RO/DI question about reverse flow

Radicaljbr · 12/14/2007, 03:20 PM

I have a RO/DI unit.

There are two outlets. One for RO only and one for RO/DI. I have my RO hooked up to my ice maker and a faucet for drinking. There is also a bladder storage tank for holding water on this line.

My RO/DI is of course hooked up to my tank.

I have noticed that when I am filling buckets or tanks up with my RO/DI line, it bleeds my RO tank. So I guess I am actully filling my tank up with RO water.

Am I doing something wrong? Why would it reverse my flow and take RO water and go into the RO/DI line?

Should it be doing this?

TammyLiz · 12/14/2007, 03:35 PM

I don't know anything about your model but deionization is a final step added onto reverse osmosis filtration in order to further remove impurities that remained in the RO water, so it would make sense that it would be using the RO water

Radicaljbr · 12/14/2007, 04:48 PM

Quote:

Originally posted by TammyLiz
I don't know anything about your model but deionization is a final step added onto reverse osmosis filtration in order to further remove impurities that remained in the RO water, so it would make sense that it would be using the RO water

Okay, I must have been drunk when I wrote this. For some reason, I was thinking that the water coming through my RODI line from my RO tank was still just RO. I just did not think for a second that it still had to go through the DI filter to come out of that line.

Sorry for the brain fart

jdieck · 12/14/2007, 05:01 PM

Quote:

Originally posted by Radicaljbr
Okay, I must have been drunk when I wrote this. For some reason, I was thinking that the water coming through my RODI line from my RO tank was still just RO. I just did not think for a second that it still had to go through the DI filter to come out of that line.

Sorry for the brain fart

In any case you do not wantyour RO tank to empty and leave you without drinking water when you are using your RO/DI. You need to install a check valve that will prevent the back flow.

Look at the installation diagram on the right:

Radicaljbr · 12/14/2007, 05:22 PM

Perfect, now where can I find one?

AZDesertRat · 12/14/2007, 05:23 PM

It depends on how long you want to wait to make DI water. I use my pressure tank to pressurize the DI so I can make water faster, I don't have time to wait all day to make 20 gallons of DI. My time is worth more than that. I would not worry about it, with a small pressure tank you can just about fill a 5G bucket of jug in one shot without waiting. I went an extra step and at one time had two 5G pressure tanks but that still wasn't enough so I now have a14G pressure tank and can fill three 5G jugs in a very short time.

Radicaljbr · 12/14/2007, 05:24 PM

I see you put one on the drain as well. Is that important? I do not think that my unit has reversed that line but you have me thinking.

Radicaljbr · 12/14/2007, 05:26 PM

Quote:

Originally posted by AZDesertRat
It depends on how long you want to wait to make DI water. I use my pressure tank to pressurize the DI so I can make water faster, I don't have time to wait all day to make 20 gallons of DI. My time is worth more than that. I would not worry about it, with a small pressure tank you can just about fill a 5G bucket of jug in one shot without waiting. I went an extra step and at one time had two 5G pressure tanks but that still wasn't enough so I now have a14G pressure tank and can fill three 5G jugs in a very short time.

Good point!!

AZDesertRat · 12/14/2007, 05:30 PM

The waste line(drain) has a flow restrictor not a check valve.

jdieck · 12/14/2007, 07:32 PM

Quote:

Originally posted by Radicaljbr
Perfect, now where can I find one?

http://www.thefilterguys.biz/fittings.htm

Scroll down to 1/4" x 1/4" quick fitting in line check valve $8.00

Radicaljbr · 12/14/2007, 09:06 PM

Quote:

Originally posted by AZDesertRat
The waste line(drain) has a flow restrictor not a check valve.

the diagram shows both on the drain

Radicaljbr · 12/14/2007, 09:08 PM

Quote:

Originally posted by jdieck
http://www.thefilterguys.biz/fittings.htm

Scroll down to 1/4" x 1/4" quick fitting in line check valve $8.00

Thanks again!!

TammyLiz · 12/14/2007, 09:43 PM

jdieck, I love your sig line! Cracks me up.

Probably most people feel like that all the time. Or, at least I like to think so, since I do.

jdieck · 12/14/2007, 10:34 PM

Quote:

Originally posted by TammyLiz
jdieck, I love your sig line! Cracks me up.

Probably most people feel like that all the time. Or, at least I like to think so, since I do.

Where did I leave the keys?

Have you seen my cup of coffee... Where the heck did I put it?

Now, what was I looking for in here?

Sound familiar?

Radicaljbr · 12/14/2007, 11:06 PM

Sounds like something House would say.

TammyLiz · 12/14/2007, 11:16 PM

Quote:

Originally posted by jdieck
Where did I leave the keys?

Have you seen my cup of coffee... Where the heck did I put it?

Now, what was I looking for in here?

Sound familiar?

Too familiar!

jdieck · 12/15/2007, 12:23 AM

AZDesertRat · 12/15/2007, 10:49 AM

Show me a check valve on the drain line??? It says "flow restrictor" and "to drain", thats it. Where you see a check valve is the other line from the RO membrane which is on a different flow path or circuit. Note that membrane housings have 2 entrances/exits on one end and 1 on the other. On the end with two fittings the one towards the outside edge is the waste line and the one towards the center is the product or good line out.

Radicaljbr · 12/15/2007, 11:19 AM

I am looking at the right picture and there is only one line that says drain. Right next to that is the flow restrictor. If you keep following this line to the left the very next thing it says check valve and there is a break in the line.

I do not think I am readling this wrong. Anyone else have a comment? Or is it just me reading this thing wrong?

AZDesertRat · 12/15/2007, 11:39 AM

To drain means just that. You plumb that drain line to the sink drain. It does not connect to anything else.

chris4869 · 12/15/2007, 11:54 AM

I think you are misinterpreting the picture. The break, as you are referring to, is actually the exit waste water pipeline FROM the membrane housing. You connect the drain line into that pipe. The housing has one entry point on the right and two exit points (1 clean RO water & 1 waste water) on the left. The waste water comes out at that location from the housing.

Radicaljbr · 12/15/2007, 03:48 PM

Quote:

Originally posted by chris4869
I think you are misinterpreting the picture. The break, as you are referring to, is actually the exit waste water pipeline FROM the membrane housing. You connect the drain line into that pipe. The housing has one entry point on the right and two exit points (1 clean RO water & 1 waste water) on the left. The waste water comes out at that location from the housing.

Thank You!!

You are correct, I was reading the diagram wrong. If you look to quickly at the picture, one could think that the break is in the line. I was not really looking at it being and entry and exit point for the membrane.

Thansk

12/14/2007, 03:20 PM	#1
Radicaljbr Registered Member Join Date: Sep 2003 Location: Hudson, Ohio Posts: 1,293	RO/DI question about reverse flow I have a RO/DI unit. There are two outlets. One for RO only and one for RO/DI. I have my RO hooked up to my ice maker and a faucet for drinking. There is also a bladder storage tank for holding water on this line. My RO/DI is of course hooked up to my tank. I have noticed that when I am filling buckets or tanks up with my RO/DI line, it bleeds my RO tank. So I guess I am actully filling my tank up with RO water. Am I doing something wrong? Why would it reverse my flow and take RO water and go into the RO/DI line? Should it be doing this?

12/15/2007, 12:23 AM	#17
jdieck Registered Member Join Date: Dec 2002 Location: Maumee, OH Posts: 15,673	__________________ Did I write what I wrote? What the heck am I talking about! Well..... Nevermind. Current Tank Info: 225 gal reef, DSB, 40 g sump w/ LRT100 return, 37 g pre-sump, 3 MH 250 W 15K, 4 96 W PC dual actinic,ETS 1500 Skim.w/LRT70, 20 lb Ca R., 40 W UV, 1/3 HP chiller, two 350 W Htrs, Neptune II Cont., 330 P LR/ 330 P LS. 55 gal Refugium

12/15/2007, 11:54 AM	#21
chris4869 Registered Member Join Date: Jan 2006 Location: Bay Area, CA Posts: 1,006	I think you are misinterpreting the picture. The break, as you are referring to, is actually the exit waste water pipeline FROM the membrane housing. You connect the drain line into that pipe. The housing has one entry point on the right and two exit points (1 clean RO water & 1 waste water) on the left. The waste water comes out at that location from the housing. Last edited by chris4869; 12/15/2007 at 12:08 PM.

12/14/2007, 03:35 PM	#2
TammyLiz Registered Member Join Date: May 2007 Location: Fredericksburg, Va Posts: 903	I don't know anything about your model but deionization is a final step added onto reverse osmosis filtration in order to further remove impurities that remained in the RO water, so it would make sense that it would be using the RO water

12/14/2007, 05:22 PM	#5
Radicaljbr Registered Member Join Date: Sep 2003 Location: Hudson, Ohio Posts: 1,293	Perfect, now where can I find one?

12/14/2007, 05:23 PM	#6
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	It depends on how long you want to wait to make DI water. I use my pressure tank to pressurize the DI so I can make water faster, I don't have time to wait all day to make 20 gallons of DI. My time is worth more than that. I would not worry about it, with a small pressure tank you can just about fill a 5G bucket of jug in one shot without waiting. I went an extra step and at one time had two 5G pressure tanks but that still wasn't enough so I now have a14G pressure tank and can fill three 5G jugs in a very short time.

12/14/2007, 05:24 PM	#7
Radicaljbr Registered Member Join Date: Sep 2003 Location: Hudson, Ohio Posts: 1,293	I see you put one on the drain as well. Is that important? I do not think that my unit has reversed that line but you have me thinking.

12/14/2007, 05:30 PM	#9
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	The waste line(drain) has a flow restrictor not a check valve.

12/14/2007, 09:43 PM	#13
TammyLiz Registered Member Join Date: May 2007 Location: Fredericksburg, Va Posts: 903	jdieck, I love your sig line! Cracks me up. Probably most people feel like that all the time. Or, at least I like to think so, since I do.

12/14/2007, 11:06 PM	#15
Radicaljbr Registered Member Join Date: Sep 2003 Location: Hudson, Ohio Posts: 1,293	Sounds like something House would say.

12/15/2007, 10:49 AM	#18
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	Show me a check valve on the drain line??? It says "flow restrictor" and "to drain", thats it. Where you see a check valve is the other line from the RO membrane which is on a different flow path or circuit. Note that membrane housings have 2 entrances/exits on one end and 1 on the other. On the end with two fittings the one towards the outside edge is the waste line and the one towards the center is the product or good line out.

12/15/2007, 11:19 AM	#19
Radicaljbr Registered Member Join Date: Sep 2003 Location: Hudson, Ohio Posts: 1,293	I am looking at the right picture and there is only one line that says drain. Right next to that is the flow restrictor. If you keep following this line to the left the very next thing it says check valve and there is a break in the line. I do not think I am readling this wrong. Anyone else have a comment? Or is it just me reading this thing wrong?

12/15/2007, 11:39 AM	#20
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	To drain means just that. You plumb that drain line to the sink drain. It does not connect to anything else.