Slide Valves
Slide valves are an alternative to MPV Valves and mount on the side of DE or sand filters. Slide valves have two functions - FILTER or BACKWASH. Slide valves are simpler then MPV valves, have less parts, offer higher flow rates, and less restrictions.
Many people find the slider valve troublesome and switch to a MPV valve.
Slide Valve Modes
Filter
FILTER is the normal setting for the water to flow through the DE or sand.
Backwash
You pull the slide valve up to backwash the filter and flow the dirt and pool water through the waste line.
Troubleshooting
DE returning to the pool as it is being added
If the valve shaft O rings are worn/missing that will happen.[1]
If an older Pentair with the stainless-steel shaft, the "pucks" holding the O rings are held in place by small "e" clips that break/corrode/disappear. The "puck" moves and the same thing will happen.
If your slide valve looks exactly like this, there are no O rings on the pucks. You will definitely have DE return to the pool. Those O rings need silicone lube on them as well.[2]
Sticking slider
75200 Zer0 Pool and Spa Lubricant can be used to release a stuck slider. Pull the valve up as much as you can and squirt the lube very liberally around the O ring. Work the slider up and down and turning it as much as you can to get the lube down into the slider.
This You Tube Video shows how the lube can be used.
What can happen is the orings swell. Then no amount of lube will do it. Use steady constant force. NO shock force to the plastic, it will break. If you get it out and are going to keep, REPLACE the orings every year. They are cheap, and less time consuming.
Repairs
- Slider valves often need their O rings replaced.
- If the slider valve starts getting difficult to pull up you should replace the O rings before it sticks on you.
