How a Multiport Valve Operates

Written by:  Danny Rhodehamel

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


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 164)

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User: Inyopools

KrisM - If you have water flowing where it shouldn't be, it still sounds like you have a bad spider gasket. Recheck your gasket for flat spots or small tears. Then check to see if you have any cracks in the valve itself. Also check that you don't have a weak spring under the handle. A weak spring could allow water to pass over the gasket.

User: KrisM

Cant clear my cloudy pool. All chemical levels are in ideal range. When I backwash some water still goes into the pool. When I vacuum some dirt goes into the pool. Opened the valve to look at the spider gasket, looks ok. Do I need a new valve? Can't tell if the valve is seating properly in the right spot. How do I tell?

User: Inyopools

backwash leaking - Sounds like your multiport valve spider gasket is blown and will have to be replaced. See our guide on "How to Replace a Spider Gasket on a Multiport Valve".


i get water out my backwash port when in filter mode is the head bad ? do i need a new head ? can i rebuild head?

User: Inyopools

Jason - The only difference between your filter setting and rinse is where the water is being discharged - filter goes out the return port to the pool. Rinse goes out through the waste line. If Filter works well, than we know that the filter and valve are working up to the discharge ports. If neither rinse nor backwash works, that would imply that something is wrong with the waste port. Is there anything blocking the waste line?

User: Jason

I put a new multiport valve on our pool. It has plenty of pressure when filtering, but when backwashing and rinsing the water is just barely coming out the waste line. If I push the handle down while it is set on backwash it pumps better but still not as good as last season. As soon as I let the handle go it looses pressure again. Up until this year it worked fine, it would backwash and rinse with enough pressure that it looked like a fire hose. It started doing it with the original valve, so I bought a new one thinking it might be seals going bad, but the new one isn't working any better. Any idea what may be causing it?

User: Inyopools

Guy C - I'm not sure what you what to do but I think the answer to your question is no. You cannot use the multiport valve to divert water to the solar panels. The return port eventually goes back to the pool. You could have it goes to the solar panels from the filter. In recirculate mode the valve would bypass the filter, but when you put the valve in filter mode the water would still go to the solar panels. Usually people put in a pair of diverter valves after the filter to direct the water to the solar panels or to bypass the panels and go directly to the pool.

User: Guy C

Can I use the re-circulate setting on my filter to divert water to a solar heater ? Will this work

User: Inyopools

debi - If you have a side mounted valve, check to see if the air relief tube inside the tank is clogged. It runs from top to bottom to relieve pressure at the top of the tank. Check to see if your motor's impeller is clogged. See our How To Guide. If you have very dirty water, it may be clogging your filter. When initially cleaning, dump the dirty water from the bottom of the pool, out the waste port.

User: Inyopools

mary - Generally you cannot use any kind of multiport valve on a Triton filter. The spacing between the input and output ports vary between filters.

User: debi

I have a sand filter and have had it about 4 years. When I first started it up it did not sound right when I shut it off, water shot back thru the skimmer basket about 2 feet high. I finally got it going but when I tried to clean the bottom it will run a few minutes and lose suction. I changed the sand out and check all tubes which look fine. I have not water leaks but I can not figure out what to do to not lose suction.

User: Inyopools

homeboy - You may have installed a pump that was stronger than your old pump. A pump's real Total Horsepower (THP) is equal to the HP on the motor label times the Service Factor (SF) on the label. Compare the THP of your old motor with the one of your new motor. Pressure gauges do go bad. Try swapping out yours with a neighbor's to see if you need a new one. Finally, the small leak in the pipe between the pump and the filter will not cause your water pressure to go up. If anything, it would relieve some of the pressure.

User: Inyopools

mison2014 - We do sell the valve body only. However the cost of the body is almost equal to the cost of the whole valve. At this point, I would replace the whole valve.Click on underlined items for more details and prices.

User: mary

Can I use any kind of multiport valve on a Triton filter as long as the fittings are the correct size?

User: homeboy

I just installed a new Hayward pool pump in my inground swimming pool and the pressure guage seems to be high (20 - 23 PSI). It was only between 16 and 20 PSI with old pump. Also my pressure guage go to 3 when the pump is turmed off and have a small leak in the pipe ging into the sand filter. Is the pressure guage broke or can the small leak be causing this problem.

User: mison2014

I have a Hayward DE4820 filter with a Hayward Sp715XR50 vari flo valve. I only use filter, Backwash, Rinse and waste. The body has a crack so I must replace. Is there another valve I can replace it with?
Or do you sell only the body for this valve. the controller top is in great shape as i replaced it about 4 years ago.

User: Inyopools

Stones - Leaking out the waste port while filtering is generally caused by a damaged spider gasket. See our How To Guide on Replacing a Spider Gasket. Typical psi while filtering is 10-15 psi.

User: Stones

My sand filter seems to be working ok but I'm not sure what my normal psi should be while filtering. Also, I have a leak out of my waste port while I'm filtering. What could be causing that?

User: DAR

Well it's been about a week or so...currently I have not vacuumed the pool yet, it's no longer green at all, there's a bit of cloudiness but i can see the third stair....the filter will run up to 3 hours before it needs a must be the amount of fine particulate in the pool...but it is odd that this has happened only in the last 2 years, it's a 10 year old pool and the number of trees nearby has been halved....

User: Inyopools

DAR - If your water was very dirty when you opened your pool and you are processing this water through your filter, you may be clogging your filter repeatedly and you will have to backwash frequently. If you still have dirty water, try vacuuming the floor and diverting that water to the waste line. Also if you have a side mounted multiport valve, check the air relief tube that runs from the top to the bottom inside the tank. If this tube gets clogged, you can have back pressure building up in your filter.

User: DAR

I have a pool with an astral sand filter and a hayward pump. The pool was just opened; the filter will run for maybe 30 minutes and then the water output drops off dramatically; the pressure really does not change from 1 - 1.5. If I shut the pool off for a while, the output is strong but then again drops off...once the flow gets going there is no air in the filter basket.

this happened last year too and I changed the sand in the filter ad the problem cleared up but I do not think thats the cause of the problem...I cant keep backwashing every 30 minutes and I'm afraid of what will happen to the pump if i let it run that way, right now it is running on reciruculate and it is producing a lot of output which suggests that the filter is the issue.

User: Inyopools

5deeds - The small leak in your multiport valve will not cause high pressure. In fact it might be relieving some of the pressure in your filter. The most common cause of high pressure is a clogged filter. Spraying off the debris is not always sufficient. Periodically you should soak the cartridge with a cleaner/degreaser to remove oils, grease, suntan lotion, chemicals that clog the filters. We sell this Cartridge Cleaner. Another common problem is an oversized pump. A relatively inexpensive solution to this problem is to replace the motor's impeller with one a size smaller.

User: 5deeds

Can a small leak in the multiport valve cause high pressure in the pump? We have cleaned filters, put new O-rings in chlorinator and around skimming basket. Not sure what else to do except that I did notice some water leaking around multiport valve.

User: Inyopools

Canuck - If your pool has a lot of debris in it from the winter, you should set your multiport valve to waste. Clear the large pieces out with a net. After your pool is relatively clean, switch to filter. If you did not backwash your filter before you closed for winter, I would also throw in a backwash cycle after the waste cycle.

User: Canuck

When my pool was closed for the winter the valve was set on winter (I live in Canada). When openning the pool after winter, once drain plugs replaced, water level adjusted etc, and am about to start the pump after priming, what should the vari flow valve be set to; filter, bachflush, waste?

User: Inyopools

Dallas - If this just happened during normal operation, I would guess that the spider gasket in your multiport valve is blown. See our guide on "How To Replace a Spider Gasket on a Multiport Valve" for more information.

User: Dallas

My multiport is running backwards. When set on backwash itis running on filter. Is this an easy fix?

User: Inyopools

Steve - If you just have a little blowback, I wouldn't worry about it. If it gets worse, you may have a damaged spider gasket in the top of your multiport valve. See our guide on " How to Replace a Pool Multiport Valve Spider Gasket" in our list of How to guides under Filters/Multiport Valve.

User: Steve

I've recently taken over a house with a swimming pool and went to backwash the sand filter fitted with a multi port valve.In the backwash position a small amount of dirty water was expelled from the return ports to the pool.Is this normal?I am able to close the return line to the pool if required.

User: InyoPools

EricGM - Please refer to the following How To Guide for instructions on cleaning a green pool: How to Clean a Green Swimming Pool.

User: EricGM

If a pool has been idle for a while (with some mold growing) and uses the multi port valve system. What would be the best process for opening the pool. Which setting should I use to completely filter the water through the skimmer and what chemicals should I use?

User: InyoPools

jennifer - Most pool owners do not use this valve position. It is usually used to empty the pump basket when the pool sits much higher than the pump.

User: jennifer

What is an example if why the closed setting would be used?

User: InyoPools

Jp - You may have a blown spider gasket in your multiport valve. See our how to guide on replacing a spider gasket. Make sure that you remember to turn off the pump each time you have to more the valve setting.

User: Jp

After back washing my pool I turned the pump Back to filter and water is coming out of the backwash pipe. What happened? I back washed the other day also because my pool was green. So to clean it I back washed, applied chemicals for 36 hours and then back washed again. Only the second time is when it started coming out the backwash pipe. Please help and thanks

User: InyoPools

Jaime - Sorry for the late response - I lost this one. Did you and can you shut off the pipe to the skimmer. To establish prime you have to shut off any input to the pump that isn't covered with water. Otherwise it will suck in air to the pump and cause the pump to lose prime.

User: InyoPools

vacuuming filter position - If you are vacuuming significant debris or have algae issues, use the WASTE position to keep debris/algae out of the filter. For normal vacuuming, use the FILTER position. A RECIRCULATION setting bypasses the filter but returns the water (and debris) back into the pool. You should never vacuum on the BACKWASH setting. It would clog the laterals at the bottom of the filter.


I have a Hayward motor vari flo xl and need to know what position the arm should be in to vacume the pool? Recirculate or backwash or waste out? Thank you!

User: Jaime

I am draining my pool to have some rust stains cleaned on the plaster of my in ground gunite pool. I drained it all the way to the bottom by using the skimmer/main drain valves switches while on waste mode. It rained for 2 days and filled up about a foot of water in the deep end area and I can't get the pump to drain out the rest following the same steps. Do I need to do something special? I've tried to "prime" the Hayward pump basket by adding water but it's not helping either. I have a Hayward Tristar pump. Thanks.

User: InyoPools

LynneB - Not sure where the water is coming out and going all over the floor. If it's coming out of the waste port, you should have waste water hose attached to the waste port to take the water out to a drainage area.

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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.

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.