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Reverse Osmosis Troubleshooting - Water Continuously Flows to Drain

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Summary

If you're experiencing a problem with water continuously flowing down the drain from your reverse osmosis water treatment system, then here are some troubleshooting tips!

 

Video Transcript

Gary The Water Guy:
Hi, I'm Gary The Water Guy, and I own the Water Filter e-store and The Water Store, Midland Ontario.


Gary The Water Guy:
Today, we're talking about troubleshooting reverse osmosis drinking water systems, specifically that they never shut off, in other words water keeps flowing to drain. That isn't normal and that needs to be addressed.


Gary The Water Guy:
So if you're not sure how a reverse osmosis system works it'd probably be best at this point to review my video How Reverse Osmosis Drinking Water System Works to understand the different components. But basically what happens is water flows into the system and filters it, and through this ASO, automatic shutoff, and a check valve inside here, that's what monitors the flow, and when the system is full, when it's getting back pressure from the tank, then it shuts itself off because now it's full, and that's how it's supposed to work. But if there's something wrong with either the ASO or the check valve then water could continuously flow to drain.


Gary The Water Guy:
So let's test that out. Now before we go any further I should also mention that you need at least 40 PSI coming from your pump or municipal water supply for this check valve to shut off, and the membrane has to be in good condition. So if you haven't replaced your membrane for many years before you go any further that would probably be a good step to take right now, is replace that membrane so that it's working properly.


Gary The Water Guy:
Okay. So then going on from there, now what we need to do is do a test run. To test the system what you need to do is you need to start with a full tank and then draw two or three glasses of water from the faucet. Once you've done that the system will start refilling. So after you've drawn the two or three glasses shut off the ball valve, and that simulates the tank being full. Now wait three to five minutes. Within that time the water should shut off. If it does shut off then the ASO, the check valve, the whole system is working correctly. Maybe you thought there was water continuously running to drain, but maybe that was just while it was refilling the tank, which is a hundred percent normal.


Gary The Water Guy:
If however water did continue to flow to drain then either the check valve or the ASO is broken and we need to find out which one. So for this next test you need to make sure that again there's lots of water in the tank and that the tank valve is now open.


Gary The Water Guy:
So now what you need to do is you need to shut off the water flowing to the reverse osmosis system. So you'll either have a shutoff that looks something like this, you turn it clockwise until you can't turn it anymore, that shuts off the flow. Or if you have a ball valve shut off like this one here, the on position would be in this direction with the handle facing the direction of flow, and at this point you'd want to turn it off, okay?


Gary The Water Guy:
So now what you do is pull the drain line. It connects to the drain saddle saddle like this, and you want to pull the drain line off and the drain line is black, okay, or you can listen to it if you can hear the water flowing. And at this point listen to it and see if the water is still flowing.


Gary The Water Guy:
If the water is still flowing with the water shut off then what's happening is the water's coming from the tank and it's flowing through the check valve, and this check valve here needs to be replaced.


Gary The Water Guy:
If however, there is no water flowing at this point that means the check valve is working fine, it's the ASO that needs to be replaced. Now when you replace the ASO be very careful that you replace the hoses in exactly the same order as they are here for it to work properly. And that's it.


Gary The Water Guy:
If you like what you saw today please click the subscribe button, that's where you'll be notified of all the new videos as they become available on our channel. Or if you'd like some more information you can go to our website at thewaterfilterestore.com or thewaterstoremidland.com.

And again, I'm Gary The Water Guy from The Water Store in Midland, Ontario. Thanks for watching.

A common concern with a Reverse Osmosis drinking water system is water continuously running to drain. Since the Reverse Osmosis drinking water system (RO) flushes it's waste water while it is filling the tank, water running to drain during production is normal but after 3 or 4 hours of zero water usage there should be zero water running to the drain.

There is an ASO or Automatic Shut Off valve which in conjunction with the check valve shuts off the water when the tank is full. This valve requires a minimum of 40 psi of pressure to shut off the flow. In rare cases where the membrane becomes extremely fouled this can also cause water to continuously flow to drain so if you haven't changed your membrane for several years now is the time before proceeding.

A couple of tests need to be completed to check the system and see if the ASO or the check valve is defective:

1) First, starting with a full tank, draw 2-3 glasses of water from the faucet, the RO will start making water to top off the tank.

2) Turn OFF the ball valve from the tank by turning the handle 90 degrees, which simulates a "tank full" condition. If your RO feeds a fridge, turn off that line too.

3) Wait for 3- 5 minutes, then check to see if the drain water stops running by listening or actually removing the drain line to observe, if the water has shut off both the ASO and Check valve are working properly.

4) If water continues to run to the drain then either the Check Valve and/or the ASO valve is defective.

5) Be sure that the tank is full or close to it and remove the drain line from the drain saddle so you can check the flow.

6) Turn OFF the Cold feed water supply and open the tank valve.

7) Check the drain line, if water flows then this water is coming from the storage tank which means the Check Valve is broken. If no water drains out from the black line this means the ASO is defective and needs to be replaced.




 

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