fishkeeprian
Active member
The ppm before DI is 21ppm and water out through Di is 3ppm and water flow in is 227ppm. Does thus sound right?
New ro unit help
- Thread starter fishkeeprian
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The ppm before DI is 21ppm and water out through Di is 3ppm and water flow in is 227ppm. Does thus sound right?
No your kinda right, I did not remember some canisters do in fact have both in/out at the top....I have not had one of these for years, mine all have input at one end output at other. If I put water in the top, sometimes the water can "channel" itself through the Resin, and not get as much contact and leads to slight TDS readings 1-6 at tines. When I reverse the flow, the water cannot "channel" and readings are 0-1.
Sorry that's my fault in assuming all RODI units process the same way, thus is incorrect
So now I know how they both work, but seems that they can still be reversed....
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IMO, 21 before DI is about right but should do better, I still think DI should still be 0-1.
Mine is 146, 11, and the output reads between 0-2, but many factors can affect end result.
My apologies if I mixed you up in the direction, the RODI's I work with do not have input/output at the top, mine have input on one end, out on the other, so your process is different than mine, thus, the direction does not apply to your filter.
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fishkeeprian
Active member
The is a separate cartridge you fill with the di and then put into the canister. The water can only be pushed through the bottom and out the top.
lpsouth1978
New member
This seems like a pretty low rejection rate. With 227 in and 21 out you are getting about 90.2% rejection. Most membranes get 96-98% rejection. There could be a couple of things causing this. Water temp could be so cold that it reduces rejection or pressure is to low. Do you know the temp going into the unit and the pressure? I assume the pressure is ok, since it has a booster pump.
If neither of these are the issue, more investigation will be needed.
lpsouth1978
New member
Your pressure is fine, but the temp is a bit lower than ideal. There really isn't anything you can do about that. Besides that really shouldn't affect the final product. It will just cause your resin to exhaust faster.
My last thought is that it could be that the resin is getting old. I know the unit is new to you, but if the manufacturer filled the canisters in advance and then the unit sat in their warehouse a while, it could already be somewhat depleted. The resin starts to deplete as soon as it is exposed to air. This is a bit of a long shot, but could be an part of the problem.
I'm sorry I couldn't help you solve this, but I am out of ideas. Maybe someone else will chime in some other thoughts.
fishkeeprian
Active member
No sure what the pressure is but yes it has a booster pump fitted and it comes out at a reasonable speed compared to some I've seen.
The Di was in a sealed bag and I had to fill the canister myself. I checked on line and the ro membrane should givery a 97% rejection rate.
It's summer here and most days for about 2 months it's been 20 plus c.
I've been running the unit again tonight and it dropped to 2ppm.
fishkeeprian
Active member
Just an update if anyone is interested.
I have spoken with the manufacturer and they are sending me out new di resin and ro membrane as they agreed my rejection rate is low.
I have spoken with the manufacturer and they are sending me out new di resin and ro membrane as they agreed my rejection rate is low.
der_wille_zur_macht
Team RC
Can you measure the product to waste ratio? Do you know you have the right flow restrictor and it's installed correctly? Do you have any "complications" in your drain or product lines? (ie are they really long, kinked, connected to something that may introduce a restriction, etc.)?
fishkeeprian
Active member
There is a metre or so of extra flow in line that I have wound up. And a metre or so of extra line wound up on the waste line. I've put the small ball valve just before the t connection for the tds probe of the water going in line.
fishkeeprian
Active member
If I use the little ball valve to restrict the flow in it mess with the pump cutting it in and out.
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