What is an RO Flow Restrictor and When to Change?

Just like the name suggested, the RO flow restrictor restricts the flow of the RO reject water. Here the flow restrictor will help in maintaining high pressure just inside the RO membrane. It is done by creating back pressure right on the membrane and controlling the purifier’s recovery ratio. 

Using Flow Restrictor

Now, if the flow restrictor is not used, the high pressure of water coming from the booster pump will flow in an unrestricted way right from the reject outlet of the RO membrane.

Frankly, this will lead to low pressure right inside the RO membrane and won’t work if the pressure present in the RO membrane is high.

Do you know flow restrictors are available in various flow ratings? They are properly sized based on the capacity of the RO membrane.

Here, the flow restrictor’s value would be four times the production rating or even the membrane’s capacity. 

For matching the flow restrictor, one would have to convert the capacity value of the flow restrictor into GPD. Well, this is very simple.

All you would have to do is multiply the flow restrictor capacity into the mL per each minute. It is through the 0.38 for converting it into GPD. 

When To Change Flow Restrictor?

It is recommended to change or replace the flow restrictor every time the RO membrane is replaced. Over time, the RO membrane and filter will get choked, and the same will happen to flow restrictors.

Also, if the new RO membrane is of different capacity, the flow restrictor should be changed as per the capacity of the RO membrane.