RO systems & flow restrictors
 

I purchased a Vectapure RO system and took it up north when I went for Christmas. Its a complete under sink install.

So the waste line also taps into the sink drain line. I have never used one this way, as ours have always drained into the washer stack. Anyways the waste line had a flow restrictor in it. Just a little insert in the line itself. All my drain lines have been wide open. Anyone else seen these?

Whats a normal waste ratio? Would it be 3-1, meaning wasting 3g of water to produce 1. Seems much to high for me but never checked into it myself?

A membrane needs some sort of restriction for work if not the water isn't forced through it.

I got the Aquasafe and comes standard with a flush valve/flow restrictor, additionally from them I've gotten a variable flow restrictor that I've put after the flush valve/flow restrictor and adjust it for the common 4g (waste):1g (good) ratio.

My flow restrictor is in the waste line where the line attaches to the last filter cartridge which in my case is the DI.

I think 3g waste per 1g good water is too good to be true. I think mine is more like 4:1 or even 5:1, but I've never officially measured it.

Hi Mark. Guess thats where mine is also, as I have the flush valve on mine. This unit has a Santi-Purge valve on it, which I guess is similar but not the same as it allows water in the system to purge it with chlorine. http://www.waterite.com/main.html

So the inline restrictor must be needed then. I wonder if it matters which end of the waste line its in. Inst. said on the drain pipe end but I think we have it on the membrane outlet end. Cant see it being directional just a restriction?

Geez, all the others I have put in are simple to use.

Why is the waste line going to the DI ? Do not all waste lines go down the sink or where ever?

Looks like your purge valve has a different function than my flush valve, seems yours will run tap water downstream to your membrane (I'm assuming no DI). What the flush valve does is in the closed position provides a fixed restriction on the waste line, in the open position there's no restriction and water just flows past the membrane to clear it. Thought the fixed valve gives close to 4:1 with the variable valve I can get the ration to 1:1 though at the cost to the life of the membrane.

For the ro, mine has 1 input and 2 outlets (filtered and waste), the resistor is on the waste line (diagram)

Ok, I see how the flush valve restriction works. Thats how my own unit works then and why my drain line is wide open in the end, as compared with the other unit. Thanks.

Thats interesting.

Whoops. Right on. I was just going to ask you that. Must have missed it first read.

So, we have the flow restrictor think worked out. However the unit cant seem to make much water. Very slow. Yesterday he said it took 1.5hr. to make a liter, then when he tried to measure 2 liters, it was still running 5 hrs. later.

Pressure bladder from his well runs at 40psi which seems not bad. Wondering if the very cold well water is the main culprit, even though it passes through the softener first. Also wondering if the ro 3g holding tank pressure bladder has to much air in it, that would not let it fill correctly? Unfortunately his current air pressure measuring devices dont read below 10 psi.

Pressure and cold really affect the speed of RO water. Im running approx 70psi here at my house, and with cold water, I get 40gpd or so. It's a 50GPD membrane and restrictor. Most RO systems are rated at 72*F water and 65-70PSI I think. Higher water temps really increase the filtered water output of my system. It's a Kent RO/DI unit I have, but they are all pretty much the same.

Thanks Dan. So @ 40psi, he is pretty low and along with the cold water, bad water making.

I was reading the ro thread on heating the water in the main forum but thats a reefing application. Anyone have any ideas for a typical under the sink unit. Perhaps we should draw the water someplace else so it can be heated somewhat bu the time it gets to the ro but then I,m guessing we need a booster pump, which it look like may be needed anyways.

Or the variable restrictor Mark mentioned?