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Low water flow RO filters - Tank Pressure Problem
Last Updated: 03/04/2013
The number one reason for low water flow from a reverse osmosis system is low air pressure in the holding tank.

The Problem: Low Volume and Poor Pressure
Little to No air pressure will result in very little water being pushed out of the holding tank. You will have a full and heavy holding tank, but with out the air pressure, you'll never get much water out of the tank. Too much air pressure ( say over 10 psi on a small tank ) will result in good water flow but will severely limit the amount of water that can be stored in the holding tank. So, it is recommended to put 8 psi of air in your under the sink reverse osmosis holding tank. If you get water coming out of the air valve, then it is time to purchase a new holding tank.

To Check:
With all possible water drained from the holding tank, you want to get an air pressure reading of 8 PSI of air pressure. There is a "tire" valve on your holding tank somewhere ( usually the bottom ). You really should use a special low pressure air gauge.
One that shows the air pressure in one pound increments starting with one pound. The average tire gauge starts at 5 or 10 lbs. psi.

If the tank will not hold air pressure, or if water comes out the air valve stem, then the tank ( RO Storage Tank ) will need to be replaced with a new one.
See:Replacement RO Tank

To see how > Youtube Video about Adding Air to Tank

Refill RO storage Tank time question:
**** If your Membrane is 50 gpd ( gallons per day ) then it makes about 1 - 2 gallons of water per hour....
It's rated to make 2 gallons per hour, but that is only if your water pressure is at least 60 psi, and the water temperature is at least 77 degrees.
Less pressure or lower temperature will slow the production rate of the membrane.

So, give the unit 3 - 6 hours to refill and shut off.

And if you have an older 25 gpd TFC or 14 gpd CTA membrane expect it to take a lot long to fill an Empty Tank, before the system will "shut off" and stop making water.

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