An automatic multiport valve may significantly reduce the amount of time you spend on maintenance while also improving the overall performance of your sand or diatomaceous earth (D.E.) filtering system. Despite this, the multiport valve (MPV) might appear to be a bit daunting at first sight. But fortunately, understanding how to use a multiport valve is easy to learn.
As long as you understand the purpose of each setting, MPVs make pool maintenance way easier. In this post, we’ll go over the common functions of a multiport valve as well as the situations in which swimming pool owners would wish to use them.
How Does a Multiport Valve Work?
A multiport valve is controlled by an electric solenoid or a cartridge (or both), depending on the model. The pool operator can change the settings of the multiport valve by moving the lever back and forth.
The multiport valve has five ports that allow water to enter one port and exit through another. Four of these ports are used to control flow into or out of the filter tank. The fifth is connected to either a skimmer or an optional cleaning head port connected to your robotic pool cleaner.
One step remains constant in whatever setting you wish to use: switch off the pump before adjusting the valve setting.
Skipping this step endangers the entire filtration system. In addition, the increased pressure can destroy O-rings, rubber diverter gaskets, and other internal components. Failure to do so can also create danger throughout the lines, damaging not only equipment but people nearby.
Multiport Valve Settings
Most multiport valve settings have eight settings to control the pool’s filter’s functionality.
Filter Setting
The FILTER position is the default setting for your filter valve, and it will remain in this position for the majority of the time. When the filter tank is in this position, water is forced into the tank, passes through the filter media, exits the tank, and is returned to the swimming pool.
When vacuuming the pool, another common application for the FILTER setting is to remove debris from the pool.
Waste Setting
On a multiport valve, the WASTE setting is one of two ‘bypass’ settings that you can select. WASTE redirects the water that has been pumped from the pool to the backwash line or hose.
There are two situations in which you might want to use the WASTE option. The first is to get the water level down. The second situation is when you need to vacuum up particles but don’t want the material to pass through the filter media itself.
Winter Setting
The WINTER setting is designed to provide space for droplets. In case the weather drops to freezing levels, the droplets of water trapped in the MPV have space to expand by sitting above the grooves that otherwise allow the entrance and exit of the flowing water.
The valve could be destroyed without this additional space when frozen ice droplets shatter or dislodge critical internal components.
Winter “setting” is especially critical in areas where the temperature drops to freezing levels. While the multiport valve is not the most expensive pool component, you may not realize it is broken until it begins creating more severe problems the following season.
Closed Setting
The CLOSED position doesn’t allow backwashing or circulation, which allows you to clean the filter tank without any wastewater going into the pool. This setting is often used when taking the filter media out for cleaning or servicing.
Running the filter or pump in a closed position might create major issues due to the pressure buildup that occurs when there is nowhere for the water to go. This can cause catastrophic failure requiring extensive repair, not to mention creating a dangerous situation everyone closes when something ruptures.
Skimmer Setting
The SKIMMER setting diverts water normally pumped into the filter system and instead sends it directly to the pool’s skimmer. This is a handy setting for those who wish to manually drain their pool via the attached garden hose and those who wish to set up robotic cleaning systems.
Backwash Setting
The BACKWASH setting is used to clean the filter by draining away dirt and debris collected in the filter media and directing it through to the backwash line.
Recirculate Setting
RECIRCULATE is the multiport valve’s second ‘bypass’ setting. The pump draws water in and then returns it directly to the pool, bypassing the filter entirely. The RECIRCULATE option is most useful when your filter has a problem and needs fixing. This will keep your water moving and prevent stagnation until your filter works again.
Rinse Setting
The RINSE setting flushes and cleanses any leftover dust particles from the sand bed, preventing dust from blowing back into your pool. Rinsing a sand filter bed takes about 15-20 seconds.
Bottom Line
“Always remember to turn off your pump before attempting to operate the Multiport Valve. Changing the position of the valve while the pump is running can cause damage to the valve and develop pressure inside the system. This can damage your pump and lead to major repairs and possibly cause an explosion. Nobody wants that.”
Dr. Pool, Doctorate in Chemistry, Swimming Pool Enthusiast\
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