OT?: RODI Help

truebeliever71

truebeliever71

Premium Member
I'm having a problem with my RODI unit and am a bit puzzled with what the problem is. I'm only getting a trickle of water out of the pure water line but the normal flow out of the waste water. About 6 months ago I replaced all of the cartridges, and flow restricter. The restricter does have a flush valve which I use for about 15 mins every couple months.

Any ideas as to what the problem could be?
 
Have you verified the product water ratio?

What's your incoming water pressure and temperature like?

Can you post the brand/model of membrane and which flow restrictor you're using?

Do you have any "weird" conditions - really long tubing runs, fittings, valves, etc. on either the product or waste water lines?
 
I'm using the 150GPD 6-stage 1:1 unit from purewaterclub. I have had it for about 3 years. Normal water pressure is around 40psi and I'm running a booster to get it around 65psi.

The filter replacements came from purewaterclub.com where I originally purchased the filter.

I am wondering if the problem could be with the auto shutoff? That is the only thing I didn't replace. If it is, would there by any harm to just removing it all together since I manually shut off the filter anyway?
 
You can definitely remove the auto shutoff if you're manually shutting it off.

Really, product ratio is determined by only a few things:

1) Membrane
2) incoming water pressure and temperature
3) flow restrictions on either line (either "on purpose" via flow restrictor or "by accident" via valves, fittings, and so on).

I'd also double check obvious things, like membrane not aligned properly in the canister, obstructions in the plumbing or fittings, and so on...

Where on the unit is your pressure reading coming from? If it's before the prefilters can you take a pressure reading right on the inlet to the RO membrane?
 
I have checked the lines and fittings. I'm a little hesitant about the membrane as I have to really mess it up to get it out of the housing.

Something else I just thought of is that in our new house we have a water softener and I have the filter downline from it. Could that be causing problems?
 
Essentially, low temperatures throw off production rates. Hot temperatures will destroy the membrane (which, of course, will also throw off production rates, as well as water quality).

Membranes are spec'd with acceptable temperature ratings if you want to know the exact details. Sometimes it's right on the membrane, other times you have to look for a datasheet. Membrane performance is also typically quoted at a specific temperature (i.e. the common 75gpd Filmtec membrane is quoted at 77 degrees).

Residential hot water is generally way too hot for a membrane (it'll kill it) so most people run off their cold water line. However, most residential cold water supplies are way too cold to get the specified performance. So, some people try to find a solution - typically either mixing hot and cold with a mixing valve, or putting the RO/DI unit or a coil of line on the input side in a vat of water heated by an aquarium heater, or something else similar.
 
truebeliever71 said:
Something else I just thought of is that in our new house we have a water softener and I have the filter downline from it. Could that be causing problems?
Click to expand...

That's way more likely to help rather than hurt, but it depends a bit on the specifics of the water supply. At any rate this would be the kind of thing to affect quality and lifespan, not flow rate.
 
der_wille_zur_macht said:
Essentially, low temperatures throw off production rates. Hot temperatures will destroy the membrane (which, of course, will also throw off production rates, as well as water quality).

Membranes are spec'd with acceptable temperature ratings if you want to know the exact details. Sometimes it's right on the membrane, other times you have to look for a datasheet. Membrane performance is also typically quoted at a specific temperature (i.e. the common 75gpd Filmtec membrane is quoted at 77 degrees).

Residential hot water is generally way too hot for a membrane (it'll kill it) so most people run off their cold water line. However, most residential cold water supplies are way too cold to get the specified performance. So, some people try to find a solution - typically either mixing hot and cold with a mixing valve, or putting the RO/DI unit or a coil of line on the input side in a vat of water heated by an aquarium heater, or something else similar.
Click to expand...

So, with the sudden cold snap with have in NY (at least here in the Binghamton area) do you think it would effect the production of water by that much? Normally it's good stream that comes out of the pure water line, now it's a few drips.
 
Hard to say without knowing how it affected your incoming water temp. Can you get a reading on the water temp being supplied to the unit?

And yeah, talk about cold snap. It was 12 below up here last weekend, and only 8 this morning.
 
This is just strange. I usually "make water about once a week; fill the Brute garbage can for the tanks and a couple bottles for the water cooler. Everything has been working great with the TDS between 3 and 4. Incoming TDS is around 275 (use to be over 500 at my old place.)
 
I have the same problem with the cold temps, my 75 gallon per day unit is easily cut in half. I only have mine hooked up to the cold water, it is very cold water right now....
 
sd2127 said:
I have the same problem with the cold temps, my 75 gallon per day unit is easily cut in half. I only have mine hooked up to the cold water, it is very cold water right now....
Click to expand...

Mine is being effected by more than that. 150GPD to 1 drop or 2 per second.
 
So, I removed the auto shutoff and it improved a little bit but not great. Pulled the RO membrane and rinsed out the canister and all of the sudden heard some air moving in the line. Hooked everything up (minus the shutoff) and it's working great! Eventually I'm going to get a float shutoff for the Brute can and will put a new auto shutoff on... but for now I'm good.
 
Sounds like you had a blockage or the membrane wasn't engaged properly. Congrats on fixing it. :)

Still might be worth checking the temperature if you're after optimal performance.
 
I think it was a blockage... but how? The water passes through 3 filters before it gets to the membrane. Ooh well, at least it's working and working good even without the booster.
 
Who knows? Bit of packaging material or something like that? Debris that got in when you were changing the filters? Dust/gunk/particles that washed out of the prefilters? I agree it's odd...
 
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