Adding a fast flush to an RO/DI unit

[rk4435]

I bought a Spectrapure RO/DI yesterday that I am very happy with because it is twice as fast as the previous Air,Water & Ice unit.

I hook up to my kitchen sink weekly so the unit tends to sit for several days. The AWI folks told me about the fast flush feature on their unit an recommended that I use it to kind of cleanse the unit before collecting water again and to extend membrane life.

Sadly the Spectrapure does not have a fast flush so I was wondering what others think;

-Is a fast flush really necessary or is it ok to simply toss some ro/di when you first start collecting?

-If it is necessary does anyone have experience adding one?

The Spectrapure folks did not return my call today and I suspect they may be out for Christmas.

 

[willie1983]

http://lmgtfy.com/?q=http%3A%2F%2Fwww.nhreefclub.org%2Findex.php%3Ftopic%3D4006.0">http://lmgtfy.com/?q=http%3A%2F%2Fwww.nhreefclub.org%2Findex.php%3Ftopic%3D4006.0</a>
I was given this site by jenn and yes I was told it does help extend the life of your membrane and yes I also added it to my unit I flush before and after each use for a minute

 

[rk4435]

Thanks for the link Willie. That looks like what I need, I may be too dumb to master it but it's something I can try.

 

[willie1983]

rk4435;1003947 wrote: Thanks for the link Willie. That looks like what I need, I may be too dumb to master it but it's something I can try.

No I think it's pretty easy it was my first time as well

 

[jbdreefs]

FWIW, BRS also recommends periodic flushes to extend the life of the membrane.

 

[freezerrat]

I have a Specrapure unit with this type of setup. I'm just curious if anyone knows the mechanics of how it works? It looks to me like a split, and two parallel lines then they come back together. Both lines start at the same place and end at the same place. It seems to me that with the valve open or closed to water takes the same path. I know I have to be wrong but I don't see it.

 

[rk4435]

I'm uneasy about it because I'm not sure where to cut. I have not heard back from Spectrapure yet. I'm hoping they have some unit specific instructions. I'll update if I hear from them freezerrat.

 

[redstang]

freezerrat;1004049 wrote: I have a Specrapure unit with this type of setup. I'm just curious if anyone knows the mechanics of how it works? It looks to me like a split, and two parallel lines then they come back together. Both lines start at the same place and end at the same place. It seems to me that with the valve open or closed to water takes the same path. I know I have to be wrong but I don't see it.

What the valve does is bypass the flow restrictor allowing a significantly greater flow rate than the flow restrictor allows. This is supposed to "clean" the membrane so to speak and keep gunk from accumulating on it.

 

[redstang]

rk4435;1004050 wrote: I'm uneasy about it because I'm not sure where to cut. I have not heard back from Spectrapure yet. I'm hoping they have some unit specific instructions. I'll update if I hear from them freezerrat.

You need to find out where your flow restrictor is and create a bypass to go around it.

 

[freezerrat]

alt="" />
It's in the waste line on my unit. I got this secondhand so I don't know if its right. Like I said, I don't see how it works.

 

[redstang]

freezerrat;1004056 wrote:

alt="" />
It's in the waste line on my unit. I got this secondhand so I don't know if its right. Like I said, I don't see how it works.

Your flow restrictor is located in the solid blue tubing. It restricts the flow through the membrane. When you open the valve it significantly reduces the flow resistance as the tubing is wide open. Think of the flow reducer as a valve that's shut 95% of the way permanently. Opening the bypass valve allows the full flow rate of the tubing.

 

[freezerrat]

Thanks, that makes sense. I didn't know there was a restrictor in there. The link in a post above shows it. But it makes me think that simply putting a valve on the outlet and keeping it mostly closed would achieve the same result without extra tubing and adapters. Just restrict flow with the valve and then open it wide to flush. No?

 

[jbdreefs]

In theory, yes. Restricting the flow correctly so that the RODI works correctly is the challenge.

 

[redstang]

freezerrat;1004068 wrote: Thanks, that makes sense. I didn't know there was a restrictor in there. The link in a post above shows it. But it makes me think that simply putting a valve on the outlet and keeping it mostly closed would achieve the same result without extra tubing and adapters. Just restrict flow with the valve and then open it wide to flush. No?

Theoretically yes, practically probably not lol!

 

[grouper therapy]

freezerrat;1004068 wrote: Thanks, that makes sense. I didn't know there was a restrictor in there. The link in a post above shows it. But it makes me think that simply putting a valve on the outlet and keeping it mostly closed would achieve the same result without extra tubing and adapters. Just restrict flow with the valve and then open it wide to flush. No?

Many commercial units are set up that way. Like has been mentioned you would need to monitor the tds levels just after the Membrane to tune it properly and that would not be practical. A needle valve is typically better suited for these application. Using two valves is still advantageous.

 

[freezerrat]

Yeah, I figured it couldn't be that simple. People get paid to engineer these things for a reason.

 

[rk4435]

The original solution link made sense somewhat, but this video really helps. The best part of any of this is that the 1/4 inch tubing is cheap, if you screw up just cut a new piece and forget the flush until you have a better grasp.

I searched for this before posting the question and didn't find it. A day and three beers later BAM it's there.

https://www.youtube.com/watch?v=LfvMdoMOwpI">https://www.youtube.com/watch?v=LfvMdoMOwpI</a>


The video is from Spectrapure.

 

[redstang]

Okay, so I did this today. Easy enough though I will modify it a bit before I use it. The way it's setup it will still run the discharge through my DI unit so I'll put in another valve to stop flow to the DI and just run the flow through the bypass out to the yard.

 

[rk4435]

I forgot to update last night but I did speak with a rep from Spectrapure and he sent me info on adding a fast flush. I'll provide the link to the parts. I bet it's half or less money to buy it on your own but I ordered for convenience.

 

[rk4435]

I added the fast flush tonight with the part and instruction from Spectrapure. I'm not mechanically inclined but it was easy, three to four minutes at most.