RODI question, I'm a RODI newb...

Hi,

I got a Kent RODI off of craigslist. The guy who sold it to me had it seemingly hooked up wrong, with the water line going into the charcoal, then into the membrane and then into the micron and resin filters.

So I have zero idea what I'm doing, but I found a diagram and hooked it up in the same way - but no water is flowing through this thing. It's pathetic. I bet I don't get a whole gallon within a single day.

There are some really basic RODI questions that I can't find answers to. Specifically:

When a membrane wears out, does it get slower?
Does the ordering of the filters cause problems with the membrane?
How long do membranes last?

The model that I got supposedly does a max of 20gpd (from what the guy who sold it to me said) - but it looks exactly like the 24gpd model that is sold here:

TFC RO Filter 24 GPD (Kent)

The guy added a 4th stage resin filter (but again, had it seemingly hooked up wrong).

I can't find instructions, manuals, or even a phone number for Kent.

Any advice is appreciated

 

Kent Marine » Tech Support

 

Most of the time it clogs and runs slower. It can rupture and cause high TDS.

Most definitely. You want micron, carbon, membrane then resin in that order.

Depends on your water quality and how well you maintain the micron and carbon filters. It also helps to backflush the membrane. It should last a couple of years at least. Your's is bad since the micron filter was after the membrane.

Do you have good water pressure going into the RODI? You need good strong input pressure to work correctly.

Jack

 

RO membrane output is mostly dependent on two things, tap water pressure and tap water temperature, those are the two main ones. There are also other factors such as waste ratio and incoming TDS that have some effect too.

Do you know your water pressure? Do you know your water temperature?
To get anywhere near 24 GPD out of that system you need 60-65 psi water pressure and 77 degrees F water temperature and a maximum of 250 ppm TDS in your tap water. The waste ratio, which is the amount of water coming out of the waste line in comparison to the good or RO/DI water line should be 4:1 or 4 ounces/cups/ gallons, whatever, of waste in the same amount of time as one of those same units of measurement comes out of the good line.

Right off the bat, my first question is do you have a flow restrictor in the waste line and is it somewhere cloes to 4 times the flow as the good line?
Next you need the temperature and pressure numbers and your TDS to troubleshoot the system. I'll bet we can get it figured out pretty easily if you can provide those numbers. A photo of how you have it plumbed would also be helpful since it is very easy to get lines crosed up, even for old timers like myself.
I can also provide you some very easy to understand drawings and troubleshooting instructions if you would like.