Flow Restr, Female 350 ml/Min

The TST Water (Aquamor) Flow Restrictor, with a female-threaded connection and a 350 ml/min rating, is a drain-line flow control for residential reverse osmosis systems. By fixing the rate at which reject water flows to the drain, it sets the cross-flow that keeps the RO membrane continuously flushing away contaminants and operating at its proper recovery ratio.

• TST Water flow restrictor, 350 ml/min rating
• Female-threaded connection style
• Controls the RO membrane drain (reject) flow
• Maintains the correct permeate-to-reject ratio
• Helps protect and prolong membrane life
• Compact component for residential RO systems

Why Drain Flow Control Matters

Reverse osmosis works by forcing pressurized water through a semipermeable membrane that allows clean water to pass while rejecting dissolved solids and other contaminants. For the membrane to keep working well, a continuous portion of the feed water must sweep across its surface and carry those rejected solids out to the drain, rather than letting them build up and foul the membrane. The flow restrictor is the component that sets this sweep, or cross-flow, rate. Get it right and the membrane stays clean and produces water efficiently; too little drain flow causes rapid fouling and shortens membrane life, while too much drain flow simply wastes water and reduces the system's production efficiency.

This 350 ml/min version uses a female-threaded connection and is matched to membranes whose production calls for that particular drain rate. Because the restrictor must correspond to the membrane it serves, it is important to keep the two matched whenever you service or upgrade the system. When you replace an RO membrane with one of a different production capacity, the flow restrictor should be changed to suit the new membrane so the recovery ratio remains correct. Before installing, confirm that the 350 ml/min rating aligns with your membrane's specifications, verify that the female threads match your system's fittings, depressurize the system first, and install the restrictor in the correct orientation on the drain line according to the indicated flow direction. Keeping the flow restrictor matched to the membrane is a small detail that has an outsized effect on water efficiency and membrane longevity, making this an important part to check whenever you service or upgrade your reverse osmosis system.