Description
The RO Flow Restrictor is a small inline component on the drain (concentrate) line of a reverse osmosis system. It limits how much water flows to drain, which keeps pressure on the membrane so it can push water through and reject salts. Without the right restrictor, either too much water goes to drain and the membrane produces little purified water, or too little goes to drain and the membrane scales up quickly.
Why matching matters
Each membrane rating needs a matching restrictor. A 75 GPD membrane typically uses a 300 ml/min restrictor, while 50 GPD uses around 300 ml/min or less and higher-flow membranes need larger values. If you upgrade your membrane, you should change the RO Flow Restrictor too. A wrong restrictor is one of the most common reasons for poor RO performance we see in homes in Muscat.
Signs of a wrong or blocked restrictor
- Very little or no water going to drain (blocked restrictor)
- Constant heavy flow to drain and slow tank filling (restrictor too large or missing)
- Rapidly rising TDS in RO water
- Automatic shut-off valve not closing
Specifications
| Type | Inline capillary or orifice restrictor |
| Connections | 1/4 inch push-fit or tube insert |
| Common ratings | 300, 420, 550, 800 ml/min and higher |
| Matched membranes | 50 to 400 GPD (check chart) |
Ratings and membrane matching vary by manufacturer; we confirm the right value for your system.
Installation
The restrictor goes on the drain line from the membrane housing, before the drain saddle. Inline types push onto 1/4 inch tubing; insert types sit inside the tubing. Flush the system after fitting and check drain flow with a measuring jug. See related RO spare parts and RO membranes. For background on recovery, see Wikipedia.
Frequently asked questions
Can I remove the restrictor to save water? No. Without it the membrane will not work properly.
How do I know which one I have? The value is usually printed on the body. Send us a photo if not.
Why buy the RO Flow Restrictor from Farz Water?
Farz Water is a water treatment supplier based in Muscat, serving homes, businesses and projects across the Sultanate of Oman. When you choose the RO Flow Restrictor from us, you get more than a product in a box. Our team checks your water and site conditions first, so the equipment you buy matches your actual needs instead of a generic catalogue size. We explain the options honestly, including when a simpler or lower-cost solution will do the job.
We stock common spares and consumables in Muscat, so filters, lamps, membranes and fittings are available when you need them. Our technicians install and commission equipment, show you how to operate it, and return for scheduled service if you choose an annual maintenance plan. If anything is not working as expected, you can reach us directly by phone or WhatsApp and speak to someone who knows your system.
Order an RO Flow Restrictor in Oman
Farz Water stocks RO spares in Muscat. Contact us or call / WhatsApp +968 9455 4533.
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