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Need new ro system

R

RAATCB

Member
Looking to purchase a new RO system. When busy It seems that my current RO system output is not enough to keep up with demand.


My current specs & plumbing:

3/4 feed into Unit that supplies @ least 8 to 10gpm
Product line - 1/2
Reject line - 1/2
Electrical - 20 amp 1 phase outlet.

Can anyone recommend a solid system that will last with trouble free issues? Also if anything goes wrong with unit parts are available and easy to service.
 
How many and what size are the RO membranes? If you have a typical one membrane of 4" diameter and 40" long, it will produce one GPM, or 1,440 gallons per day. If it's not producing that you might just need a new membrane. If it is making that you can just add a bigger storage tank for a lot less money.
 
Add more membranes and vessles. We started with two which failed miserably to keep up. Added a third and now a forth membrane to the same system, we now get 4-5 gpm depending on water temp.

Make sure you run warm water, I have a blend valve set at 110 for maximum output. If it were only cold water it would put out about 2.5 gpm max at 50-60°

Try to keep the pressure at 200 or less or keep the product water flow in proper relation to permeate. Otherwise you'll foul prematurely. (Cold water will raise the pressure)

The only thing that really matters is the number of membranes and temperature of water.. No matter what system.

Unless you don't have a boost pump that's good or capable there should be no reason to have to buy new.. The boost pump at 10gpm can support 4 membranes. But of course a new ro could be nice if you've got the cash., one with automatic RO water flush of the membranes for example. A feature I don't have but make it along just fine with proper adjustments, and chemical cleaning every year or two depending on how the softeners have been working.
 
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An efficient RO system will recirculate a portion of the reject to keep the product/reject ratio at 1:1. The water moving faster through the membrane also slightly improves production. Ideally you want to move about three times the volume of water through the membrane as it's rated to produce. If your system is good overall aside from not keeping up, consider adding a bigger pump/motor and plumb it to be more efficient. You may not need to replace it.
 
My current ro specs are: 3600 gpd unit with procon series 5 pump (4gpm max volume) with 1 hp motor with 2 (4x40) TFC membranes

The way the product/reject 1:1 (50%) recovery. But on the unit there is no reject regulator, the way it's set up by factory is there is a small tip fitting that automatic rejects a portion so it cannot be adjusted, it is set.

I still do not understand how I use to achieve 2.5gpm product and now with new membranes and procon pump, it will not exceed 1.5 gpm.

I have ben scratching my head for the pass 4 days.
 
yeah 4gpm is barely enough for two membranes imo. My specs are 3 times the permeate for two membranes. Going less increases fouling.

Temperature is everything! There is near 100% increase in production from cold to 110 hot . Check your water heater and temp at the inlet. it sounds like it may be different and would explain it. If the inlet is cold your not getting near the production you should.

Otherwise something else is causing low production, is the pressure still the same or is the pump going bad? Flow rates still the same? Do you have lower inlet flow than before?

Mine just has Barb for recirc too.
 
mrfixit said:
yeah 4gpm is barely enough for two membranes imo. My specs are 3 times the permeate for two membranes. Going less increases fouling.

Temperature is everything! There is near 100% increase in production from cold to 110 hot . Check your water heater and temp at the inlet. it sounds like it may be different and would explain it. If the inlet is cold your not getting near the production you should.

Otherwise something else is causing low production, is the pressure still the same or is the pump going bad? Flow rates still the same? Do you have lower inlet flow than before?

Mine just has Barb for recirc too.
Click to expand...

The procon pump is brand new. Membranes are about a year old. Inlet flow has no restriction.
 
Membranes are fouled. Guaranteed.

Probably from low flow I suspect. You can clean them and restore possibly to 95% of ne depending on the fouling agent. . Its not that hard or expensive. 10.00 max and less than half a day of time. I've restored many with cleaning.

Only other thing it could be is temprature.

So i take it your fed up with this little system. A system with a 10gpm boost pump will allow you to go up to 4 membranes if needed. Look for one that flushes with permeate automatically . sorry can't recommend any I just keep mine going.
 
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mrfixit said:
Membranes are fouled. Guaranteed.

Probably from low flow I suspect. You can clean them and restore possibly to 95% of ne depending on the fouling agent. . Its not that hard or expensive. 10.00 max and less than half a day of time. I've restored many with cleaning.

Only other thing it could be is temprature.

So i take it your fed up with this little system. A system with a 10gpm boost pump will allow you to go up to 4 membranes if needed. Look for one that flushes with permeate automatically . sorry can't recommend any I just keep mine going.
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My membranes are only 1 year old. I had a local company install the membranes and over charged me for them. They only took out the old membranes and put the new ones in. They did not clean the vessel or anything.

I do not understand that my old membranes lasted over 5 years and now how can the new membranes go out that fast? The water flow has been always the same.
 
Its not hard to foul a membrane in 3 months if you want. Something has changed... Someone may have set the flow rates too aggressive... Even your incoming water from the city could have changed. Water quality is a main factor in membrane performance.

Do you have softeners? Have you tested ro inlet water for hardness, tds, and chlorine? What's the hardness of the incoming fresh water at your site? Chlorine? What major contaminates are visable in your systems? Have you seen an increase in rust/ iron?? Do you know the iron levels?

Do you know if the vessles were coated with rust or free iron? Or what was showing built up on walls of vessles. Orgainics? Slime?

You'd hate to put a new system in and foul those membranes too.
 
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I watched someone jack with his softener and managed to get brine in the lines. The RO instantly dropped to about half the rate it was making and no amount of flushing restored it.
 
Yeah it can literally happen that quick.

I would have tried a chemical cleaning if the time allowed, I've had a lot of good luck cleaning them. Just choose the appropriate chemical for the flouing agent. Round here its calcium, lime, and rust. Dilute Clr or limeaway works wonders in a recirculation & soaking process for those contaminates, clr may remove sodium too.

Last time I did a set with 3 severly fouled membranes, it went from ~1.3g to about 3.5g permeate after cleaning restored to about 95%+. They're still going after another year with no degredation in quality or output... But this is usually only something an owner would do because its a bit of work and takes a while with the soaking for a few hours and swapping to a fresh solution half way... 600-700 for 3 new membranes, or 6 hours to set everything up and complete the cleaning job... I just wonder how many have been tossed that could still be in use today.
.

Sooner, you should have a prefilter housing to catch that stuff. Otherwise the membranes have thier own filter screening as well, that can get clogged with heavy debris if it gets by the filter. If the membranes are running at proper osmotic pressure, major water comtaminates that make it through the screen should pass along the surface through to reject. Over pressurizing them causes the flow to reduce and heavier contaminates to be forced into the membrane.

The best thing to do is pull the vessel plug and see what it looks like at the membrane caps to get an idea of what your dealing with.

There are many different types of water across the country, they can cause different problems for the membrane.
 
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What exactly is the vessel plug? How can I tell if my membranes are too clogged up? I have done a time measure, & I am getting about 300gpd (instead of the 600gpd that it's rated for).
 
You should have two flow meters that will show live input / output. If set at recommended flow levels the permeate will be low and you won't be able to reach the the correct flow offset.. Increasing pressure increases the permeate but will also add further to the fouling because your reducing the input/discharge flow. The high flow keeps heavies suspended and rolling off the membrane, not being forced in.

The end of the vessels have endcaps (plugs) that hoses are connected to, usually one at least. Pull the pins, clamps whatever and you can pull it out, some can be really really tight and a pain to get out. Just keep working it slowly.

Once that's off you'll see the top of the membrane end cap. You can carefully pull the membrane out, sometimes its really stuck too. Take it easy. Mine is usually rusty looking cause its my main issue. Sometimes you can tell they are really heavy with minerals when you pull it.. If its bloated looking down the sides, it is shot and blew the film.

*
Temprature first. Make sure any output / performance levels are compared at similar temperatures. As cold to hot is about double. Most membranes are rated to 120°. I shoot for 110 to be safe as it will go high sometimes. 130° is the max and reaching damage zone of melting the film if it goes any higher.

I did have to put a blend valve for hot and cold a few years after the wash was built. The temp would spike to 130+ too much. Fried the membrane, output gets a high tds when that happens usually.

I should start a membrane cleaning thread as it seems to be a dieing art. :) lol
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Raatcb.

The ginsan systems kleen rite has look good. All the features you would want for the most part. Option for auto or manual Permeate flush, inline tds standard. Ect.

I would avoid pvc vessels they eventually can crack. All mine are now stainless and one fiberglass which is solid
 
I don't like the PVC ones either. I remember working on a wash where every time the RO unit came on the vessel creaked as it came up to pressure.

The stainless ones aren't much more expensive and are usually easier to open for service.
 
MEP001 said:
I don't like the PVC ones either. I remember working on a wash where every time the RO unit came on the vessel creaked as it came up to pressure.

The stainless ones aren't much more expensive and are usually easier to open for service.
Click to expand...

My vessels are made by codeline (40E30N) 4''-40''. The vessel seems ok but the only thing I do not like it removing the ring that holds the cap.

I personally like the stainless vessels clamp mounted, its easy to loosen and swap membranes. I was talking with a friend and he said make sure you buy the vessels made in the USA because the imports might not fit 100% and will have problems later. Is that possible?
I see stainless vessels for $100 each to $200 each.
 
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