RODI Unit Questions

[DDon]

If everything worked fine until ro membrane and filters were changed, then you need to focus there. At this point, I would say the most likely cause is the ro membrane not being seated allowing water to bypass the membrane.

Has the amount of water being produced changed at all? If water is bypassing the membrane I would expect the amount of product water to increase.

 

[sleepydoc]

Ok - here's what I understand so far:

Current Readings:

• Tap water 29 ppm (that's very clean tap water by the way, are you sure you're measuring correctly?)
• Water after sediment/carbon filters: ??? ppm
• Water after RO membrane: 27 ppm

Your system was working fine (as far as you know) a few months ago and you changed all the filters - sediment, carbon blocks, RO membrane and DI resin.
After that you noticed that you were burning through DI resin but (as far as I can tell) you don't know if it was ever working properly after changing everything.

If your readings above are correct, It would appear that your sediment and carbon filters are not working. As I mentioned, feeding unfiltered water straight to a RO/DI membrane can ruin it pretty quickly. Start with the pre-filters and check to see that they are installed properly, gaskets in place, etc. Then check the RO/Di membrane. I just installed a new membrane from BRS and it works beautifully. BRS sells membranes made by Dow and GE, so I don't think was the membrane initially, although at this point you may need to replace it as well.

Do you have a pressure gauge on your system? What is the pressure reading? It might be worth checking the pressure before and after the sediment and carbon filters. you should se a bit of a drop with the system running. If there's no appreciable drop that would tell me there's a leak somewhere in the system.

 

[Browndawg80]

Tap water 29 ppm (that's very clean tap water by the way, are you sure you're measuring correctly?)

^This doesn't seem right to me, that number seems too low for source water.


Im starting to suspect that its never been hooked up correctly. You have no way of knowing for certain that it was ever working correctly in the first place. That is why you NEED to know the number after the membrane. If you are dead set on knowing the IN number from the tap you could always add a second TDS meter that measures the in from the tap and the out from after the sed and carbon but before the membrane. IMO that would kind of be a waste as both numbers would be the same because the sed and carbon dont really reduce TDS, rather they just protect the membrane.

A brand new DI could have easily been masking a problem elsewhere and by your own admission you're burning through DI's rapidly which is a sign that something is wrong.

However, if you believe that it was working fine before you replaced everything and now it's not I would agree with the others that something happened when you changed everything out. The changing of sediment and carbon is pretty easy so it seems more likely to me a problem with the seating of the membrane itself so I would start there. Also are you sure that you have the correct size flow restrict for the new membrane you ordered?

 

[Browndawg80]

At this point If everything appears to be installed correctly I would get a new DI cartridge installed and then move the TDS meter over as described above to get a reading after the membrane. If after doing this you get a high number after the membrane but before the DI I would also replace the membrane to rule out the possibility of it having been ruined before. The only way to solve the problem will be by verifying that the unit is working as it should stage by stage.

 

[maynardjames]

Seems if everyone is telling you what you are doing wrong! But not what might be wrong overall. Please let us know what you figure out.

 

[Mock]

Your system was working fine (as far as you know) a few months ago and you changed all the filters - sediment, carbon blocks, RO membrane and DI resin.
After that you noticed that you were burning through DI resin but (as far as I can tell) you don't know if it was ever working properly after changing everything.

If your readings above are correct, It would appear that your sediment and carbon filters are not working.

Do you have a pressure gauge on your system? What is the pressure reading? It might be worth checking the pressure before and after the sediment and carbon filters. you should se a bit of a drop with the system running. If there's no appreciable drop that would tell me there's a leak somewhere in the system.

The system was working fine AFTER the installation of everything.... I was reading 000 after I replaced everything....

The clear housings show that the sediment filters are not dirty, I have seen them dirty, they are still in good shape, they all have the gaskets on top and the refillable carbon block seats nicely.

I do not have a pressure gauge. Yet this thing is fed from the line that is used outside and it has enough pressure to soak a kid at 25 yards.

Something happened, AFTER it was all installed and working correctly. Thats the whole point and the point people are missing here. It worked, it worked great, it was pulling down water to 000 after the change of everything.

Now it isnt....

I was hoping that someone could help pinpoint any reason why a totally cleaned ( talking taken apart cleaned everything replaced, everything put back together, new automatic shut off, new RO, new filters the works) unit that was reading 000 after installation has began to read 025 within a couple months.

The only thing I have left to do is disassemble it, which I hate to do or for some reason I might be missing something. So far I havent heard what I am missing, so I guess my only option is to take it back apart and see if possibly the RO membrane has backed out, and change everything (again in as little as 3 months) and see what happens then.

Yes, we have pretty clean water, its why I havent gone crazy about tearing this thing apart but it looks as if I am going to have to. I have never had a problem with this unit in over 4 years and it was working perfectly until the tell tell sign of the DI resin was mush and I clicked the button.... Something happend to it, went from working fine to not working basically at all.

 

[Mock]

This is a photo of it that I had in photobucket.

You can see the canisters and the dual TDS meter.

It is probably no help otherwise but oh well.

 

[DDon]

Just a couple questions for clarification.
In you first post you said you were eating through DI resin like crazy but didn't worry about it since you were still getting zero tds out. Did you start going through DI resin more quickly right after the membrane swap or was it some time after?
have you noticed any other changes such as product water flow increasing or decreasing? Reject water flow change?

 

[Mock]

Just a couple questions for clarification.
In you first post you said you were eating through DI resin like crazy but didn't worry about it since you were still getting zero tds out. Did you start going through DI resin more quickly right after the membrane swap or was it some time after?
have you noticed any other changes such as product water flow increasing or decreasing? Reject water flow change?

Clarification....

After the filter, RO, everything swap.... I was reading 0 TDS.....

I dont check it on a regular basis, I just figured meh.... its reading 0 every time I look at it.

It was some time later that it we through the DI resin, I chalked it up, changed it out and it ate through that too, thats when I actually checked the TDS and found 025 on the out line....

I then flipped it to see 029 on the in line. Something went wrong with it while it was just hanging on the wall. I made up probably 100 gallons of water change water with it and it tops the tank off each day at probably around 2 gallons a day.

I have had it for four years and it has always read 0, when it started reading 005 on a regular basis even after a complete filter change minus the RO membrane, I replaced the membrane. Figured 4 years was enough and I wasnt getting 0 anymore.

It worked fine for a while, it read 0 for weeks and then it just quit.

As if RO membrane is flawed or loosened itself and started leaking around it.

There is no change in water usage.

 

[Mock]

I took the back flush off of it when I redid all the lines, I might put it back on and run it backwards to see if there is sediment trapped and not letting water through the RO membrane.....

Thats the only thing I can think of.

 

[Shaummy]

Here is my guess. When you replaced everything, the RO membrane was hardly doing it's job and passing approximately 25 TDS (close to your source water) through to your DI cartridge.

The DI cartridge also being new...produced your 0 TDS output water and gave you the illusion that it was all working properly because it could handle the 25 TDS that it was being fed, but it will exhaust itself much more quickly.

Once the DI was toast, you saw your high TDS in the output water.

The first place to look is at the RO membrane, since as you mentioned it's pretty straightforward to install the sediment and carbon filters.

It's possible that the membrane didn't get seated properly in the housing, it was put in backwards, it was a GPD that didn't match your flow restrictor, or you have the restrictor in the wrong place/tube.

The other thing that comes to mind is that the new carbon filters were not rinsed before connecting them to the RO membrane and it has clogged it. I usually don't do this either, so I doubt it's your issue.

It could be any of those so it's hard for us to pinpoint an exact cause of your problem, but the RO is where I would start to look.

 

[Browndawg80]

Mock, it's not possible for an RO unit to be hanging on the wall working fine and then the next minute be broken. The way I see it there are only 2 possibilities...

1. You accidentally installed the most recent membrane incorrectly or got one or more of the lines crossed if you even took them off.

2. The unit has never been working right since you've had it.

That's it. It's either one or the other. We all know that you believe it's been working right in the past. If that's truly the case it should be a simple matter of double checking that all components including the membrane are seated and installed correctly. If they are then the unit has never worked right. Here are some facts that that support this theory.

1. You are and as far as I can tell have been burning through DI resin for some time. This is not in any way normal and is a huge red flag.
2. You have twice now mentioned that you don't pay that much attention to the unit including normal changing of the sediment and carbon which prevents damage to the membrane.
3. You said early on that you thought you remembered your in source number being in the hundreds. Now you say it's reading an extremely low number like 027. Although this is possible something still seems fishy. Again myself and others have questioned this.

At this point it seems like the biggest obstacle in the way of getting this thing fixed is you. My best guess is that you have a crossed line on the unit somewhere. You may very well be correct that this is a new problem related to your most recent changing and cleaning but my question to you is HOW DO YOU KNOW??? If your answer is " because i had an out reading of zero." then that's not good enough! As myself and others have told you a DI cartridge by itself with no help at all from the membrane can produce a 000. However if you aren't willing to at least use the TDS meter to do its job and check that that each stage is working as its supposed to be then take the unit to somebody who will. There is no quick easy answer to this, simply put you are going to have to troubleshoot this thing stage by stage with the TDS meter or take it to somebody who will. Not trying to be a jerk and I apologize if I've offended you but I'd hate to hear about your system crashing because it sounds pretty sweet based off of your sig. If this thing doesn't get resolved it's only going to be a matter of time before your system starts showing signs of distress if you're using that water now. Good luck.

 

[Browndawg80]

Here is my guess. When you replaced everything, the RO membrane was hardly doing it's job and passing approximately 25 TDS (close to your source water) through to your DI cartridge.

^ exactly. Because there's always been a problem OR You neglected the sediment and carbon for too long and damaged the membrane.

The DI cartridge also being new...produced your 0 TDS output water and gave you the illusion that it was all working properly because it could handle the 25 TDS that it was being fed, but it will exhaust itself much more quickly.

Once the DI was toast, you saw your high TDS in the output water.

^ YES.

The first place to look is at the RO membrane, since as you mentioned it's pretty straightforward to install the sediment and carbon filters.

It's possible that the membrane didn't get seated properly in the housing, it was put in backwards, it was a GPD that didn't match your flow restrictor, or you have the restrictor in the wrong place/tube.

The other thing that comes to mind is that the new carbon filters were not rinsed before connecting them to the RO membrane and it has clogged it.

It could be any of those so it's hard for us to pinpoint an exact cause of your problem, but the RO is where I would start to look.

^ At the end of the day the only way to fix this is to use the TDS meter to verify that each stage is working as it should. The problem you have now is that you don't know with 100% clarity that the membrane you have isn't already shot. Being only 3 months old it might be ok but you may want to bite the bullet and start fresh again. You definitely need a new DI.

 

[Shaummy]

^ At the end of the day the only way to fix this is to use the TDS meter to verify that each stage is working as it should. The problem you have now is that you don't know with 100% clarity that the membrane you have isn't already shot. Being only 3 months old it might be ok but you may want to bite the bullet and start fresh again. You definitely need a new DI.

Agreed....check the membrane is seated and is installed properly, and that you have all the tubes going where they should. Then....fire it up and use your TDS meter to measure after the RO stage instead of the total output.

Then you'll have source water, and post RO TDS readings and you can see if the RO is working properly. Keep in mind that the TDS will be high for a few minutes so run it for a bit before testing it.

We'll get this going for you the best we can Mock...just got to meet us half way and do some diagnosis.:thumbsup:

 

[Opus123]

Just to throw some usage figures into this, if your water is 25 tds after the membrane, then your DI would last for about 180 gallons. If your membrane was working correctly and 29 tds is correct for your tap water, then you should get over 3000 gallons of water before the DI is depleted. This is assuming your membrane is running at 95% efficiency.

 

[Shaummy]

Hey Mock...were you able to get this going again? Hope it was something simple.

I can try to take a couple of pics of the connections on my RODI if you think it will help.

 

[padi200]

I would start with just taking it all apart, looking at each part including the seals on the ends of everything and put it back together. Then if it doesn't work, I would be systematic about the process. Check TDS at each step with an INLINE TDS meter. It is easy to move it to each step and see where it is not working. I bet you are going to find the answer that way.
One thing that can ruin a new membrane is hot water by accident. Any chance that happened?