A Flow Restrictor protects an RO Membrane by maintaining back pressure on the concentrate line to hold the designed waste-to-permeate ratio, stabilize membrane hydration, and limit fouling and scaling in typical residential and light commercial systems at AXEON SUPPLY
What does a Flow Restrictor do in RO?
A Flow Restrictor maintains back pressure on the concentrate line to hold a designed concentrate‑to‑permeate ratio, which keeps the RO Membrane hydrated, limits fouling, and stabilizes long‑term performance in service environments. In residential and light commercial installations, capillary Flow Restrictors install in the 1/4 inch OD waste (brine) line and regulate brine discharge so the RO Membrane operates within intended GPD and pressure conditions, supporting predictable recovery and permeate quality without over‑wasting or starving the element. AXEON SUPPLY’s component context emphasizes correct restrictor sizing and proper placement to sustain stable crossflow and pressure balance across RO Membranes in typical U.S. applications and service routines.
How Flow Restrictors protect RO Membranes (mechanisms)
Proper flow restrictors protect RO Membranes by maintaining the waste-to-permeate ratio, sustaining boundary layer control at the membrane surface, and reducing premature scaling, which extends service intervals in typical residential and light commercial systems.
- Maintains target waste ratio to keep salts flushed from the membrane surface, supporting continuous crossflow that limits deposit formation on the RO Membrane.
- Supports stable permeate production within the RO Membrane’s GPD rating, preventing starvation at low pressure and overspin at excessive discharge through the concentrate line.
- Preserves element integrity by preventing uncontrolled brine dumping that would collapse operating pressure and disturb membrane hydration equilibrium during normal duty cycles.
These mechanisms align with capillary Flow Restrictors installed on 1/4 inch OD waste lines under AXEON SUPPLY’s component context and service practices.
What is the recommended waste ratio with a Flow Restrictor?
Residential RO systems typically run a several‑to‑one concentrate‑to‑permeate ratio to maintain cleaning crossflow without excessive waste, and the specific ratio depends on feed TDS, available pressure, water temperature, and the RO Membrane’s GPD rating. Commission standards should define the design ratio in system documentation, label the expected waste‑to‑permeate target near the concentrate line, and record the verified ratio at startup for service reference. Service teams can validate the ratio with a timed permeate vs. waste catch test and adjust Flow Restrictor selection only within the intended membrane rating class to preserve stable operation and predictable maintenance intervals.
Which Flow Restrictor matches each RO Membrane rating?
Match the Flow Restrictor’s GPD to the RO Membrane’s rating class to preserve the intended waste‑to‑permeate ratio and stable operating pressure across the element.
- 12 GPD (Red) – 200986; capillary insert for 1/4 inch OD waste line; Delrin; quick‑connect/compression compatible.
- 18 GPD (Brown) – 200987; capillary insert for 1/4 inch OD waste line; Delrin; quick‑connect/compression compatible.
- 25 GPD (Black) – 200988; capillary insert for 1/4 inch OD waste line; Delrin; quick‑connect/compression compatible.
- 35 GPD (Yellow) – 200989; capillary insert for 1/4 inch OD waste line; Delrin; quick‑connect/compression compatible.
- 50 GPD (Green) – 200990; capillary insert for 1/4 inch OD waste line; Delrin; quick‑connect/compression compatible.
- 75 GPD (Blue) – 200991; capillary insert for 1/4 inch OD waste line; Delrin; quick‑connect/compression compatible.
- 100 GPD (White) – 200992; capillary insert for 1/4 inch OD waste line; Delrin; quick‑connect/compression compatible.
- 150 GPD (Grey) – 200993; capillary insert for 1/4 inch OD waste line; Delrin; quick‑connect/compression compatible.
- 200 GPD (Orange) – 210184; capillary insert for 1/4 inch OD waste line; Delrin; quick‑connect/compression compatible.
How do Flow Restrictors for RO Membranes install?
Insert the capillary Flow Restrictor into the 1/4 inch OD waste/concentrate line using compatible quick‑connect or compression fittings, and match the color and part number to the RO Membrane’s GPD rating for correct restriction.
- The capillary length determines restriction; shorter lengths increase flow, longer lengths decrease flow within the drain line.
- Verify the tubing is the brine/rinse outlet from the membrane housing before insertion, push the tube fully into the fitting, gently pull back to confirm engagement, and check all joints for leak‑free seating after repressurizing the system.
Symptoms of an incorrect Flow Restrictor
Symptoms of a mismatched Flow Restrictor include low permeate output, excessive waste discharge, unstable permeate TDS, and frequent RO Membrane fouling driven by improper crossflow and pressure balance across the element.
- Too small restrictor: line pressure spikes at the membrane, reduced brine flushing, rapid scale deposition, and shorter service intervals for the RO Membrane under typical residential/light commercial duty.
- Too large restrictor: excessive brine waste rate, depressed membrane inlet pressure, low permeate production, and difficulty reaching expected recovery within the membrane’s GPD rating class.
Technicians can confirm mismatch by performing a 60‑second catch test on permeate and concentrate, comparing the observed ratio to commissioning targets before re‑selecting a restrictor within the membrane’s rating class for AXEON SUPPLY systems.
How to verify Flow Restrictor sizing in the field
Check the RO Membrane’s GPD rating, verify available feed pressure, and time permeate vs. concentrate volumes to confirm the observed waste ratio matches the design target for the installed Flow Restrictor.
- Record the membrane GPD from the element label and match it to the Flow Restrictor’s part number and color code before testing (e.g., 50 GPD → 200990 Green; 75 GPD → 200991 Blue; 100 GPD → 200992 White).
- Place measured containers on permeate and concentrate lines for 60 seconds, compute concentrate‑to‑permeate ratio, and compare to commissioning documentation; adjust only by selecting a restrictor within the membrane’s rating class to maintain stable operation and predictable maintenance intervals.
Material and design details that support protection
Delrin construction, anti‑clog design features, and compatibility with quick‑connect and compression fittings help maintain consistent restriction and reduce unplanned service interruptions for RO Membranes in typical residential installations. The 1/4 inch OD tubing fitment standardizes placement on the waste line, while service‑friendly capillary insertion and removal simplify maintenance cycles and support predictable field replacement aligned to membrane GPD classes and color‑coded parts.
Flow Restrictors in Water Treatment: where they fit
Flow Restrictors in AXEON SUPPLY’s water treatment portfolio are standard components that help enable reliable RO Membrane performance for residential and commercial applications across typical U.S. use cases, supporting stable operation and predictable maintenance schedules. AXEON SUPPLY supports integrators and resellers with components, parts, accessories, dependable fulfillment, and technical guidance.