How To Select a Pool Check Valve - Overview


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There are several types of pool Check Valves. This guide provides an overview of the function, description, and repair or replacement of these Check Valves.

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Step by Step


Step 1

CHECK VALVE PURPOSE - In general a pool check valve in installed in your circulation system to keep water from flowing backwards in the system when the pump is turned off. For common uses of a check valve see "When To Install a Check Valve in Your Pool Plumbing".

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Step 2

CHECK VALVE TYPES - There are two common types of Check valves on the market today: the Spring Check Valve and the Spring Flapper Check Valve. The Spring Check Valve has an internal panel that moves against a light spring to open and shut the valve. The Spring Flapper Check Valve has a flap on one end of the valve that pivots up against a light spring when water is flowing from the pump, then releases down to shut off any opposite flow when the pump is off.

Step 3

SPRING FLAPPER CHECK VALVE - This picture shows the two popular styles of Spring Flapper Check Valve. Both provide access to the flapper mechanism from the top of the valve. One is screwed down with 8 screws. The other is secured with a more convenient twist on Cover Nut.

Step 4

SPRING FLAPPER MECHANISM - This picture shows the flapper mechanism that operates inside a typical Spring Flapper Valve. The Flapper is accessed by removing the top of the valve.

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Step 5

SPRING CHECK VALVES - This picture shows the center panel inside a typical Spring Check Valve. I have used a stick to push the center of the panel to allow flow through the valve. This Check Valve does not open as much as the Flapper valve so would appear to impede flow more than the Flapper Valve.

Step 6

CHECK VALVE SIZES - These Check Valve come in different port sizes to fit the common system piping including 1 1/2, 2" and 2 1/2". Some of the valve are designed to fit two sizes. For example, a 1 1/2 pipe would fit inside the port, and a 2" pipe would fit outside the port. Also these valve come with different spring strengths. Most have a 1/2 # spring for light resistance. Some have 2# resistance for situations with greater head or backflow pressure like solar panels mounted on an 8' high roof.

Step 7

CLEAR VS OPAQUE - You can purchase opaque or clear Check Valves. With a clear valve you can see the spring mechanism to determine if it is clogged with debris or if the spring is weak and won't completely close the valve.

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Step 8

UNION VS NON-UNION - Valve come with and without unions. Unions allow you to remove the valve for cleaning without having to cut the valve out of the plumbing. Some valves can be accessed and repaired through the top of the valve. For these types, the valve body does not need to be removed and is typically installed into the plumbing without unions - commonly referred to as a "slip" connection - pipe "slips" into the valve and is permanently glued.

Step 9

CLEARING DEBRIS - Debris will occasionally get caught in the valve keeping it from closing completely. For instructions on how to clear debris from a typical Spring Flapper Valve, see "How To Clear Debris From a Pool Spring Flapper Valve." For instructions on how to clear debris from a typical Spring Check Valve see "How To Clear Debris From a Pool Spring Valve."

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Step 10

REPAIRING A CHECK VALVE - If the spring mechanism in a Check Valve is weak or broken, you will have to replace it. Unfortunately, not all Check Valve can be repaired. The Spring Check Valves discussed above cannot be opened for they must be replaced. On a Spring Flapper style Check Valve, the Flapper mechanism can be accessed and replaced through the top of the valve. See "How To Repair a Pool Spring Flapper Check Valve". for further instructions.

Step 11

REPLACING A CHECK VALVE - To replace a Spring Check Valve see "How to Replace a Pool Spring Check Valve". To replace a Spring Flapper Check Valve see "How To Replace a Pool Spring Flapper Check Valve".

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 Posted: 1/31/2022 

I have a swing type flap and I have diatomaceous earth flowing back into the pool when equipment is off. should I be using a spring type flapper valve to stop this from happening ?? I have no leaks on the suction side of system and its driving me crazy.tanks

InyoPools Product Specialist  Posted: 2/1/2022 

Regardless of the type of check valve, when the pressure drops, the valve should close, preventing backwash. Have you tried opening the valve to check for the spring or flap seal issues?

Anonymous  Posted: 2/2/2022 

I replaced the swing valve with a spring valve and it solved my problem. Because this valve is horizontal the swing flap did not close completely and thus the earth would drift back to the skimmer. Thanks for your response

 Posted: 4/11/2019 

I have recently installed a Jandy Check Valve 7235. Everything seems to be functioning ok but the door on the valve is not pushed up all the way. Is this normal? It is currently installed on a horizontal line in-front of a 90-degree angle moving the water up to the in-line chlorinator.

InyoPools Product Specialist  Posted: 4/17/2019 

Thank you for contacting Inyo. It is normal for the door not to open all the way.

 Posted: 11/14/2017 

I have a Jandy Check Valve near a chlorinator. Is there a corrosion resistant spring for this? Would a CMP corrosion resistant flapper assembly work in the Jandy casing? Thanks

InyoPools Product Specialist  Posted: 5/10/2017 

Eric - Yes, water is supposed to be running thru the check valve when the pump is on. Make sure the valve is installed with the arrow going in the direction of the water flow. If it is and the valve is older, you may have to replace the inside valve mechanism or the whole valve depending on what valve you have.

 Posted: 5/9/2017 

Is water supposed to be running thru the check valve when the pump and filter is on?

 Posted: 5/2/2017 

Very informative guide on check valves. Thank you.


InyoPools Product Specialist  Posted: 5/16/2016 

Arnolus Koropit - Depends on how mimi your pool is and it you want to clean it manually or automatically. Here's a link to how to assemble a typical above ground cleaner. If your pool is really small, you may want to use a vacuum head on a pole using the pump's vacuum. Pole and vacuum hose are purchased separately. For a small to medium size in-ground pool, you might consider the Pool Cleaner 2 Wheel Cleaner.

 Posted: 5/16/2016 

I needing your help some information how to clean the bottom of mini swimming pool, can you explain how to clean while using/running the pool pump.

Anonymous  Posted: 2/29/2016 

very informative