Reverse Osmosis Troubleshooting Guide

by Complete Water Solutions

*Warning – This guide can assist you help you to diagnose and trouble shoot your Reverse Osmosis System. For issues that are persistent or are not understood you should contact Complete Water Solutions and speak with one of our RO Certified Technicians. Please make sure when you call that you have the following information:

  • Machine Installation Date
  • Model Number
  • Serial Number
  • Detailed description of the problem.

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Reverse Osmosis Troubleshooting Guide
PROBLEM POSSIBLE CAUSES REMEDIES
Low Operating Pressure Insufficient feed water pressure or flow Open feed water valve. Check feed water valve for restrictions in feed plumbing
Clogged pre-filter cartridge Replace pre-filter cartridge
Dirty or fouled membrane elements Flush and/or clean RO System
Inlet solenoid valve no opening Verify valve receiving power when machine is ON. Clean or replace solenoid valve
Insufficient power Verify proper voltage is pre-sent. Check fuses and circuit breaker
Pump or Motor Not Operating Correctly Contact Complete Water Solutions for replacement or repair of pump or motor
Concentrate or Recycle Valve Open To Far Refer to maintenance manual to properly set concentrate and recycle valves
Low Permeate Production Low operating pressure (see above)
Machine operating on cold water Check the water temperature. If needed, install a hot/cold tempering valve. Permeate production rate is dependent on 77°F (25°C) Contact Complete Water Solutions for further options.
Membrane elements installed incorrectly For correct membrane element installation procedure refer to your Maintenance manual. For further assistance contact Complete Water Solutions.
Brine seal has “rolled” or been damaged Refer to maintenance manual membrane installation. For further assistance contact Complete Water Solutions.
Dirty or fouled membrane elements Flush and/or clean RO System
Back pressure on the permeate line Reduce permeate line back pressure. Check for restrictions in permeate plumbing
Useful life of membrane element(s) expired Install new membrane elements. Contact Complete Water Solutions for part # and order
Inaccurate permeate flow meter Check the flow rate manually with a stop watch and calibrate if necessary
Low concentrate flow with normal or high operating pressure Dirty or fouled membrane elements Flush and/or clean RO System
High Permeate Conductivity on RO System O-rings on membrane element(s) unseated or damaged parts Replace the O-Rings, check the sealing surfaces on the O-Ring groove end caps. Replace damaged parts.
Useful life of membrane element(s) expired Install new membrane elements. Contact Complete Water Solutions for part # and order
Change in incoming water quality Calibrate the meter with a DS standard solution or check the readings with another conductivity meter. Replace or clean probe. Check the connections between the probes and monitor.
ON/OFF Switch On: machine not running No Power To Machine Ensure machine is plugged in
Pressurized storage switch or storage tank float switch cut power to machine The storage tank may be full. The switch control may require adjustment
Thermal overload of motor Allow the machine to cool. Check the Amp draw to the machine
Pump motor failure Check the fuses or circuit breakers; measure the voltage. Contact Complete Water Solutions for service
Pressure does not drop when concentrate valve opened Dirty concentrate valve Disconnect and clean the concentrate valve
Excessive pressure drop across RO Membrane(s) Restricted flow after pump outlet Check for blockage of the concentrate flow at the inlets and outlets of membrane housings
Telescoped membrane element covering membrane housing Ensure that the anti-telescoping device (ATD) is intact
Fouled or dirty RO membrane elements Flush and/or clean RO System
Flow through machine while power is OFF Inlet solenoid valve not fully closed Ensure valve is not getting any power when machine is OFF. Replace the inlet solenoid valve

Still having problems or questions? Contact Complete Water Solutions.

Call (855) 787-4200 or email info@complete-water.com.