RO/DI Water Unit pressure question

[hipertec]

I have an old 5 stage with DI unit from Coralife. Its about 8 years old and filters will be replaced.
I made an adapter to hook up to the gardening hose line. But how do I manage the pressure? Is there a gauge i can adapt to the intake and put a valve to control the garden hose pressure?
Also for the exit of the bad water, how do I know how much water should be wasted? There is only a turn valve that controls the flow of the bad water.

 

[Opus123]

You probably don't need to worry about the pressure from the water faucet. I've never heard of anyone having too much pressure. You can always buy a gauge that hooks up to the RO unit that tells you the current water pressure. As for the waste water, 3 to 1 seems to be the norm. Check the RO membrane you end up buying and see if it says what it should produce.

 

[mcgyvr]

Open the hose all the way..
and typically its 4:1 waste:good..

have fun

 

[hipertec]

Thanks Guys- So I will open the water faucet all the way.
Is there a easier or better way to gauge the waste water of 3(waste)-1(good) or 4-1? There is a waste water dial that is attached to my waste water exit hose that controls how much water will exit out of there.

 

[LQT]

Optimally it should be a 4:1 ratio. That should be determined by water pressure and temperature, not a dial. When you say dial to regulate waste water, do you mean a membrane flush valve on the waste water line or on the flow restrictor? For clarification, do you have a photo?

 

[hipertec]

Optimally it should be a 4:1 ratio. That should be determined by water pressure and temperature, not a dial. When you say dial to regulate waste water, do you mean a membrane flush valve on the waste water line or on the flow restrictor? For clarification, do you have a photo?

Its actually a valve that controls the waste water flow line from exiting out.

There is also a flow restrictor inside the hose fitting coming from the last DI housing that attaches to the waste water line.

Ill take a picture when I get home.

 

[LQT]

Please do so. The flow restrictor should be on the line exiting the RO membrane housing on the waste side, not the line exiting the DI canister.

 

[LQT]

double post

 

[mcgyvr]

Its actually a valve that controls the waste water flow line from exiting out.

There is also a flow restrictor inside the hose fitting coming from the last DI housing that attaches to the waste water line.

Ill take a picture when I get home.

No.. Thats more than likely just a flush valve.. Its meant to be closed during normal operation nd only used to "flush" the membrane periodically.. its not meant to regulate waste ratio..
(edit.. oops just saw you said out of the DI stage.. If so its still a "flush" valve to allow you to "flush" off the high initial TDS that is present when you first start up the system)

To see the waster ratio simply put the "good" outlet and "waste" into their own buckets... Run if for "X" amount of time and measure the volume of water between each bucket..

If the waste one has 4 gallons and the good has 1 gallon.. Then its 4:1..

 

[Buckeye Hydro]

We always recommend two tools and mandatory if you are going to have an RODI system:
Pressure gauge, and
TDS meter.

You'll want a pressure gauge add on kit. Inexpensive and easy to install. Your issue with pressure, if you have one, will be LOW pressure, not pressure that is too high. Install the gauge so that it reads the pressure right before the membrane (after all the prefilters).

To check your waste water to purified water ratio - line up 8 identical cups (we use Solo beer cups) in front of the system. With your waste water tube in one hand and the purified water tube in the other hand, how many cups do you fill with waste water in the time it takes you to fill one cup with purified water? Use a flow restrictor that gives you something between 3:1 and 5:1.

I recommend against using an adjustable flow restrictor on the little residential-scale RODI systems used in this hobby. Can go into more detail if you'd like.

Russ