store,,,they are perfect, changed the sand, while the body is new,, the hayward variflo, is rather old...is it possible, that for whatever reason maybe the water is not going thru the sand,,,and i need to replace the valve,,,

User: Inyopools

cjames - You may have a damaged spider valve that needs to be replaced. See our guide on "How to Replace a Spider Gasket on a Multiport Valve" for further instructions.

User: cjames

Im new to using a sand filter with a dial top and just bought a used Sand Dollar sand filter. Unable to keep dirty water from coming back into the pool when vac. pool...even when it is in the waste position. PLEASE HELP!!!!

User: Inyopools

Daryl - You are correct. "Drain" is the same as "Waste". "Whirlpool" = "Recirculate". This setting bypasses the filter. And "Test" used with AG pools, blocks the filter and stops the water from coming back into the pump.

User: Daryl

First of all, thank you for this site. Is a great tool for us pool owners that don't get good advice from our local pool store. I have a Jacuzzi MFM filter and the valve settings are different from what I've seen on your site. I have filter, backwash, rinse and winterize. But th there's whirlpopol, drain and test. I'm assuming that drain would be waste, and whirlpool would be filter bypass. I guess test would be closed. Is this right?

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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.


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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.