RO systems & flow restrictors

[Doug]

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.

[banditpowdercoat]

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.

[Doug]

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?

[mark]

DIY mixing valve?

Won't need something fancy (as for a eye wash station with a fixed temperature complete with recirculation pump), but could you tap into the hot and cold lines, valve on each for some adjustment, Tee, then ro unit?

My Dad had something this for years connected to a outdoor tap so he could rinse the dog (old dog) with warm water.