When To Install a Check Valve in Your Pool Plumbing

WRITTEN BY:  Inyo Pools

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This guide discusses the function of a pool check valve and when and where to install it in your pool's circulation system.

Step by Step


Step 1

PURPOSE OF A CHECK VALVE - 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. Common uses of a check valve are discussed in the following steps.

Step 2

CHLORINATION - Most pools have an automatic chlorination device like a chlorinator or a salt chlorination generator. The concentrated chlorine level that is discharged from these devices should not flow thru your pool equipment and for this reason the device is installed as the last unit before water is returned to the pool. To prevent water from backing up thru the system after the pump is shut off, a check valve must be installed just before the chlorination device - on the side going to your filter of heater.

Step 3

SOLAR HEATING - Most solar panels are installed on a house's roof 8' above the pump. To capture the sun's heat efficiently the piping in the solar panels must be full of water continuously. Without a check valve to stop backward flow, the water in the piping would be suck back down when the pump is shut off. The check valve should be installed in the pipe leading up to the solar panels.

Step 4

SPA - The level water in your spa is often higher than the water level in your pool. When water to the spa is shut off, the spa water level would drain to the level of the pool water. A check valve is installed to maintain the level of the spa water.

Step 5

WATER FEATURES - Many water features have reservoirs. A check valve is installed in the line to the water feature to keep the reservoir from draining when the pump is shut off.


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InyoPools  Posted: 09/10/2018 16:46 PM  Inyo Product Specialist

Hello Rodney - You can install a check valve after a chlorinator but it won't protect your heater or filter. The purpose of the check valve is to prevent highly concentrated chlorine from flowing back to your equipment.

Rodney  Posted: 09/10/2018 10:34 AM 

Can the check valve be installed after the chlorinator?

Inyopools  Posted: 12/19/2017 13:04 PM  Inyo Product Specialist

Dale - Even though the Salt Chlorine Generator is not producing chlorine when the pump is off, there is a concentrated level of chlorine in the water between the SCG and the returns. When the pump is shut off, there is often a reverse flow of water back into the system. This backflow water after the SCG could damage the equipment before the SCG.

Dale  Posted: 12/13/2017 20:24 PM 

why is a check valve required for a salt cell generator? when power is off to both the pump and salt cell its no longer generating chlorine. i understand the need for an erosion chlorination device where concentrated chlorine can be produced after the system is powered down, but a salt cell doesn't produce chlorine after the power is off. Please advise why additional pressure drop should be added to the plumbing via a check valve, if it doesn't really add value in a salt cell system.

Inyopools  Posted: 05/15/2017 10:38 AM  Inyo Product Specialist

Tom murphy - Yes, a check valve can be mounted in any position. They are operated by water pressure against the flapper of spring.

Tom murphy  Posted: 05/13/2017 10:21 AM 

Can the check valve be mounted in a hormonal position ?