RO System FAQ
Generally, problems of a RO system can be divided into 3 categories: pressure, flow and salt rejection. The following lists of questions help to identify possible causes for these problems.
Pressure
Why operating pressure is low?
Possible causes
- Insufficient feed water pressure or flow
- Pre-filter clogged
- Solenoid valve not open
- Pump rotating backwards
- Insufficient power supply
Why operating pressure is high?
Possible causes
- Concentrate or recycle valve plugged
- Membrane fouled
- -Membrane install backward
- Feed water throttling valve closed or restricted flow
Why excessive pressure drop (high primary pressure, low final pressure)?
Possible causes
- Restricted flow after pump discharge
- Membrane severely fouled
Flow
Why permeate flow is low?
Possible causes
- Low operating pressure
- Membrane fouled
- Operating on cold water
- Flow meter inaccurate
- RO system was shut down without flushing
- Pre-filter clogged
Why concentrate flow is low?
Possible causes
- Concentrate valve plugged
- Concentrate pipeline restricted
- Membrane damaged or rupture
Why water keeps flowing when machine is turned off?
Possible cause
- Inlet solenoid valve not, closing or seating properly
Salt Rejection
Why permeate conductivity reading is high?
Possible causes
- Membrane fouled
- Membrane seal o-ring broken or damaged
- Raw water quality changed
- Membrane exposed to chlorine or other strong oxidant
- Fouled probe or inaccurate conductivity monitor