How Does an RO Auto Shut-Off (ASO) Valve Work?
Written by: Gene Fitzgerald // Last Updated: Aug 25, 2023
This page may contain affiliate links. If you buy a product or service through such a link we earn a commission at no extra cost to you. Learn more.
There are so many components in a reverse osmosis system, and you would be forgiven for not being able to memorize them all. Particularly a little guy, like the automatic shut-off valve!
However, this guy plays an important role in ensuring your RO system functions efficiently.
Let’s learn a bit about it!
Contents
show
Key Takeaways
- An RO auto shut-off valve uses a shut-off mechanism to switch the water flow to the RO system on and off, depending on whether or not the reverse osmosis storage tank is empty or full. The mechanism is based on backpressure from said tank.
What Is an RO Auto Shut-Off Valve and How Does It Work?
So, what is an RO auto shut-off valve and how does it work?
The automatic shut-off valve regulates water flow into a reverse osmosis system. It serves two crucial functions: Ensuring minimizing water waste and extending the system’s lifespan.
The automatic shut-off mechanism comprises two chambers and a diaphragm. The diaphragm’s movement within the chambers/housing depends on the pressure difference between the incoming water and the backpressure from the RO storage tank. When the storage tank pressure surpasses two-third the inlet water pressure, the diaphragm pushes up, halting the feed water flow. The flow will only resume once the storage tank pressure decreases due to water withdrawal at the faucet.
Without the automatic shut-off valve, water would continue flowing into a reverse osmosis system, through the pre-filters, passing by the RO membrane, and down the drain – causing wear and tear on the components and wasting purified water once the reserve tank is full.
Benefits: Why Do I Need an ASO Valve in My Reverse Osmosis System?
- It automatically stops unnecessary filtration of water when the storage tank is full.
- Eliminates unnecessary wastewater as the system is not constantly operating.
- It helps keep the pre-filters and RO membrane clear and functioning longer by preventing them from fouling up with too much debris or sediment due to constant filtering.
How to Install an RO Auto Shut-Off Valve
- Switch off the water supply: Before working on your RO system, turn off the water supply and disconnect the power supply if there is one.
- Close the storage tank valve.
- Drain any remaining water from the system.
- Identify the right tubing connections: Ascertain which tubes are associated with the water supply inlet (downstream of any pre-filters) as well as the permeate line. They are typically color-coded.
- Adjust the tubing length: If required, modify the tubing to an appropriate length, ensuring ample slack for the ASO valve without causing tension or kinks that could result in blockages or future problems.
- Attach the water supply inlet and outlet tubes: Place the water supply inlet tube into the ASO valve’s ‘in’ port and connect the water supply outlet tube to the ‘out’ port.
- Secure the filtered water lines: Connect the permeate line to the ASO valve’s ‘permeate in’ port as well as the ‘permeate out’ port. Make sure that the connections are secure.
- Evaluate the system: After ensuring no leaks exist, allow the RO system to run briefly to verify that the ASO valve operates correctly and halts water flow when the storage tank is full.
Further Reading:
Other Commonly Used Valves in Home RO Systems
The other most commonly used valves in a reverse osmosis system are the feedwater and the check valve.
Feedwater Valve
The feedwater valve links the cold-water supply that enters your whole home to your RO system. For whole house systems, this connection is made to the primary water line of the house.
Check Valve
An essential component of an RO system is the check valve. Its purpose is to stop water from flowing back into the RO membrane housing, which could potentially harm or cause the membrane to burst.
If you have any thoughts about the question, how does an RO auto shut-off valve work, please don’t hesitate to leave a comment below!
About the Author Gene Fitzgerald
Information provided on BOS is for educational purposes only. The products and services we review may not be right for your individual circumstances.
We adhere to strict editorial guidelines. Rest assured, the opinions expressed have not been provided, reviewed, or otherwise endorsed by our partners – they are unbiased, independent, and the author’s alone. Our licensed experts fact-check all content for accuracy. It is accurate as of the date posted and to the best of our knowledge.