Auto shut off valves use a small amount of pressure created by your float valve to shut off the water supply to your RO membrane. This is simple instructions on how to install one into your RO system.

First note the top and bottom of the shut off valve, the bottom has the screws. Also note the in/out marks pressed into the top of the shut off valve.

The Blue line goes leaves the RO membrane as fully filtered water, goes into the "in" on the bottom of the valve and then leaves through the "out "on the bottom. This is your filtered water that either goes to your DI resin or to your storage tank.

The Red line leaves your last carbon block, enters the "in" on the top of the valve, then leaves through the "out" on the top of the valve and then enters the RO unit.

To function properly the unit also requires a check valve on the filtered water end of the RO membrane. Many RO systems come with the check valve built in. You will need to check yours to see if you have one. It is inside the 90 degree hose fitting and pictured below. . If your system doesn't have one you can purchase one from us for a few bucks. They come in two different styles. Inside a 90 degree fitting or inline with quick connect fittings. Both work equally well, the inline unit is easier to install and replace.