New ro unit help

fishkeeprian · 08/14/2018, 02:31 PM

Hello I have just got a new RO unit as below and I'm getting a reading of 3ppm from my water out and not sure why I'm not getting 0 as I'm sure this unit is capable of.

I've ran the unit for a while (made about 25l of water)and flushed it but made no difference any ideas please?

https://www.vyair.com/pumped-4-stage...sin-stage.html

Thanks

lpsouth1978 · 08/14/2018, 02:46 PM

Are you storing the water at all before testing, or are you taking it straight from the output and testing? What is the TDS of your feed water (from the tap), and after the membrane (before DI)? Also, What did you calibrate your TDS meter with?

fishkeeprian · 08/14/2018, 03:14 PM

Quote:

Originally Posted by lpsouth1978

Are you storing the water at all before testing, or are you taking it straight from the output and testing? What is the TDS of your feed water (from the tap), and after the membrane (before DI)? Also, What did you calibrate your TDS meter with?

Not storing the water before testing the 3ppm reading Straight out the output. The reading I'm getting is from the inline tds metre. The water going in 234ppm, not sure how to test before the Di?
I've not calibrated the tds metre it says it's ready to use out the box.

lpsouth1978 · 08/14/2018, 03:22 PM

It is hard to say why you are getting 3ppm. Assuming 96% rejection from the Membrane, you should only be around 10ppm before DI. The DI resin should easily be able to get you down to 0ppm. My first thought would be that the TDS meter is not properly calibrated. If the meter can be calibrated, I would start there. You could also get an inexpensive hand held TDS meter, calibrate it with calibration solution (NOT RO water) and see if you get a different result. Maybe someone in your are has one and can double check the TDS for you.

fishkeeprian · 08/14/2018, 03:39 PM

Agreed. Think I will start with tds metre calibration. Which fluid do I need? Is it the 342ppm fluid to calibrate?

Also do I need to flush the unit in between each use?

lpsouth1978 · 08/14/2018, 03:45 PM

Quote:

Originally Posted by fishkeeprian

Agreed. Think I will start with tds metre calibration. Which fluid do I need? Is it the 342ppm fluid to calibrate?

Also do I need to flush the unit in between each use?

Yes, I use 342ppm calibration solution for mine. Flushing the membrane before making water won't really improve the TDS of your RO water, but it will prolong the life of your membrane, and keep it from clogging and slowing.

fishkeeprian · 08/14/2018, 03:56 PM

Quote:

Originally Posted by lpsouth1978

Yes, I use 342ppm calibration solution for mine. Flushing the membrane before making water won't really improve the TDS of your RO water, but it will prolong the life of your membrane, and keep it from clogging and slowing.

How long of a flush before I produce water?

lpsouth1978 · 08/14/2018, 04:05 PM

It doesn't need much. I just flush mine for a couple of minutes.

Uncle99 · 08/14/2018, 04:15 PM

Your pushing water up the DI cartridge right?
Down can lead to channeling and a slight increase in TDS output.

Your TDS in coming is a bit high at 234, so not a big surprise, make sure there are no cracks or small leaks, if you get a hand held, check in the RODI tank, not a glass.

fishkeeprian · 08/14/2018, 04:21 PM

Quote:

Originally Posted by lpsouth1978

It doesn't need much. I just flush mine for a couple of minutes.

I got a non return valve as part of the connecting kit but doesn't say where this should be fitted. Any ideas?

fishkeeprian · 08/14/2018, 04:22 PM

Quote:

Originally Posted by Uncle99

Your pushing water up the DI cartridge right?
Down can lead to channeling and a slight increase in TDS output.

Your TDS in coming is a bit high at 234, so not a big surprise, make sure there are no cracks or small leaks, if you get a hand held, check in the RODI tank, not a glass.

What do you mean up?

lpsouth1978 · 08/14/2018, 05:19 PM

Quote:

Originally Posted by fishkeeprian

What do you mean up?

He is talking about the DI canister. Try Positioning your DI canister vertically, so the water goes from the bottom to the top. This eliminates the channeling of water so you don't have and get through without coming in contact with the resin.

I don't know where is best to install the check valve, as I haven't ever used one on an RO system.

fishkeeprian · 08/14/2018, 05:24 PM

Quote:

Originally Posted by lpsouth1978

He is talking about the DI canister. Try Positioning your DI canister vertically, so the water goes from the bottom to the top. This eliminates the channeling of water so you don't have and get through without coming in contact with the resin.

I don't know where is best to install the check valve, as I haven't ever used one on an RO system.

The DI canister is already vertical.

outssider · 08/14/2018, 05:24 PM

Quote:

Originally Posted by fishkeeprian

What do you mean up?

the water should be going from the ro unit to the bottom of the resin chamber and going up and then out...

fishkeeprian · 08/14/2018, 05:26 PM

Quote:

Originally Posted by lpsouth1978

He is talking about the DI canister. Try Positioning your DI canister vertically, so the water goes from the bottom to the top. This eliminates the channeling of water so you don't have and get through without coming in contact with the resin.

I don't know where is best to install the check valve, as I haven't ever used one on an RO system.

The unit has a built in flush valve and it says installing it inline with the waste pipe.

Do I flush before and after producing water?

Uncle99 · 08/14/2018, 08:18 PM

Quote:

Originally Posted by fishkeeprian

What do you mean up?

Water can flow either top to bottom and then to holding tank, or bottom to top.
I have seen both hookups, but when the water comes from RO and is pushed from the bottom of the DI cartridge, it ensures an even contact with the resin at all times.

fishkeeprian · 08/14/2018, 11:57 PM

How do I know if it is being push from bottom or top?

I also have a couple of ball valves so if I put one on the out to slow the water down coming out so it has more contact time with the Di will this help?

Uncle99 · 08/15/2018, 06:33 AM

Quote:

Originally Posted by fishkeeprian

How do I know if it is being push from bottom or top?

I also have a couple of ball valves so if I put one on the out to slow the water down coming out so it has more contact time with the Di will this help?

I use my RODI unit without modifications, changing things (as I found out) sometimes leads to more TDS and proves I know little of water purification techniques.

There must be a water line coming out of your RO membrane canister right?
This line would take the RO water and deliver it to the DI canister. It is beneficial that this line enters the DI canister (which should be standing length wise vertically) at the bottom. At the top, you should have another line which goes to your RODI holding tank.

If the RO water enters the DI canister at the bottom, the water had no choice but to move upward through the resin, out the top, and into the holding bucket.

homer1475 · 08/15/2018, 08:05 AM

Quote:

Originally Posted by Uncle99

If the RO water enters the DI canister at the bottom, the water had no choice but to move upward through the resin, out the top, and into the holding bucket.

You do realize that all canisters have the input/output lines at the top of the canister? It's the inner cartridge and whether the input line is at the top of the cartridge or on the side determines where the water goes?

If the incoming water is on the outside of the inner cartridge, it's being pushed up through the resin. If the incoming water is at the top of the cartridge, the the water is being forced down through the resin.

I'm pretty sure you do realize how they work, it's just your explaining makes it sound like the water line should be at the bottom of the canister.

fishkeeprian · 08/15/2018, 08:48 AM

When I first saw the DI Resin canister fill it was filling up the water around the side of the cartridge so I assume it's being pushed up through the Resin?

Thanks

fishkeeprian · 08/15/2018, 11:44 AM

Quote:

Originally Posted by lpsouth1978

Are you storing the water at all before testing, or are you taking it straight from the output and testing? What is the TDS of your feed water (from the tap), and after the membrane (before DI)? Also, What did you calibrate your TDS meter with?

The ppm before DI is 21ppm and water out through Di is 3ppm and water flow in is 227ppm. Does thus sound right?

Uncle99 · 08/15/2018, 11:59 AM

Quote:

Originally Posted by homer1475

You do realize that all canisters have the input/output lines at the top of the canister? It's the inner cartridge and whether the input line is at the top of the cartridge or on the side determines where the water goes?

If the incoming water is on the outside of the inner cartridge, it's being pushed up through the resin. If the incoming water is at the top of the cartridge, the the water is being forced down through the resin.

I'm pretty sure you do realize how they work, it's just your explaining makes it sound like the water line should be at the bottom of the canister.

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....

Uncle99 · 08/15/2018, 12:06 PM

Quote:

Originally Posted by fishkeeprian

The ppm before DI is 21ppm and water out through Di is 3ppm and water flow in is 227ppm. Does thus sound right?

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.

fishkeeprian · 08/15/2018, 12:07 PM

Quote:

Originally Posted by Uncle99

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

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 · 08/15/2018, 12:07 PM

Quote:

Originally Posted by fishkeeprian

The ppm before DI is 21ppm and water out through Di is 3ppm and water flow in is 227ppm. Does thus sound right?

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.

08/14/2018, 02:31 PM	#1
fishkeeprian Registered Member Join Date: Feb 2016 Location: England, Earl Shilton Posts: 1,452	New ro unit help Hello I have just got a new RO unit as below and I'm getting a reading of 3ppm from my water out and not sure why I'm not getting 0 as I'm sure this unit is capable of. I've ran the unit for a while (made about 25l of water)and flushed it but made no difference any ideas please? https://www.vyair.com/pumped-4-stage...sin-stage.html Thanks __________________ If in doubt ask!

08/14/2018, 02:46 PM	#2
lpsouth1978 Registered Member Join Date: Jan 2007 Location: Arizona Posts: 915	Are you storing the water at all before testing, or are you taking it straight from the output and testing? What is the TDS of your feed water (from the tap), and after the membrane (before DI)? Also, What did you calibrate your TDS meter with? __________________ Current tank: 40B work in progress w/20L sump

08/14/2018, 03:22 PM	#4
lpsouth1978 Registered Member Join Date: Jan 2007 Location: Arizona Posts: 915	It is hard to say why you are getting 3ppm. Assuming 96% rejection from the Membrane, you should only be around 10ppm before DI. The DI resin should easily be able to get you down to 0ppm. My first thought would be that the TDS meter is not properly calibrated. If the meter can be calibrated, I would start there. You could also get an inexpensive hand held TDS meter, calibrate it with calibration solution (NOT RO water) and see if you get a different result. Maybe someone in your are has one and can double check the TDS for you. __________________ Current tank: 40B work in progress w/20L sump

08/14/2018, 03:39 PM	#5
fishkeeprian Registered Member Join Date: Feb 2016 Location: England, Earl Shilton Posts: 1,452	Agreed. Think I will start with tds metre calibration. Which fluid do I need? Is it the 342ppm fluid to calibrate? Also do I need to flush the unit in between each use? __________________ If in doubt ask!

08/14/2018, 04:05 PM	#8
lpsouth1978 Registered Member Join Date: Jan 2007 Location: Arizona Posts: 915	It doesn't need much. I just flush mine for a couple of minutes. __________________ Current tank: 40B work in progress w/20L sump

08/14/2018, 04:15 PM	#9
Uncle99 Crab Free Zone Join Date: Sep 2017 Location: Ontario, Canada Posts: 2,906	Your pushing water up the DI cartridge right? Down can lead to channeling and a slight increase in TDS output. Your TDS in coming is a bit high at 234, so not a big surprise, make sure there are no cracks or small leaks, if you get a hand held, check in the RODI tank, not a glass.

08/14/2018, 11:57 PM	#17
fishkeeprian Registered Member Join Date: Feb 2016 Location: England, Earl Shilton Posts: 1,452	How do I know if it is being push from bottom or top? I also have a couple of ball valves so if I put one on the out to slow the water down coming out so it has more contact time with the Di will this help? __________________ If in doubt ask!

08/15/2018, 08:48 AM	#20
fishkeeprian Registered Member Join Date: Feb 2016 Location: England, Earl Shilton Posts: 1,452	When I first saw the DI Resin canister fill it was filling up the water around the side of the cartridge so I assume it's being pushed up through the Resin? Thanks __________________ If in doubt ask!