RO/DI Unit Producing Water too Fast

InLimbo87 · 06/09/2010, 07:14 AM

My RO/DI unit is producing too much water. It is a 75 GPD unit and instead of dripping the "clean water" (as usual) it has been streaming much faster. I just replaced the RO membrane and DI resin, and the other filters were replaced just months ago. The waste to clean water ratio appears to be about 2:1, and the unit is putting out about 150 GPD through the clean tube.

What could be causing this? I had a cheap-o TDS meter, but it broke on me recently so I have no way of testing the TDS.

Thanks in advance for any help.

poolkeeper1 · 06/09/2010, 07:45 AM

Did you lose you flow restrictor possibly? When you changed the membrane that would cause the issue you are having.
Bill

fsn77 · 06/09/2010, 09:07 AM

I'm pretty sure I've heard this can happen if the RO membrane isn't seated properly in its housing. You may want to double check it just in case.

jchase1970 · 06/09/2010, 10:06 AM

check your ro membrane to make sure it is seated all the way, I've had similar thing happen.

davewbush · 06/09/2010, 10:51 AM

^^^ Same problem too. I had the membrain in backwords.

Buckeye Hydro · 06/12/2010, 05:32 AM

There are two "exit" ports from the RO membrane housing. Water can go out the waste water tube, or out the purified water tube. Flow in the waste water tube is restricted by a partial plug (a.k.a. the flow restrictor). Flow out of the purified water port is retricted by the RO membrane. So if you see too much flow coming out of the purified water port:
1) membrane may be damaged by exposure to chlorine (unlikely in your case as it is brand new)
2) membrane may not be fully seated - this allows waste water to flow out of the purified water port (I suspect this is your issue). If this is the case, use your tds meter to check the RO water and you'll see the TDS level is much higher than it should be.
3) you may have an internal crack in the RO membrane housing (this is relatively uncommon).

Russ @
Buckeye Field Supply

06/09/2010, 07:14 AM	#1
InLimbo87 Registered Member Join Date: Jun 2006 Location: Central FL Posts: 3,197	RO/DI Unit Producing Water too Fast My RO/DI unit is producing too much water. It is a 75 GPD unit and instead of dripping the "clean water" (as usual) it has been streaming much faster. I just replaced the RO membrane and DI resin, and the other filters were replaced just months ago. The waste to clean water ratio appears to be about 2:1, and the unit is putting out about 150 GPD through the clean tube. What could be causing this? I had a cheap-o TDS meter, but it broke on me recently so I have no way of testing the TDS. Thanks in advance for any help. __________________ We are forever responsible for that which we tame... Current Tank Info: 90 gallon

06/09/2010, 10:06 AM	#4
jchase1970 Registered Member Join Date: Nov 2009 Location: Newburgh, Indiana Posts: 409	check your ro membrane to make sure it is seated all the way, I've had similar thing happen. __________________ Tri-State Reef Club Serving the Indiana,Kentucky,Illinois Tri state area.

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06/09/2010, 07:45 AM	#2
poolkeeper1 Moved On Join Date: Apr 2007 Location: Spring Hill, TN Posts: 4,674	Did you lose you flow restrictor possibly? When you changed the membrane that would cause the issue you are having. Bill

06/09/2010, 09:07 AM	#3
fsn77 Registered Member Join Date: Mar 2006 Location: SC Posts: 777	I'm pretty sure I've heard this can happen if the RO membrane isn't seated properly in its housing. You may want to double check it just in case.

06/09/2010, 10:51 AM	#5
davewbush ... Join Date: Feb 2009 Location: California Posts: 739	^^^ Same problem too. I had the membrain in backwords.

06/12/2010, 05:32 AM	#6
Buckeye Hydro .Registered Member Join Date: Sep 2006 Location: Cincinnati, Ohio Posts: 4,857	There are two "exit" ports from the RO membrane housing. Water can go out the waste water tube, or out the purified water tube. Flow in the waste water tube is restricted by a partial plug (a.k.a. the flow restrictor). Flow out of the purified water port is retricted by the RO membrane. So if you see too much flow coming out of the purified water port: 1) membrane may be damaged by exposure to chlorine (unlikely in your case as it is brand new) 2) membrane may not be fully seated - this allows waste water to flow out of the purified water port (I suspect this is your issue). If this is the case, use your tds meter to check the RO water and you'll see the TDS level is much higher than it should be. 3) you may have an internal crack in the RO membrane housing (this is relatively uncommon). Russ @ Buckeye Field Supply