How to Install a Reverse Osmosis Float Valve - BRStv How-To
All you need to install a Float Valve is a 1/2" drill bit and an adjustable wrench. Just drill the hole where you want to install the float valve, we usually recommend a couple of inches from the top of the reservoir. Then remove the compression nut, ferrule, spacer, and retaining nut from the threaded portion of the float valve. Slip the threaded end of the valve through the hole making sure that the gasket is on the inside (float side) of the reservoir. Then install the retaining nut, you can use an adjustable wrench to tighten the nut but do not overtighten. That will mount the float valve to the reservoir, and you can now connect your water supply to the valve.
With the end of your RO tubing in hand, slip the compression nut on the tubing then the ferrule, and finally the spacer. Push the tubing into the stem of the float valve until the tubing comes to a complete stop, then slide the compression nut up to the threads capturing the ferrule and spacer. The compression nut should be hand tight; excessive tightening can cause damage or leaks.
With two different styles of float valves, adjustable or non-adjustable, we typically recommend the non-adjustable models since it is one less point of failure. However for applications where the exact water level is not known yet, or it may need to vary by an inch or two, the adjustable model works great!