RO/DI filter help

superfirefly · 10/12/2010, 05:38 PM

I have an old water general system that has been running great for almost 5 years. At the begging of the summer my out put slowed to barely a drip a second. At that point I replaced all filter and RO membrane. It was better for a month or so now it is back to a drip every few seconds. I just got a pressure gauge and I am trying to figure out what the numbers mean.

If I disconnect the input line from the unit and dead end it into a pressure gauge I get between 70 and 80 PSI. I then dead ended it on the output of my 3 filters. I got 70 PSI. Next I put it inline between the 3 filters and the RO/DI, I get 12. It doesn't matter if I have the unit wide open or turned off. That number doesn't change.

Does that mean I have problems with my membrane?

Thanks for any help.

JEFFRO33 · 10/12/2010, 06:00 PM

Ro/di will only produce water drop by drop.You may want to check the pressure in the storage tank.Make sure there is no water in the tank when checking.You should have a reading of 7psi on a empty storage tank.If not repressurize it.Hope this helps!

superfirefly · 10/12/2010, 06:18 PM

I have the storage tank turned off for my testing. I know what you mean by drip by drip but I am not even getting that. I left it on for 18 hours and only 1/4 filled a 20G brute trash can.

After totally disassembling the unit and doing some more research I am thinking it is the flow restrictor. Does that make sense?

Tat2demon · 10/12/2010, 06:34 PM

Quote:

Originally Posted by JEFFRO33

Ro/di will only produce water drop by drop.You may want to check the pressure in the storage tank.Make sure there is no water in the tank when checking.You should have a reading of 7psi on a empty storage tank.If not repressurize it.Hope this helps!

Ive had 2 ro/di units and they both produce a nice steady stream. If youre just getting drop by drop you probably have a problem with your unit.

superfirefly · 10/12/2010, 06:42 PM

After reseating the ro membrane I am now getting 25 PSI and a steady drip. Does that sound right or should the pressure be higher?

JEFFRO33 · 10/12/2010, 07:52 PM

A steady drip sounds about right.Check with a tds meter and compare to the untreated water.

superfirefly · 10/12/2010, 09:13 PM

Well my steady drip is now gone and the system is reading 12 PSI again. I think I will try a new flow restrictor since the one I have is known to have problems.

jjstecchino · 10/12/2010, 10:00 PM

You may have a problem with clogged prefilters. Keep in mind that what matters is the pressure of the flowing water, not the static pressure of the water not running. Let me explain with an example: If the prefilters are clogged and let only a trickle of water through, this will cause a significant pressure drop just before the membrane and the membrane will produce very little water. On the other hand if the water production is shut off, slowly the pressure after the prefilters will rise to the nominal pressure of the household water supply. From what you describe my bet would be that the prefilters are clogged. If you have a standard setup with a 5 micron filter followed by a 5 micron carbon block, followed by the 1 micron carbon block, usually this last filter is the one that clogs the most. You can test the system by removing the 1 micron carbon block from the canister and if water production goesup topar,replace the filter. It does not sound you have a problem with the restrictor.

superfirefly · 10/14/2010, 10:00 AM

Thanks for the top jjstecchino, you were correct. As soon as I removed that last filter the pressure on between them and the RO shot up to 70. I had a spare sediment filter so I replaced that filter and put the carbon block back in. Now I have 45 psi between the prefilters and the membrane. Is that number ok?

Now my next question was going to be why did they burn out so fast, the incoming TDS is only 220. As I was working on this thing I noticed that even when I had all water production stopped I was still outputting waste water. I even left it on all night and checked it this morning after no water use and sure enough it was still outputting waste. Does that mean my auto shut off is bad? Also it appears my storage container needs to be repreassurized, could that cause any of these problems?

Thanks again for all your help.

superfirefly · 10/16/2010, 09:01 AM

I am still having some problems with this system. I replaced the sediment filter and now the pressure between the prefilters and the RO is between 40 and 45 (incoming pressure is between 70 and 80).

After I did that I noticed my storage tank was full but no water would come out. I checked the pressure on the tank and there was none. I pressurized the tank per the instructions to 7 psi.

Now the tank will not fill at all. I also get no ro water if I bypass the tank. I am getting plenty of waste water though. I know I need to replace the rest of my prefilters but I still have 40 after them which I assume is enough that I should still see some water production, correct? Does this mean my RO membrane is bad (I just replaced it in the last few months)

Also with all output vales turned off I am still seeing waste water production. Do I need to replace the auto shutoff is bad or is it still running because the filters are clogged?

Thanks again for any help.

10/12/2010, 05:38 PM	#1
superfirefly Registered Member Join Date: May 2005 Location: St. Charles, Missouri Posts: 560	RO/DI filter help I have an old water general system that has been running great for almost 5 years. At the begging of the summer my out put slowed to barely a drip a second. At that point I replaced all filter and RO membrane. It was better for a month or so now it is back to a drip every few seconds. I just got a pressure gauge and I am trying to figure out what the numbers mean. If I disconnect the input line from the unit and dead end it into a pressure gauge I get between 70 and 80 PSI. I then dead ended it on the output of my 3 filters. I got 70 PSI. Next I put it inline between the 3 filters and the RO/DI, I get 12. It doesn't matter if I have the unit wide open or turned off. That number doesn't change. Does that mean I have problems with my membrane? Thanks for any help.

10/12/2010, 10:00 PM	#8
jjstecchino Registered Member Join Date: Jan 2009 Location: South Carolina, USA Posts: 409	You may have a problem with clogged prefilters. Keep in mind that what matters is the pressure of the flowing water, not the static pressure of the water not running. Let me explain with an example: If the prefilters are clogged and let only a trickle of water through, this will cause a significant pressure drop just before the membrane and the membrane will produce very little water. On the other hand if the water production is shut off, slowly the pressure after the prefilters will rise to the nominal pressure of the household water supply. From what you describe my bet would be that the prefilters are clogged. If you have a standard setup with a 5 micron filter followed by a 5 micron carbon block, followed by the 1 micron carbon block, usually this last filter is the one that clogs the most. You can test the system by removing the 1 micron carbon block from the canister and if water production goesup topar,replace the filter. It does not sound you have a problem with the restrictor. __________________ Claudio Click on my username and 'Visit jjstecchino's homepage!" to view my 180 gallon reef build thread. Current Tank Info: 180 Gallon Reef in Infancy

10/14/2010, 10:00 AM	#9
superfirefly Registered Member Join Date: May 2005 Location: St. Charles, Missouri Posts: 560	Thanks for the top jjstecchino, you were correct. As soon as I removed that last filter the pressure on between them and the RO shot up to 70. I had a spare sediment filter so I replaced that filter and put the carbon block back in. Now I have 45 psi between the prefilters and the membrane. Is that number ok? Now my next question was going to be why did they burn out so fast, the incoming TDS is only 220. As I was working on this thing I noticed that even when I had all water production stopped I was still outputting waste water. I even left it on all night and checked it this morning after no water use and sure enough it was still outputting waste. Does that mean my auto shut off is bad? Also it appears my storage container needs to be repreassurized, could that cause any of these problems? Thanks again for all your help. Last edited by superfirefly; 10/14/2010 at 10:11 AM.

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10/12/2010, 06:00 PM	#2
JEFFRO33 Registered Member Join Date: Oct 2008 Location: CENTRAL JERSEY Posts: 69	Ro/di will only produce water drop by drop.You may want to check the pressure in the storage tank.Make sure there is no water in the tank when checking.You should have a reading of 7psi on a empty storage tank.If not repressurize it.Hope this helps!

10/12/2010, 06:18 PM	#3
superfirefly Registered Member Join Date: May 2005 Location: St. Charles, Missouri Posts: 560	I have the storage tank turned off for my testing. I know what you mean by drip by drip but I am not even getting that. I left it on for 18 hours and only 1/4 filled a 20G brute trash can. After totally disassembling the unit and doing some more research I am thinking it is the flow restrictor. Does that make sense?

10/12/2010, 06:42 PM	#5
superfirefly Registered Member Join Date: May 2005 Location: St. Charles, Missouri Posts: 560	After reseating the ro membrane I am now getting 25 PSI and a steady drip. Does that sound right or should the pressure be higher?

10/12/2010, 07:52 PM	#6
JEFFRO33 Registered Member Join Date: Oct 2008 Location: CENTRAL JERSEY Posts: 69	A steady drip sounds about right.Check with a tds meter and compare to the untreated water.

10/12/2010, 09:13 PM	#7
superfirefly Registered Member Join Date: May 2005 Location: St. Charles, Missouri Posts: 560	Well my steady drip is now gone and the system is reading 12 PSI again. I think I will try a new flow restrictor since the one I have is known to have problems.

10/16/2010, 09:01 AM	#10
superfirefly Registered Member Join Date: May 2005 Location: St. Charles, Missouri Posts: 560	I am still having some problems with this system. I replaced the sediment filter and now the pressure between the prefilters and the RO is between 40 and 45 (incoming pressure is between 70 and 80). After I did that I noticed my storage tank was full but no water would come out. I checked the pressure on the tank and there was none. I pressurized the tank per the instructions to 7 psi. Now the tank will not fill at all. I also get no ro water if I bypass the tank. I am getting plenty of waste water though. I know I need to replace the rest of my prefilters but I still have 40 after them which I assume is enough that I should still see some water production, correct? Does this mean my RO membrane is bad (I just replaced it in the last few months) Also with all output vales turned off I am still seeing waste water production. Do I need to replace the auto shutoff is bad or is it still running because the filters are clogged? Thanks again for any help.