What is the perfect water pressure for my RO?

Most revers osmosis membranes are designed to work with 60 PSI or higher water pressure, where they are tested to yield a stable rejection rate of at least 97.5%. If the water pressure feeding an RO system is less than that, the system will produce less water and at a lower quality. Additionally, production is reduced whenever the water temperature is below 77 °F.

What if I connect my ice maker?

RO water will produce cleaner ice cubes because of the purity of frozen water. So, connecting your RO to the ice maker makes a lot of sense. However, new ice makers require 30-40 PSI incoming water pressure to function properly. You may not have enough pressure at the pressurized water tank since your RO cuts the line pressure by 30-35%.

How can I increase water pressure?

We will discuss several ways to boost the pressure coming out from your cold-water line to run the RO.

Permeate pump

Permeate pumps use the energy of drain water flow from reverse osmosis system as leverage to push the purified water into the holding tank. Aquatec, the manufacturer of ERP-1000 permeate pump states that these pumps dramatically improve the efficiency of reverse osmosis water (RO) production, reducing wastewater by up to 80%. Permeate pumps can easily be retrofitted to upgrade existing RO systems.

 WECO Permeate Pump Installation Diagram

Electric booster pump design 1

An electric booster pump such as Aquatec CDP-6800 can very efficienty boost the line pressure up to 80 PSI. This simple low-cost setup is the most commonly used design in residential reverse osmosis industry. A differential pressure controlled automatic shut off device (ASO valve) and a high-pressure switch controlls the pump and water flow into the membrane. When the tank pressure gets up to 60% of the incoming pressure the valve internally closes off the inlet. This will build up pressure on the high-pressure switch.

ELCON-56 kit includes the ASO valve, pump, transformer and a high-pressure switch.

 WECO Booster Pump Installation Diagram 1

Electric booster pump design 2

Most commercial reverse osmosis systems and high-end residential ro systems use the following design. Booster pump here is controlled by two pressure switches. A low-pressure switch at the inlet (activated or conducting current around 5 PSI) makes sure the pump will not run dry. A high-pressure switch (deactivated at 40, 60 or 80 PSI) cuts off power to the pump when the pressurized water storage tank has reached the capacity. A solenoid valve stops water supply to the membrane when the pump is off, preventing water running down the drain continuously. Wiring and plumbing diagrams below.

ELCON-24 kit includes the solenoid, pump, transformer and high/low pressure switches.

WECO Booster Pump Installation Diagram 2