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RODI not building any pressure


Tyler Livingston
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I turned on my RODI today (BRS 5 stage), and I get no pressure registering on the gauge, no good water coming to the DI stage.  Water supply seems good although I don't have an independent gauge to check source pressure (it seems normal though). I tried taking the sediment and carbon block filters out of the first three stages - still get no pressure building on the gauge. Any ideas?

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I replaced the sediment and carbon filters last month - made 50 gallons of water for a couple water changes earlier this month. Didn't use it for a week or two, then nothing when I turned it on yesterday. 

Also I double checked the flush valve.  When the valve is closed (water going through the RO membrane), I get a little bit of waste water and no good water. If I flip the back flush valve, waste water volume goes up quitter a bit.

I've never changed the RO membrane - could that be the issue?

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Ether your source has adjusted the pressure, for God's knows what reason (new taps into main, pump adjustment at treatment plant, etc...) or your membrane is shot but that wouldnt really do anything to your pressure it would just let in more bad water. you should really have a booster pump if you don't.

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Source pressure seems normal.  I'm guessing the RO is shot after 2+ years and a recent change of upstream carbon filters without sufficient flushing.  New RO membrane is on the way from Amazon.  I typically get 50 psi to the unit.  I thought about a booster but I guess haven't found it necessary yet.

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It would be more efficient at a higher pressure.  Something I learned in my research is how important it is to flush that membrane after each use to make it last longer.  I am going to use my apex and a valve to do that automatically for me each time I fill my RODI tank.  

That being said I'm thinking a plugged membrane would still show pressure but have no output.  After 2 years it's probably a good idea to change it, hope it solves your problem.

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2 hours ago, Muttley000 said:

It would be more efficient at a higher pressure.  Something I learned in my research is how important it is to flush that membrane after each use to make it last longer.  I am going to use my apex and a valve to do that automatically for me each time I fill my RODI tank.  

That being said I'm thinking a plugged membrane would still show pressure but have no output.  After 2 years it's probably a good idea to change it, hope it solves your problem.

I may still think about a pump.  Your second point is my more immediate concern - I guess I'll find out Wednesday when I get the new RO membrane.

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easiest way I can explain the need for a pump is.... no pump membrane runs at 95% rejection rate, sounds good but if you get a pump a set it around 85-90 psi the membrane will run at 98-99%, it dosent sound like much but for each % point above what you currently have you double the di resin canister. Di resin runs what 45 bucks and lasts 6-12 months depending on the amount of ro water you make. Do the math and the 150 dollar booster pump is a no brainer, I resisted for a couple years but really its wasting money without the pump   get a aquatec 8800 pump and just buy a auto flush kit (flushes the membrane every couple hours and before and after every time you make a new can of rodi water) both I would get from BRS http://www.bulkreefsupply.com/1-4-aquatec-8800-booster-pump-kit.html?gclid=CO_x6p_77NECFUKewAodM2gIVQ and http://www.bulkreefsupply.com/aquatec-auto-flush-flow-restrictor.html

Edited by redevil13
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RODI is working again but I'm not exactly sure if the issue was a blocked RO membrane or a blockage in one of the fittings.  I installed the new RO membrane and still wasn't getting any pressure on the gauge.  At that point I started taking some of the tubing apart to test sections individually, verify source water pressure, and blow through fittings to make sure they were open.  I didn't find anything obvious, but when I hooked everything back up I had full pressure (about 55 psi).  Ran the unit for about an hour, then started making good water (verified with the built-in TDS meter).

Long story short, I probably had some kind of blockage in the little elbow at the outlet of the sediment/carbon filter stages.  The new RO membrane was probably about due for replacement anyway.

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On 1/31/2017 at 1:01 PM, redevil13 said:

easiest way I can explain the need for a pump is.... no pump membrane runs at 95% rejection rate, sounds good but if you get a pump a set it around 85-90 psi the membrane will run at 98-99%, it dosent sound like much but for each % point above what you currently have you double the di resin canister. Di resin runs what 45 bucks and lasts 6-12 months depending on the amount of ro water you make. Do the math and the 150 dollar booster pump is a no brainer, I resisted for a couple years but really its wasting money without the pump   get a aquatec 8800 pump and just buy a auto flush kit (flushes the membrane every couple hours and before and after every time you make a new can of rodi water) both I would get from BRS http://www.bulkreefsupply.com/1-4-aquatec-8800-booster-pump-kit.html?gclid=CO_x6p_77NECFUKewAodM2gIVQ and http://www.bulkreefsupply.com/aquatec-auto-flush-flow-restrictor.html

 

Color-changing DI resin is $12 at bulk reef supply and I change it about once a year, so the return on investment is more than a couple years for me.  That said, I do like the idea of getting better efficiency when possible.  @Joe has a pump for sale I've been eyeing, but it's not a must have right now.

 

 

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32 minutes ago, Tyler Livingston said:

 

Color-changing DI resin is $12 at bulk reef supply and I change it about once a year, so the return on investment is more than a couple years for me.  That said, I do like the idea of getting better efficiency when possible.  @Joe has a pump for sale I've been eyeing, but it's not a must have right now.

 

 

You would love the pump as I have the same one. Having good pressure will make your filters last longer as well. 

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