by Sean Griffin, September 24, 2009
The push-pull valve is the most simplistic valve to use when backwashing is required. It has only two settings, filter or backwash. The advantage to having a push pull valve as opposed to a multi position valve is that there are fewer components and therefore fewer parts that can malfunction and need replacing. The push pull valve (also called a Slide Valve) will also allow for a slightly higher flowrate as well, as compared to multiport valves. Older bronze style push pull valves more than twenty years old are still being used today in the backyard of many pool owners. Proper use and proper maintenance will ensure the longevity of your push pull backwash valve.
The push pull valve typically consists of a piston with disks, also called a plunger, that direct the water coming in and leaving the valve. The piston is raised or lowered to achieve the desired operation. The up and the down position vary between different styles of filters, but always provide two options: Filter or Backwash. The piston disks are encased in an o-ring that creates a positive seal. A set of o-rings is also located at the cap on the stem to make sure valve body is water tight.
The most common replacement parts for your push pull valve are the plunger o-rings. Go-Kits are convenient packs that would include all of these o-rings and a small amount of a silicone based lubricant for installing. Replacing the plunger o-rings is a simple matter of removing the plunger, swapping rings and lubricating.
Whenever changing positions on your valve make sure the pumps are off and not set to come on. Lubricating the internal o-rings will increase life of the o-rings and make movement easier. An uncommon issue that I have dealt with is the individual disks breaking off and becoming lodged in the housing. I used a combination of hand tools to pry and suction from a shop vac to remove. When you manage to remove broken disk(s) you can then replace the entire stem. The only reason you would need an entire replacement valve is if the housing has cracked. I do also recommend upgrading to ABS plastic if you have one of the older bronze valves used on Anthony pools, among others.
When winterizing your pool make sure all water is removed from your equipment including your valve. The Push pull valve does not have a separate drain valve and should be vertical allowing it to be self draining.
So, other than using some magic lube twice annually on the piston o-rings, there really is no maintenance needed on a push pull valve. Just remember to shut the pump off before moving the valve position and drain the valve body if you winterize your pool.