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Papatrexas, General Contractor
Category: Plumbing
Satisfied Customers: 70
Experience:  I am licensed General & Electrical contractor for more then 35 years with 40 years experience in the construction industry.
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I have Reverse Osmosis Filtration unit. WHER25. The water

Customer Question

I have Reverse Osmosis Filtration unit. WHER25.
The water keeps on backing up and ejecting out of the side port where the air gap is located.
It seems as if the reject water tube -black tube – does not have enough space within the tube for the reject water to drain properly
Submitted: 9 months ago.
Category: Plumbing
Expert:  Papatrexas replied 9 months ago.

Hello My name is and I will be happy to assist you if you still help with your question.

Customer: replied 9 months ago.
What is happening with the water ejecting from the unit? Is it normal to replace or clean the tubes that come with the system? How do I clean the tubes that are part of the WHER25? Can I even order replacement tubes or purchase replacement tubes at Lowes/ Home Depot? Do I have to deal directly with Whirlpool?
Customer: replied 9 months ago.
The tubes I'm referring to are the 3/8" black plastic" , the blue 3/8" parker parflex plastic, and the red 1/4" parker parflex plastic tubing.
Expert:  Papatrexas replied 9 months ago.

Hi the 3/8" & 1/4" plastic tubing is a standard size tubing you can get at any hardware store.

But i don't see why you need to replace the tubing there not suppose to get dirty or a need to get cleaned.

How old is the unit?

Is it new install?

Read this statement and see if it sheds some light and let me know please.


Why is it leaking water up by the faucet through the air bleeding line?


That is the overflow because the drain line connected between the sink-top tap and the p-trap is not draining fast enough. They designed it this way. This is also the water you hear dripping all the time. The drain line works by gravity so make sure it is not kinked or looped so that the water can run downhill to the p-trap

Customer: replied 9 months ago.
The WHER25 install is at least 2 years old. And the unit is at least 2 years old.Now I am completely confused. It makes sense that the bad water drainage from the sink-top tap and the p-trap is not draining fast enough. But there has to be some way to fix it. I watched one video and the technician explained that it is completely possible to have the drain line gunked up. If it is not the gunked up line, then I wouldn't know what else to do.
Expert:  Papatrexas replied 9 months ago.

One thing comes to mined is that the discharge tubing has been pushed too far in and touching the wall on the other side of the ABS drain tube

Can you take a picture of your setup maybe I see something?

Expert:  Papatrexas replied 9 months ago.

I assumed the waste is inserted in to drain and I dint ask if is connected thru the drain adapter if it is thru the adapter I will take the fitting apart and see if is clogged with calcium or something.

I hope this helps.

Expert:  Papatrexas replied 9 months ago.

If you have any additional questions, just let me know and I’ll answer them for you.

Otherwise rate me using the stars at the top of the page.

That’s the only way I get compensated for my time.

Customer: replied 9 days ago.
I learned that there is an attachment on the WHER25 “bad water” drain tube that seats in the drain fitting. The attachment contains a special adapter, which has a cylindrical shape. The cylinder is screwed tight to the drain tube housing, so in investigating the problem the cylinder is the first thing that I checked.
It turns out the cylinder was clogged and would not let the bad water flow from the drainage insertion point all the way to the discharge point.
I cleaned the gunk from the cylinder and then proceeded to check the rest of the system. I was able to replace all the lines which had accumulated sediment in them.
I connected the system back up to the original configuration and I still have water shooting out the air gap hole.
Expert:  Papatrexas replied 9 days ago.

At this point I will disconnect the red and black tubing and check that there clean and read this PDF instruction link

note: if the water discharging from the base of the faucet check this from page 18 of the PDF

NOTE: When the system is first pressurized, water
may ''spurt'' from the faucet air gap hole until air is
expelled from the RO system.

Expert:  Papatrexas replied 9 days ago.

Try this one