POSSIBLE CAUSE
Incoming water temperature is cold.
Incoming water has extremely high level
of Total Dissolved Solids (TDS).
Low incoming water pressure.
Feed water valve is plugged or closed.
Carbon pre-filter is clogged.
Reverse Osmosis Membrane is fouled.
Air pressure in holding tank is incorrect.
Air bladder in holding tank is ruptured.
No water to drain. Drain flow restrictor
is clogged.
No water to drain. Air gap faucet is
clogged.
Check valve on RO Membrane Housing
is stuck.
The automatic shut-off valve is
malfunctioning.
POSSIBLE CAUSE
Air pressure in holding tank is incorrect.
(THIS IS THE #1 REASON FOR LOW
FLOW FROM REVERSE OSMOSIS
FAUCET)
Carbon post-filter is clogged.
Heavy water use. Holding tank is empty.
Low Water Production.
USS-335 installation instructions
Low Water Quantity
SOLUTION
The water temperature is one of the key factors in the performance of the RO membrane. The
higher the temperature, the higher the flow rate, and vice versa. All RO Membrane elements are
tested and rated at 77° Fahrenheit. Ensure the RO is installed in a heated area of the home.
Incoming TDS Level is one of the key factors determining the flow rate of the RO membrane.
More TDS requires more time for the membrane to remove - no solution is required. Ensure
incoming TDS does not exceed 2000 ppm.
Incoming water pressure is one of the key factors determining the flow rate of the RO membrane.
Higher pressure will enable a higher flow rate. Pressure must be above 40 PSI for proper
operation. You may need to install a Booster Pump if your pressure is below 40 PSI.
Open valve or unclog.
model number USF-201.
Replace filter with Brita
®
Make sure incoming water pressure is within operating limits. Make sure drain line is not clogged.
Correct cause of fouling or replace RO membrane.
Empty water from holding tank. Air pressure in valve stem should be between 5-7 PSI. Increase
PSI similar to adding air to bicycle tire.
Replace holding tank. Call Customer Service for replacement.
Remove tubing from membrane drain port, cut 1" length off end of tubing and add new restrictor.
Remove faucet body from faucet base and disconnect drain 3/8" tubing. Ensure the drain
connector is properly aligned with the hole in the drain pipe. Ensure there are no obstructions -
clear them out. Remove faucet body from faucet base and disconnect air gap 1/4" tubing. Ensure
there are no obstructions - clear them out. Replace Air Gap Faucet.
Replace whole check valve assembly. Refer to maintenance section.
Replace automatic shut-off valve. Refer to maintenance section.
Low Water Pressure from Dispensing Faucet
SOLUTION
Open faucet and empty water from holding tank. Shut off feed water to system and remove
holding tank from under sink (the tank is easier to work on). Locate the air valve stem (just like
on a car or bicycle tire) and add air. If there is still water in the tank, continue to add air until all
the water is removed. Once all the water is removed, continue to add air and pressurize to 5-7 psi.
Reinstall the tank under the sink, turn on the feed supply to the system and allow the tank to fill.
Replace post-filter with Brita
Redi-Twist™ USF-201.
®
Allow holding tank to refill.
See previous section on Low Quantity of Water from Holding Tank.
connect to auxiliary faucet
Troubleshooting
Guide
Version 2.1I
23