USF RO ManualOMRX_6.pdf

USFilter 

10 Technology Drive 

Lowell, Massachusetts 01851 

Tel: (800) 875-7873 • Fax: (978) 441-6025 

Email: 

Lowell_TechSupport@USFilter.com 

Operation and 

Maintenance 

Manual 

for 

RX 

Med-RO Series 

Reverse Osmosis Systems 

Catalog # _______________________ 

Serial # ________________________ 

68/OMRX – Med-RO RX Manual 04/04 Rev. 6

CAUTION 

This System is for use in medical device applications and may not be 

modified, reconfigured, or used in a medical application other than that for 

which it is labeled. Modification of this system is a violation of federal law 

and will void all warranties. 

INDICATIONS 

Use of the US Filter Reverse Osmosis System is indicated when water for use in the preparation of 

dialysate fails to consistently meet the minimum requirements specified in the ANSI/AAMI approved 

Water Treatment Equipment for Hemodialysis Applications, RD-62:2001 and Canadian Standards 

Associations Z364.2.2. The US Filter Reverse Osmosis System may be used with any 

proportioning dialysis machine having a compatible water demand. 

CONTRAINDICATIONS 

There are no contraindications to reverse osmosis water treatment. 

CAUTIONS AND WARNINGS 

Procedures using the Reverse Osmosis System must be performed under the direction of a 

physician. 

Prior to operating or servicing this device, this manual must be read and understood. If something 

is not clear, call for assistance before proceeding. Keep this and other associated manuals for 

future reference and for new operators or qualified service personnel. 

All electrical work should be performed by a qualified electrician in accordance with the latest 

edition of the National Electrical Code, as well as local codes and regulations. 

To avoid electrical shock hazard, do not remove covers or panels when power is supplied to the 

device. Do not operate the device when covers or panels are removed. 

All plumbing must meet local codes and be performed by qualified technicians. Feed water must be 

from a potable source. A backflow preventer may be required. 

WARNING 

WARNING 

A faulty pump motor or wiring can be a serious shock hazard if it or 

surrounding water is accessible to human contact. To avoid this danger, 

DO NOT remove any grounding wire from the system. 

The Med-RO series RO systems are Class II medical devices in the United 

States and Class III in Canada designed to supply water for dialysis

applications. A warning alarm indicates an operational situation that could 

compromise a patient’s safety. DO NOT allow the unit to supply water to a 

dialysis application if the unit is in an alarm condition. 

DISCLAIMER STATEMENT 

This operation and maintenance manual is intended to be used with the component manufacturer 

literature provided in the Appendix. These manuals should provide complete and accurate 

information to meet your operating and/or service requirements based on the information available 

at the time of publication. However, USFilter assumes no responsibility for the technical content of 

the manufacturer literature. 

This manual should be read fully and understood before installation, operation or maintenance of 

the system is attempted. The information in this manual may not cover all operating details or 

variations or provide for all conditions in connection with installation, operation and maintenance. 

Should questions arise which are not answered specifically in this manual, contact the USFilter 

Technical Support Department at the phone number provided on the cover of this manual. 

USFilter reserves the right to make engineering refinements that may not be reflected in these 

manuals. The material in these manuals is for informational purposes and is subject to change 

without notice and should not be construed as a commitment by USFilter. USFilter assumes no 

responsibility for any errors that may appear in this document. This manual is believed to be 

complete and accurate at the time of publication. In no event shall USFilter be liable for incidental 

or consequential damages in connection with or arising from the use of this manual. 

WARNING 

The Med-RO series RO systems are registered medical devices. No enduser 

modifications to the unit should be made. 

©Copyright 2004 USFilter 

Printed in the United States of America. All rights reserved. 

THIS BOOK OR PARTS THEREOF MAY NOT BE REPRODUCED IN ANY FORM 

WITHOUT THE WRITTEN PERMISSION OF THE PUBLISHERS.

PROPRIETARY RIGHTS STATEMENT 

This manual discloses information in which USFilter has proprietary rights. Neither receipt nor 

possession of this manual confers or transfers any right to the client, and by its retention hereof, the 

client acknowledges that it will not reproduce or cause to be reproduced, in whole or in part, any 

such information except by written permission from USFilter. The client shall have the right to use 

and disclose to its employees the information contained herein for the purpose of operating and 

maintaining the USFilter equipment, and for no other purpose. 

In the event the content of this manual is altered or section/items are omitted during a reproduction, 

in whole or in part, and instructions or definitions within the reproduction result in personal injury to 

those who follow the altered instructions, the burden of responsibility for personal injury falls solely 

on the party who affects the reproduction. 

MANUAL USER’S GUIDE 

This manual describes the procedures necessary to install, operate, and maintain your USFilter 

Reverse Osmosis system. Please read this manual carefully before installing and operating your 

equipment. The equipment warranty may be voided if installation or operation instructions are not 

followed correctly. 

Warnings, Cautions, and Notes are used to attract attention to essential or critical information. 

Warnings and Cautions will appear before the text associated with them, and notes can appear 

either before or after associated text. 

WARNING 

CAUTION 

Warnings indicate condition, practices, or procedures which must be 

observed to avoid personal injury or fatalities. 

Cautions indicate a situation that may cause damage or destruction of 

equipment or may pose a long term health hazard. 

NOTE: Notes are used to add information, state exceptions, and point out areas that 

may be of greater interest or importance. 

EQUIPMENT SUPPORT 

USFilter continually strives to provide safe, efficient, trouble-free equipment using the optimum 

technology for your application. If problems should develop, USFilter’s worldwide network of 

technical support will be available to provide assistance. For service, sales, parts, or additional 

manual copies call your area representative or USFilter, Technical Support Department at the 

number provided on the cover of this manual.

TABLE OF CONTENTS 

SECTION DESCRIPTION PAGE 

1.0 INTRODUCTION 

1.1 System Function.................................................................................... 1-1 

1.2 Quality Assurance/Quality Control......................................................... 1-1 

1.3 Functions of the System Components................................................... 1-2 

2.0 SYSTEM INSTALLATION 

2.1 Precautions Before Installation.............................................................. 2-1 

2.2 Unpacking.............................................................................................. 2-1 

2.3 System Location .................................................................................... 2-1 

2.4 Power Requirements ............................................................................. 2-2 

2.5 Water Requirements.............................................................................. 2-2 

2.6 Product Line .......................................................................................... 2-2 

2.7 Reservoir (optional) ............................................................................... 2-2 

2.8 Accessory Sensors (Pretreat Interlock & Tank Level) ........................... 2-3 

2.9 Setting the Flush Cycle Time and Duration ........................................... 2-3 

2.10 Before Power Turn On........................................................................... 2-3 

2.11 Installation of Reverse Osmosis Membrane(s)...................................... 2-4 

3.0 OPERATING INSTRUCTIONS 

3.1 Controls and Indicators.......................................................................... 3-1 

3.2 Initial Startup of Reverse Osmosis System ........................................... 3-1 

3.3 Initial Flushing of the System................................................................. 3-2 

3.4 Normal Operations................................................................................. 3-2 

3.5 Shutdown (Less Than 4 Days) .............................................................. 3-4 

3.6 Long Term Shutdown Procedure........................................................... 3-4 

4.0 SYSTEM MAINTENANCE 

4.1 General.................................................................................................. 4-1 

4.2 Sanitizing the Reverse Osmosis System............................................... 4-1 

4.3 Cleaning the RO Membranes ................................................................ 4-5 

4.4 Maintenance Schedule ......................................................................... 4-9

TABLE OF CONTENTS 

SECTION DESCRIPTION PAGE 

5.0 TROUBLESHOOTING 

5.1 System Inoperative................................................................................ 5-1 

5.2 Low System Pressure............................................................................ 5-1 

5.3 Low Percent Recovery........................................................................... 5-1 

5.4 High Percent Recovery.......................................................................... 5-2 

5.5 Low Salt Rejection................................................................................. 5-2 

5.6 System Keeps Shutting Off.................................................................... 5-2 

5.7 System Shutoff, Low Pressure .............................................................. 5-2 

5.8 System Shutoff, High Temperature ....................................................... 5-3 

5.9 Low Product Flow Rate.......................................................................... 5-3 

5.10 Motor Overload Shutdown ..................................................................... 5-3 

5.11 Controller Malfunction............................................................................ 5-4 

6.0 WARRANTY 

6.1 General Limited Warranty...................................................................... 6-1 

6.2 Water System Limited Warranty ............................................................ 6-1 

7.0 APPENDIX 

7.1 Glossary of Terms ................................................................................. 7-1 

7.2 Replacement/Spare Parts List -- RX Model........................................... 7-2 

7.3 RO Data Collection Form....................................................................... 7-4 

7.4 QA Data Report ..................................................................................... 7-7 

7.5 Drawings................................................................................................ 7-8 

7.6 Component Manufacturers Literature.................................................... 7-9 

TABLE # DESCRIPTION PAGE 

4-1 Sanitization Times and Concentrations for Polyamide .......................... 4-2 

Thin Film Composite Membranes 

4-2 Cleaning Solutions for Polyamide.......................................................... 4-8 

Thin Film Composite Membranes

For Product and Service Information 

USFilter 

10 Technology Drive 

Lowell, MA 01851 

Telephone: (978) 934-9349 

FAX: (978) 441-6025 

For Technical Support 

Telephone: (800) 875-7873 Extension 5000 

Email: Lowell_TechSupport@USFilter.com

RX Manual 04/04 Rev. 6 INTRODUCTION 

1.0 INTRODUCTION 

Congratulations on your selection of this USFilter water purification system. This system is 

designed and manufactured to the highest standard of quality and fully tested and inspected 

prior to shipment. In order to get maximum performance, we ask you to read all of the following 

instructions before installing and operating this system. Any warranty offered will be void unless 

directions are followed exactly. 

This manual is divided into sections for easy reference. Review this manual thoroughly and 

then return to section 2.0 System Installation for step-by-step installation instructions. 

If you need technical assistance in operating or maintaining your USFilter unit, call your local 

representative. If you require further assistance call USFilter, Technical Support Department at 

the phone number provided on the cover of this manual. 

1.1 SYSTEM FUNCTION 

The function of a Reverse Osmosis (RO) system is to remove contaminants from a 

water supply using a Reverse Osmosis (RO) membrane. The system produces purified 

water that is low in inorganic salts, organic matter and bacteria. The purified water can 

be used as a direct feed to a distribution system or stored in a reservoir. 

RO systems operate on the principle of passing water through the membrane under 

high-pressure. Some of the water passes through the membrane and is purified 

(product or permeate), the remainder of the water containing the impurities (concentrate 

or reject) is not passed through the membrane and is diverted to drain. In addition, 

portions of the product and reject are returned (product and reject recirc or recirculation) 

upstream of the pump to improve the operation and productivity of the RO system. A 

single prefilter is used in all systems to reduce the amount of particulate contamination 

reaching the membranes. 

Please refer to the Product Description/Equipment Specifications in the Appendix for 

other parameters important to the operation of the system. 

1.2 QUALITY ASSURANCE/QUALITY CONTROL 

At USFilter we have defined Quality Assurance and Quality Control into a series of 

engineering and manufacturing practices and control procedures to insure that you, our 

customer, receive the finest product available in the world. We will continue to update 

these practices and procedures on an ongoing basis in an effort to improve our systems 

and to insure that they continue to reflect state-of-the-art technology and reliability. 

Quality assurance is the cornerstone of our quality program. It begins with the selection 

and qualification of components and materials. Before suppliers are selected, their 

products must meet or exceed rigid standards set by our Quality Assurance Department. 

From that point, our incoming material inspection insures only reliable components will 

be used to manufacture systems. Numerous checks are performed as the system 

passes through the manufacturing process. The completed system must pass a series 

of tests before release for shipment to insure the system meets technical and 

performance specifications. In the Appendix is a copy of our Quality Assurance Data 

Report for your system. 

Quality audits do not improve products. They do, however, insure that each system 

meets or exceeds specifications required for your application. 

USFilter 1-1


Customer feedback is also an important element of our program. Division heads meet 

on a routine basis to review customer feedback and initiate actions that result in process 

and product improvements. 

1.3 FUNCTIONS OF THE SYSTEM COMPONENTS 

Refer to the Process & Instrumentation Diagram (P&ID) in the Appendix. 

A. Low Feed Pressure Switch 

A low feed pressure switch protects the high-pressure pump. If the feed 

pressure to the pump falls below 15 psig the low feed pressure switch shuts the 

system down. The system will automatically restart four more times and if the 

low pressure situation has not been corrected after the fifth restart the system will 

remain shut down and will not restart until the alarm condition has been 

acknowledged and rectified. 

B. Reverse Osmosis Pump 

The RO system pump is a multiple stage centrifugal pump that is close coupled 

to an AC motor. The motor is a TEFC design and powered on and off through 

the controller by a motor starter. 

C. High Membrane Feed Pressure Switch 

A high membrane feed pressure switch protects the membranes and RO 

pressure vessels from potentially damaging pressures. If the membrane 

pressure exceeds the safe operating pressure for the pressure vessels and/or 

membranes, the high-pressure switch shuts the system down and requires 

operator intervention prior to restart. 

D. Reverse Osmosis Membranes 

The prefiltered water enters the RO pressure vessel and passes over the surface 

of an RO membrane. A portion of the feed water continues out of the system 

through the reject and reject-recycle needle valves; and is either directed to drain 

or just upstream of the pump to increase the feed flow rate. The remainder of the 

water permeates the membrane (product) and is directed to an accessory 

storage reservoir or point of use. Percent recovery (the ratio of RO product water 

to feedwater) will vary depending on water quality and the application. 

E. Reject / Reject Recirculation Throttle Valves 

The flow rates of water exiting the RO membranes are controlled by the reject 

and reject recirculation valves. Closing the reject valve increases the pressure to 

the membranes and reduces the amount of water to drain. Recycling a portion of 

the reject water permits part of the total reject flow to be returned upstream of the 

pump and can improve RO performance and production. Reject recirculation can 

be used to increase the overall recovery of the system up to the scaling limit. 

F. Product Recirculation Valve 

Product recirculation permits excess product water to be returned upstream of 

the pump. This function is used when capacity exceeds demand, thus 

conserving water and increasing percent rejection (water quality). 



G. Autoflush Valve 

In the TANK FEED and STANDBY modes, the controller automatically opens the 

autoflush solenoid valve (located in the reject piping) for a predetermined 

duration at a preset interval, bypassing the reject needle valve, thereby flushing 

the concentrate line in a high flow, low pressure condition. The duration and 

interval of this flush cycle is operator settable and is determined by the fouling 

characteristics of the feedwater. In the DIRECT FEED mode the autoflush 

function is inhibited. 

H. Controller 

The controller has the following capabilities (please refer to the component 

manufacturer literature located in the Appendix for a more detailed explanation of 

these features): 

1. Low-pressure shutdown - The pump motor is shut down when the feed 

water pressure falls below 15 psig. 

2. High-pressure shutdown – The pump motor is shutdown when the 

pressure to the membranes exceeds the set point to prevent damage to 

the RO pressure vessels, membranes or other components. 

3. High temperature shutdown - The pump motor is shut down on high feed 

water temperature to protect the RO membranes from exposure to 

damaging temperatures. 

4. Low percent rejection alarm - The alarm function is activated when the 

percent rejection falls below determined limits to warn the operator the 

product water quality no longer meets specifications. 

5. Pump startup delay - There is a fifteen-second delay after pressing the 

system start button before the pump starts. 

6. Autoflush - The system automatically flushes the reject piping for a user 

settable duration at a user settable interval when the system is in either 

the STANDBY or TANK FEED mode. 

7. Tank full shutdown - The system shuts down when the level switch 

(optional) indicates that the storage tank (optional) is full. Automatic 

restart occurs after either a predetermined interval or when the low-level 

tank switch is activated and the user settable delay has expired. 

8. Pretreatment Interlock - This feature stops the system when the 

pretreatment equipment is in the regeneration cycle and restarts the 

system automatically when the regeneration cycle is completed. 

I. Accessories 

The RO system can be used to feed a distribution loop, another piece of 

equipment directly, or an accessory reservoir. If an accessory reservoir is used, 

a level switch or level switches are necessary and the controller must be 

operated in the TANK FEED mode. These accessories are connected to the 

controller enclosure by wiring the electrical leads to the high tank level and mid 

tank level switch input connections. Optional terminals (pretreatment interlock) 

have been placed in the controller enclosure for shutdown by external signals. 

Normal operation will resume automatically when the pretreatment regeneration 

is completed. 



See the installation section for instructions on electrical connection of the 

accessories. 


RX Manual 04/04 Rev. 6 SYSTEM INSTALLATION 

2.0 SYSTEM INSTALLATION 

2.1 PRECAUTIONS BEFORE INSTALLATION 

The following are feed water source requirements: 

A. Inlet pressure of 35 to 80 psig at design feed flow. 

B. Designed operating temperature is from 25 °C (77 °F) to 45 °C (113 °F). Contact 

technical support at the number on the manual’s front cover if operation below 

this is considered. 

C. Free chlorine concentration must be non-detectable on a continuous basis (


CAUTION 

The RO unit must be secured to the floor to prevent walking or tipping. 

Four ½” diameter holes are located on the frame base for bolting the unit 

to the floor. 

2.4 POWER REQUIREMENTS 

The power requirements for the system are given on the nameplate / serial number label 

located on the front of the system. The system should be connected with a 

multiconductor, grounded cable to a disconnect switch box. The switch box should be 

located within approximately 10 feet of the system for the convenience of technicians 

servicing the unit. 

Ground the power cable to the ground connection in the motor starter housing box. 

Branch circuit conductors supplying the motor shall have an amperage capacity of not 

less than 125% of the motor full load current rating as defined by the National Electric 

Code. 

2.5 WATER REQUIREMENTS 

The inlet water supply must be adequate to provide the minimum flow requirement 

shown in the Product Description/Equipment Specifications in the Appendix. The inlet 

line should be sized to deliver this flow with a recommended pressure of 35 psig at the 

RO unit. A shutoff valve within 10 feet of the unit should be provided. A sample valve for 

checking feed water quality is located upstream of the prefilter, thus ensuring a true feed 

water sample. 

2.6 PRODUCT LINE 

At a minimum the field installed product line should be the same size as skid mounted 

product discharge from the RO system. In some cases it may be necessary to increase 

to the next pipe size to ensure against excessive pressure loss in the product to storage 

tank or point of use piping. A sample valve is located in the product line to facilitate 

sampling the quality of the product water. A flowmeter is supplied with the unit to 

continuously measure the product flow. The flowmeters supplied are fluid calibrated to 

obtain accurate flow measurements. Any replacement flowmeter should also be fluid 

calibrated. 

2.7 RESERVOIR (OPTIONAL) 

RO systems are designed to produce a constant supply of purified water. The 

membranes must be maintained in an operational or standby state to retain full 

effectiveness. Therefore, a reservoir is usually required, unless the system operates in 

direct-feed mode. The reservoir size is a function of space allocation in relation to 

system output. Therefore, size selection should be in accordance with this factor. 

USFilter can supply reservoirs of any desired capacity as an accessory to the basic RO 

system. 



2.8 ACCESSORY SENSORS (PRETREATMENT INTERLOCK AND TANK LEVEL(S) 

Provisions have been made for shutdown by accessory sensors, provided such sensors 

are equivalent to a single-pole, single-throw switch. When a shutdown condition exists, 

the RO system will resume normal operation automatically when the alarm condition has 

been corrected or no longer exists. Please refer to the steps that follow for installation 

instructions and locations (please refer to the RO Controller manual in the Appendix for 

further instruction). 

A. Open the controller enclosure door to expose the terminal connections. 

B. Dry contacts for the PRETREATMENT INTERLOCK should be connected 

between terminals 19 and 20 of the terminal strip. The HIGH TANK level switch 

input is connected between terminals 17 and 18. The MID TANK level switch 

input sensor is connected between terminals 15 and 16. 

NOTE: A normally closed switch or switches should be selected. The MC10 Controller 

may be used to connect one level switch to the controller (instructions are 

included with the MC10 manual located in the Appendix). 

C. To connect the accessory, remove the shorting wire where applicable and 

connect a single pole single throw normally closed sensor (TANK SWITCHES 

and PRETREATMENT INTERLOCK) between the respective terminals. It is 

recommended that shielded cable, properly grounded, be used to wire these 

sensors to avoid radio signal interference with these functions. 

2.9 SETTING THE FLUSH CYCLE TIME AND DURATION 

Refer to the MC10 RO Controller manual in the Appendix for detailed instructions. 

2.10 BEFORE POWER TURN ON 

CAUTION 

CAUTION 

CAUTION 

If an isolation valve is located downstream of the RO unit in the product, 

reject or autoflush piping, a pressure relief device must be installed to 

avoid an over pressurization condition that could irreversibly damage the 

RO unit and related components. 

Verify that all retaining “U” pins are in place on the RO pressure vessels 

before turning on the pump. 

Be sure the product water will not enter the user system during startup. 

The RO system must be operated for 24 hours to flush out the 

preservative solution before connecting to the user system. 

Once the feed water is plumbed to the system and the electrical power is connected, the 

electrician should verify correct motor rotation. 



2.11 INSTALLATION OF REVERSE OSMOSIS MEMBRANE(S) 

CAUTION 

CAUTION 

Never engage or disengage retaining “U” pins without wearing safety 

glasses. 

Never allow the RO membrane to dry out once it has been wet, or 

irreversible damage will result. 

USFilter Reverse Osmosis units are normally shipped with the membranes installed and 

preserved in sodium bisulfite solution. However, should the need arise, the following 

procedures may be followed to install membranes: 

A. Disconnect all tubing from all RO pressure vessel end caps. This is done by 

pushing in the outer ring of the quick disconnect fitting while at the same time 

pulling the tubing out of the fitting. 

B. Remove RO pressure vessels from the frame, taking care to identify their proper 

location(s). 

C. Remove all “U” pins and end caps from each RO pressure vessel. 

D. Remove the each RO membrane from the RO pressure vessel in the same 

direction in which the feed water flows through it. 

E. Before installing the new RO membrane, lightly lubricate the brine (chevron) seal 

and o-rings with glycerin or water. 

F. Load the RO membrane in the direction in which the feed water will flow, 

inserting the end without a brine (chevron) seal first. Be careful not to roll, cut or 

otherwise damage the brine (chevron) seals when loading each membrane. 

G. Replace the end cap into the RO pressure vessel end opposite from loading end. 

Secure the end cap with the retaining “U” pin. 

H. Install the end cap on the feed end and secure it with the other “U” pin. 

I. Re-install RO pressure vessels onto the frame in their proper location(s). 

J. Reconnect the tubing to all end cap tube fittings by pushing into the fitting until 

the tubing “locks” into place. 


RX Manual 04/04 Rev. 6 OPERATING INSTRUCTIONS 

3.1 CONTROLS AND INDICATORS 

3.0 OPERATING INSTRUCTIONS 

The controls and indicators used in the operation of the system are outlined in the MC10 

RO Controller manual located in the Appendix. The operator must be thoroughly familiar 

with the controls and their respective functions for proper operation and in order to 

maintain the quality of the product and eliminate unnecessary shutdowns. 

3.2 INITIAL STARTUP OF REVERSE OSMOSIS SYSTEM 

CAUTION 

CAUTION 

CAUTION 

Verify that all RO pressure vessel end cap retaining “U” pins are in place 

and secure. 

Do not run the motor for more than 30 seconds backwards or irreversible 

pump damage may result. 

The membrane feed pressure should not be allowed to exceed 250 psig at 

any time during operation. 

A. The operator should verify that appropriate pretreatment is in place and operating 

satisfactorily. Inappropriate or inoperative pretreatment can damage the 

membranes. 

B. Make all water, electrical, and drain connections according to installation 

instructions. 

C. Divert the outlet of the product water to a convenient drain. 

D. Turn on the feed water and the electrical power. With product water diverted to 

drain, fully open the reject throttling valve and close the reject recirculation 

throttling valve. 

E. Place the controller in the DIRECT FEED mode (refer to the Reverse Osmosis 

Controller manual in the Appendix for detailed instructions). Press the SYSTEM 

START button on the controller keypad to start the system, after a fifteen-second 

delay the pump should start. 

F. Check for proper pump rotation. (Please refer to the Pump Information, included 

in the Appendix of this manual for information concerning motor rotation and any 

other electrical requirements.) 

G. Set the reject recirculation flow to zero, but do not exceed 250 psig pressure to 

the membranes. Open the reject valve further if necessary to avoid over 

pressuring the system. 

CAUTION 

Do not use reject recirculation option for the first 4 hours of operation to 

speed flush up of the system. 



H. Set the percent rejection alarm setting to 90%. 

I. Check for plumbing leaks and make appropriate repairs as necessary. All 

systems are leak checked at the factory but vibration during transit can cause 

new leaks to develop. 

J. Once the system is checked out and operating correctly, place the controller in 

the desired mode. Read the next section on initial flushing before directing 

product water to the water storage tank or user system. 

3.3 INITIAL FLUSHING OF THE SYSTEM 

Since the RO membranes are shipped with sodium bisulfite preservative solution, initial 

flushing of the system is required. Before operating a new system, and also after the 

replacement of a RO membrane, perform the following steps: 

A. Direct the product water to a convenient drain. 

B. Ensure a steady feed water supply, turn on the system pump and let the system 

run for 24 hours. This will flush residual bisulfite solution and any particulate 

impurities from the membranes, housings and plumbing of the system. 

C. Product quality will increase slowly for 1 hour. Monitor the inlet quality vs. the 

product quality by observing the conductivity meter outputs. 

NOTE: The system should have better than 90% rejection within 2 hours as the 

membranes equilibrate. If the product quality does not improve, refer to 

section 5.0 Troubleshooting. 

D. After flushing product to drain for a minimum 24 hours, turn off the system and 

reconnect the product line. The system is now ready to be put into a normal 

operating mode. Refer to the Product Description/Equipment Specifications in 

the Appendix for design flowrates and pressures. 

3.4 NORMAL OPERATIONS 

The following procedure is for operating a USFilter Reverse Osmosis System that has 

been installed and initial flushing has been completed. Refer to the MC10 Controller 

manual in the Appendix for detailed instructions. 



Use this section for daily startup or to restart the system after a short-term shutdown. 

A. BEFORE starting the RO unit, verify that the following conditions exist: 

DEVICE CONDITION 

Pump discharge throttling valve ¼ to ½ OPEN 

Reject throttling valve ¼ to ½ OPEN 

Reject recirc throttling valve 1/8 to ¼ OPEN 

Any valves in the reject to drain line OPEN 

Any valves in the process supply line OPEN 

Pre treatment equipment ready for use 

Storage tank (if applicable) ready for use 

IF ALL THE ABOVE CONDITIONS EXIST, THE SYSTEM IS READY TO START. IF ONE OF 

THE SETTINGS IS INCORRECT, CORRECT THE SETTING PRIOR TO PROCEEDING. 

B. Verify the Controller is set to the proper operating mode, either TANK FEED or 

DIRECT FEED as described in the MC10 RO Controller manual in the Appendix. 

C. Press the SYSTEM START button on the Controller. This will start the system. 

The inlet solenoid valve will open then the pump will start after a 15 second 

delay. 

D. Verify that the product, reject, and product & reject recirculation flows are correct. 

If not, adjust the pump discharge throttling valve, reject valve, and product & 

reject recirculation valves. Refer to the Product Description/Equipment 

Specifications for design flowrates and pressures. Adjustment procedure: 

First, adjust the unit to make the correct amount of RO product water by 

adjusting the system pressure. This can be accomplished by regulating the 

pump discharge throttling valve. Further open the valve to increase the system 

operating pressure and productivity, further close the valve to reduce the system 

operating pressure and productivity. 

Second, adjust the unit to make the correct amount of reject to drain flow by 

adjusting the reject throttling valve. Open the valve to obtain a higher flow rate or 

close the valve to reduce the flow rate. 

Third, adjust the unit to make the correct amount of product and reject 

recirculation flows by adjusting the product and reject recirculation throttling 

valves. Further open the valve to obtain a higher flow rate or close the valve to 

reduce the flow rate. 

NOTE: Creating an equilibium may require several adjustments in that as you 

close the reject valves, the product flow increases and the reject flow 

decreases. As you open the pump discharge-throttling valve, the product 

and the reject flow increase. You may have to adjust the pump 

discharge-throttling valve to reestablish the operating pressure to obtain 

the correct product flow as established in the first step. 



E. Once the RO unit is operating at the parameters outlined in this manual, record 

the operating parameters on the “RO Data Collection Form” as described in 

Section 4.4, and found in the Appendix. It is imperative to record the operating 

parameters daily, since RO troubleshooting may require a trended analysis of the 

RO operating parameters. 

NOTE: If the RO will not start, or cannot achieve the correct flows, go to the 

troubleshooting section for more information. 

3.5 SHUTDOWN (LESS THAN 4 DAYS) 

CAUTION 

If the shutdown is due to a malfunction, be sure to disconnect the 

electrical power and turn off the water supply before making repairs or 

replacements. 

If the system is not to be operated for up to 4 days, the system should be placed in the 

STANDBY mode. When in this mode the RO system cycles on and off continuously for 

a duration and interval established by the user until the mode of operation is changed 

again. This mode will allow the system to return to normal (TANK or DIRECT FEED 

mode) operation at any time with no adverse affects on the water quality or RO 

membranes. 

3.6 LONG TERM SHUTDOWN PROCEDURE 

If the system is to be down for a period longer than 4 days, it is recommended that a 

biocide be pumped into the membrane elements to prevent biological growth. 

CAUTION 

Failure to store the membranes in a biocide for long term shutdown can 

cause irreversible damage to the membranes due to bacterial growth. 

NOTE: Contact your local USFilter representative to aid in preparing your RO system 

for long term shutdown and storage. 

The solution USFilter recommends is a 0.5 to 1.0% solution of sodium bisulfite. For 

conditions where freezing may be a problem, the solution should also contain up to 18% 

(by weight) glycerin or propylene glycol. Refer to RO membrane data sheet in Appendix 

for further information. 

The following equipment and materials are needed: 

CIP Cleaning Skid 

RO Product Water or DI Water 

Sodium Bisulfite (food grade) 

Propylene Glycol or Glycerin (if required) 

Safety Equipment 



CAUTION 

A. Fill the tank on the cleaning skid with the appropriate quantity of RO product 

water or DI water. 

Do not use a solution of greater than 1.0% bisulfite. The pressure vessel 

endcaps will be damaged otherwise. 

B. Add the correct amount of sodium bisulfite powder to the cleaning tank using the 

following proportions: 

0.5% solution sodium bisulfite - .042 lbs. per gallon 

1.0% solution sodium bisulfite - .084 lbs. per gallon 

If applicable, add the appropriate amount of freeze protection (glycerin or 

propylene glycol) to the solution at this point. 

C. Once the bisulfite solution is thoroughly mixed, allow the solution to circulate 

through the RO unit for 30 minutes. 

D. Fully close the manual feed water isolation valve and install a Lock-Out device 

and a Lock-Out Tag on the valve. 

E. If applicable, you may also have to fully close any process valves located in the 

RO unit product line down stream of the product line to prevent unwanted RO 

product water from passing this point, and install a Lock-Out device and a Lock- 

Out Tag on the valve. 

F. Drain the pump and manifold piping. 

G. Seal all openings to prevent the membrane elements from drying out. 

H. Tag the RO unit with the date and type of solution the membranes are stored in 

so that it is properly flushed prior to being put back into service. 

The RO unit is now ready to be stored. Be sure to follow the Initial Startup in 

Section 3.2 when ready to put the unit back in service. 


RX Manual 04/04 Rev. 6 SYSTEM MAINTENANCE 

4.1 GENERAL 

4.0 SYSTEM MAINTENANCE 

Routine customer maintenance procedures consist of daily checks of the system to 

record operating data, periodic replacement of the prefilter cartridge and sanitization and 

cleaning of the RO membranes. The prefilter cartridge should be changed monthly or 

when the differential pressure reaches 10-15 psig, whichever comes first. The RO 

membranes should be cleaned when the normalized product flow rate drops by more 

than 15% or the salt rejection drops by more than 3%. 

NOTE: Contact your local USFilter representative for assistance when the RO system 

requires cleaning. 

In addition, the system's external surface should be kept clean by occasionally wiping 

down all surfaces with a dust-free cloth and visually checking for cracked glass on 

gauges, loose fittings, and broken or missing hardware. 

Whenever the prefilter cartridge or RO membranes are replaced, inspect the 

serviceability of the o-ring seals prior to assembly. Inspect o-rings for signs of 

deterioration or cracking, and replace as required. It helps to lubricate o-rings with 

glycerin before re-assembly. 

4.2 SANITIZING THE REVERSE OSMOSIS SYSTEM 

WARNING 

WARNING 

CAUTION 

Verify that the system is not in use and Tag Out all points of use during the 

sanitization process. 

Verify sanitant has been flushed from the system by testing to nondetectable 

levels at the RO outlet and all points of use before returning the 

system to normal operation. 

Chlorine is not compatible with thin film composite RO membranes, and 

must not be used to sanitize them. 

Periodically, the RO System may require sanitization in order to maintain the 

performance of the RO membranes, and to ensure a low bacterial count in the product 

water. How frequently the system is sanitized depends on the quality of the water 

needed for your particular application. Monitor bacterial levels in the feed and permeate 

as needed. When bacterial levels increase above an acceptable level for the 

application, sanitize the system. Sanitization may be required as often as once a week 

or as infrequently as every three months depending on local feed water and operating 

conditions. Sanitization is recommended once a month to maintain peak operating 

conditions. 

The choice of the sanitizing agent depends on its compatibility with the polyamide thin 

film composite RO membranes and system components, and the agent’s effectiveness 

as a sanitant. The most commonly used sanitants are hydrogen peroxide and peracetic 

acid. Formaldehyde can also be used as a sanitant however it is rarely used due to 

stringent OSHA exposure limits. 



A. Different Sanitizing Agents 

1. Peracetic Acid (Preferred Method) 

Advantages of using peracetic acid are that it has no toxic vapors, is 

biodegradable, easily disposable, and has good biocidal activity. 

Peracetic acid decomposes into oxygen, water, and acetic acid. Several 

peracetic acid solutions are commercially available, including; Minncare 

and Renalin Dialyzer Reprocessing Concentrate, both products of 

Minntech Corporation, and P3-Oxonia Active, a product of Henkel 

Corporation. For ordering information call the number provided on the 

cover of this manual. 

2. Hydrogen Peroxide 

Advantages of using hydrogen peroxide are that it has low toxic vapors, is 

biodegradable, is easily disposable, has good biocidal activity, and breaks 

down into oxygen and water. 

B. Selecting a Sanitant 

Table 4-1 lists the type and concentration of sanitizing agent that should be used for polyamide 

thin film composite membranes, as well as the minimum contact time for sanitization. 

Table 4-1: Sanitization Times and Concentrations for Polyamide TFC Membranes. 

Sanitant Sanitant Concentration Sanitant Contact Time 

Peracetic Acid * up to 400 ppm (0.04%) 60-120 minutes 

Hydrogen Peroxide * up to 2,000 ppm (0.2%) 60-120 minutes 

* When using hydrogen peroxide or peracetic acid with thin film composite membranes, the 

temperature should not exceed 25° C (77° F). Also, the presence of iron or heavy metals 

can cause membrane degradation. Clean the membranes first if iron is present in the 

feed water. 



C. Testing for Residual Sanitant 

After flushing the sanitant from the RO system, the product water should be 

checked for residual levels of sanitizing agent before the system is placed back 

on line. Use the following guidelines to determine if the system is clear of 

residual sanitizing agents. 

1. Peracetic Acid 

The product water should be analyzed with the Peracetic Acid Residual 

Test Strip or other peracetic acid test kit. For ordering information call the 

number provided on the cover of this manual. 

2. Hydrogen Peroxide 

The product water should be analyzed with a hydrogen peroxide test kit. 

D. Methods of Sanitization 

Sanitization is most effective when the RO system is operating at normal 

pressure and flows. This allows the maximum amount of sanitant to penetrate 

through the membrane, ensuring adequate sanitization of the product side of the 

system. In addition, sanitant should contact all wetted components of the RO 

system including prefilter housing, valves, flowmeters, and sample ports to 

ensure maximum effectiveness. 

Recirculation Method 

This method requires an accessory tank and booster pump clean in place 

(CIP) system US Filter model number MEDROCIP or equivalent system. 

A sanitant solution is prepared in the tank and fed to the RO system via 

the booster pump. The product and reject streams are diverted to the 

tank and the sanitant is recirculated through the system for a period of 

time. 

The advantages of the recirculation method of sanitization are minimal 

usage of chemical, and ease in obtaining the proper sanitant 

concentration. In addition, the accessory tank and booster pump may 

also be used for system cleaning. 

The following steps provide a general guideline for the recirculation 

method of sanitization. 

a. The RO system is put into sanitization lockout mode. During 

sanitization lockout the RO system will not run. 

b. A batch of sanitant, typically 15 to 50 gallons (60 to 200 liters) for 

the RX series RO systems is prepared in the CIP tank by diluting 

the sanitization chemical with pretreated RO feedwater or RO 

product water, following the sanitant chemical manufacturer’s 

recommendation. 

c. Connect the cleaning CIP skid to the RO system. The product 

and reject lines are diverted back to the CIP tank. Use the RO 



pump discharge, reject, and product cleaning ports on the RO 

system to make these connections. 

d. The cleaning skid pump is turned on and run for 30 to 60 minutes. 

Adjust the reject flow. Verify the reject, reject recycle, and product 

flows and ensure sanitant reaches these areas of the system. 

CAUTION Monitor the solution temperature during recirculation. Do not 

allow the temperature to exceed 25° C (77° F). 

e. The cleaning pump can be shut down and the sanitant can soak 

for a maximum contact time of 2 hours, including recirculation 

time. 

f. Divert the product and reject lines to drain. Flush the sanitant 

from the system, filling the CIP with pretreated RO feedwater. 

Continue flushing for 15-30 minutes to remove the residual 

sanitant. When flushing the chemical from the system, close the 

reject recirculation valve. This will rinse chemical out more 

efficiently since it is not recycled back to the front end of the 

system. 

g. The RO is switched back to the normal feed source and run in the 

normal operating mode with the product diverted to drain until all 

residual sanitization chemicals are flushed from the system. 

h. The CIP tank and booster pump are drained and flushed with 

clean water. 

i. A new prefilter is installed in the system prefilter housing. 

NOTE: The introduction of sanitant by filling the prefilter housing has not been tested 

and proven to be an effective method of sanitizing the RO system. 



4.3 CLEANING THE RO MEMBRANES 

WARNING 

WARNING 

Verify that the system is not in use and Tag Out all points of use during the 

cleaning process. 

Verify cleaning solutions have been flushed from the system by testing to 

non-detectable levels at the RO outlet and all points of use before returning 

the system to normal operation. 

A. General Information 

This section includes general guidelines for developing a cleaning procedure for 

your particular application. When RO systems have adequate pretreatment and 

are properly operated, they do not require frequent cleaning. In time, however, 

the RO membranes can become fouled to a point where system performance is 

adversely affected, resulting in diminished product output or salt rejection. When 

the normalized product flow rate drops by 15% and/or the salt passage rises 

noticeably, this may indicate fouling of the RO membranes and a need for 

cleaning. However, other factors such as temperature decreases, or 

malfunctioning pretreatment systems, pressure controls and pumps may also 

cause these conditions. It is important to rule out these factors before cleaning 

the system. 

Clean the membranes if the system performance (based on flow rate or salt 

rejection) decreases because of membrane fouling. A 15% increase in the feed 

to reject differential pressure also indicates that cleaning is needed. 

Membrane foulants include colloidal materials such as aluminum and silica 

compounds precipitated metal hydroxides of iron and manganese, biological 

films, and calcium or magnesium carbonate scale. The type of cleaning solution 

(See Table 4-2) depends on the type of foulant present (organic compounds, 

metal hydroxides, Ca/Mg carbonates, etc.). The need for frequent cleaning 

(once a month or more), may indicate that pretreatment is inadequate. 

B. Factors to Consider when Cleaning RO Membranes 

1. Cleaning skid required. 

An accessory cleaning skid consisting of a tank and recirculation pump is 

required to effectively clean the system. The tank and pump should be of 

materials compatible with the cleaning chemicals. Plastic tanks and sealless 

(magnetic drive) plastic pumps are recommended. A tank capacity 

of 15-30 gallons is sufficient for the Med-RO series RO systems. 

2. Use RO product water for cleaning and rinse solutions. 

Use RO product water to prepare cleaning solutions, and as flush water 

between each cleaning step. If RO product water is not available, use 



softened filtered tap water. Completely flush the system between 

applications of different cleaning solutions. 

3. Increase flow rates and decrease pressure. 

During cleaning, reject flow rates should be as high as possible without 

exceeding the maximum design flow of the system. The flow rate should 

be 8 - 12 gpm per vessel for the Med-RO series RO systems during 

cleaning. Pressure should be kept at a minimum during cleaning. 

Transmembrane pressure keeps foulants within or on the membrane 

surface during cleaning. The RO pump should be off during cleaning. 

4. Optimum temperature during cleaning: 

The RO membrane cleaning solutions should be maintained at an 

elevated temperature if possible. Cold water reduces the effectiveness of 

the cleaning solution. Do not exceed the following temperatures during 

cleaning: 

C. Cleaning Instructions 

pH Range Maximum Cleaning Temperature 

2-10 50°C (122°F) 

1-11 35°C (95°F) 

1-12 30°C (86°F) 

1. Connect the RO system cleaning port (CP) connections to the accessory 

cleaning skid. Flexible hose and tubing work best to connect the 

cleaning equipment with the system. The materials of construction of the 

valves and hose must be compatible with the cleaning solutions. Verify 

that all piping connections are secure. 

2. Mix the desired cleaning solution in the tank and warm to appropriate 

cleaning temperature. 

3. Pump the mixed cleaning solution into the RO system at low pressure at 

the recommended flow rate of per vessel. The pressure should be low 

enough that essentially no permeate is produced. 

4. Recirculate the cleaning solution through the RO system for 10 – 15 

minutes. 

5. Turn off the cleaning pump and allow the RO membranes to soak in the 

cleaning solution. The soak period may range from 1 hour to overnight, 

depending on how severely fouled the membranes are. Turn on the 

cleaning pump periodically to circulate the cleaning solution. If the 

cleaning solution becomes highly discolored during recirculation, discard 

it and repeat the application. 



6. Recirculate the cleaning solution at 8-12 gpm per vessel for 30-60 

minutes. This high flow rate flushes out foulants removed from the RO 

membranes. 

CAUTION If the system temperature approaches the maximum recommended 

operation temperature during recirculation, shut down the system 

and allow it to cool off before continuing the recirculation. 

7. Disconnect the RO system from the cleaning skid. Divert the product and 

reject lines to drain. 

8. Flush the cleaning solution from the system, starting with a 10 to 15 

minute manual flush cycle. Then place the system in the normal 

operating mode, and for the first ten minutes, reduce the feed pressure to 

approximately half of the normal operating pressure by opening the reject 

and reject recycle throttle valves. This prevents residual foulants from 

being impacted into the membrane. After ten minutes, return the system 

to normal operating pressure, and continue flushing until the product 

water is clear of all residual cleaning agents. To test for residual cleaning 

agents when using an acid or base, the pH of the product water would be 

equal to, or nearly equal to, the pH of the feed water. For other 

chemicals, the conductivity of the product should be equal to, or less 

than, the conductivity of the product before cleaning. 



Table 4-2: Cleaning Solutions for Polyamide Thin Film Composite Membranes. 

0.1% (W) 1 

NaOH and pH12, 30°C 

max. 

or 1.0% (W) Na4EDTA 

and pH12, 30°C max. 

0.1% (W) 1 

NaOH and pH12, 30°C 

max. 

or 0.025% (W) NaDSS 

and pH12, 30°C max. 

0.1% STP 

and 1.0% (W) 1 Na4EDTA 

or 1.0% TSP and 

pH12, 30°C max. 

Inorganic 

Salts 2 

Metal 

Oxides 

(Iron) 

0.2% (W) 1 HCl BEST 

0.5% (W) 1 H3PO4 OK GOOD 

2.0% (W) 1 Citric Acid OK 

1.0% (W) 1 Na2S2O4 

GOOD 

NOTES: 

1. (W) Denotes weight percent of active ingredient. 

Inorganic 

Colloids 

(Silt) 

Silica Biofilms Organics 

OK BEST OK 

GOOD GOOD GOOD 

GOOD GOOD 

2. Inorganic Salts: CaCO3=Calcium Carbonate; CaSO4=Calcium Sulfate; BaSO4=Barium 

Sulfate. 

3. Cleaning chemical symbols: NaOH=Sodium Hydroxide; Na4EDTA is the Tetrasodium Salt of 

Ethyl Diamine Tetraacetic acid; NaDSS is Sodium Salt of Dodecylsulfate; STP is Sodium 

Triphosphate (Na5P3O10); TSP is Trisodium Phosphate (Na3PO4·12H2O); HCl is Hydrochloric 

Acid; H3PO4 is Phosphoric Acid; C3H4(OH)(CO2H)3 is Citric Acid; Na2S2O4 is Sodium 

Hydrosulfite. 



4.4 MAINTENANCE SCHEDULE 

NOTE: The maintenance schedule for monitoring outlined is a minimum for the 

protection of the RO system. A more frequent monitoring schedule may be 

necessary. Consult your local USFilter representative or call USFilter, 

Technical Support Department at the number provided on the cover of this 

manual for assistance. 

Refer to the RO Data Collection Form in the Appendix. 

A. Feed water 

1. Check pressure daily; record weekly. Adjust as necessary to maintain 35 

to 80 psi. 

2. Monitor feed and product conductivity and record weekly. 

3. If there is a possibility of the presence of chlorine in the feed water, 

measure free chlorine weekly. (It must be non-detectable or the 

membranes may be damaged). 

4. If there is a possibility of significant pH variations (i.e. the feed is pH 

controlled) monitor and record pH weekly by independent pH meter or 

litmus paper. 

5. Measure total hardness monthly. 

6. Measure total alkalinity monthly. 

B. Prefilter 

1. Measure differential pressure daily; record weekly. 

2. Change prefilter cartridge when the differential pressure is greater than 

10 psi or every month, whichever occurs sooner. 

C. Pump 

1. Check pressures daily; record weekly. 

2. If the pressures have fallen off, check product, reject and reject 

recirculation flow rates. 

D. Conductivity 

1. Observe feed and product conductivity daily; and record weekly. 

2. Record percent salt rejection weekly. 

Conductivity Feed - Conductivity Product 

100 X = % Rejection 

Conductivity Feed 

E. Flow Rates 

1. Check daily and record product and reject flow rate weekly. 

2. Calculate the percent recovery using the following formula: 



Product Flow Rate 

100 X = % Recovery 

Product Flow Rate + Reject Flow Rate 

The percent recovery should not exceed the design value shown on the 

Equipment Specifications sheet in the Appendix. If minimizing water usage is 

critical, the percent recovery should be maintained near, but not above the 

maximum value. Operating with too high a percent recovery will lead to 

premature fouling of the membrane. 

F. Bacteria 

1. For critical applications, such as dialysis and pharmaceuticals, measure 

the number of bacteria in the product water weekly. Record the results as 

colony forming units per milliliter (CFU/ml). Sanitize as necessary. 

2. For non-critical applications, measure the number of bacteria in the 

product water monthly. Record the results as colony forming units per 

milliliter (CFU/ml). Sanitize as necessary. 

G. If the maintenance log shows steady deterioration in results (product flow, 

percent rejection, etc.) corrective action should be taken. (Described in Section 

5.0 Troubleshooting.) 


RX Manual 04/04 Rev. 6 TROUBLESHOOTING 

5.1 SYSTEM INOPERATIVE 

5.0 TROUBLESHOOTING 

A. Check to see if power to the unit is turned on. 

B. Verify the controller indicates that the system is on, if not press the system start 

button. 

C. Verify that the motor starter relay is engaging, if not reset the overload relay. If 

the overload relay fails to reset, replace the overload relay or contact your 

USFilter representative for further assistance. 

D. Check the motor starter coil for proper operation and replace if necessary. 

E. With a voltmeter check that power is being supplied to the motor. If proper 

voltage is going to the motor but it does not run, replace the motor or contact 

your USFilter representative for further assistance. 

5.2 LOW SYSTEM PRESSURE 

A. If the feed pressure before the prefilter is too low, check for obstruction in 

equipment and piping between feed source and RO unit. 

B. If the feed pressure after the prefilter is below normal, check for high differential 

pressure across the prefilter (plugging), replace the filter cartridge. 

C. If the membrane feed pressure is below normal, verify that the pump is running. 

D. Verify that the reject, reject recycle and product flows are normal. If not, adjust to 

design flow rates using the Equipment Specifications located in the Appendix and 

recheck membrane feed pressure. 

E. If the flows cannot be adjusted to the above flow rates, slowly close the reject 

and reject recirculation valves to observe the maximum pressure to the 

membrane. Do this only briefly and do not completely close the valve. If this 

pressure does not exceed 150 psig, repair or replace the pump/motor. 

5.3 LOW PERCENT RECOVERY 

A. Check product, reject, reject recycle flow rates and feed pressures to be sure 

they are normal; adjust flows as necessary. 

B. If feed to membrane pressure exceeds normal by 10% and product flow is lower 

than normal at a given temperature, the RO membranes are beginning to fail. 

They should be cleaned or replaced. 





5.4 HIGH PERCENT RECOVERY 

A. Verify that the reject, reject recycle and product flows are normal. If not, adjust to 

design flow rates using the Equipment Specifications located in the Appendix. 

B. Set the membrane pressure to 200 psig. 

C. If the product flow is high after adjusting the pressures and flows, the RO 

membrane o-rings may be leaking. Check percent rejection. 

5.5 LOW SALT REJECTION 

A. Verify that the feed water temperature has not increased substantially from 

normal. High temperatures can affect percent rejection, as temperature 

increases, percent rejection decreases. 

B. Check product, reject, reject recycle flow rates and feed pressures per the 

Equipment Specifications in the Appendix, and adjust flows/pressures as 

necessary. 

C. Another possibility is high CO2 content in the inlet water. CO2 readily permeates 

the membrane. High CO2 content water will also have a pH of less than 6.0. 

D. RO membrane o-rings may not be seated correctly, check the percent rejection 

for each individual membrane housing. Remove membranes and verify o-rings 

are seated correctly on any that are below 90% rejection. 

E. If the above possibilities are eliminated, RO membranes are beginning to fail. 

They should be cleaned or replaced. 



5.6 SYSTEM KEEPS SHUTTING OFF 

A. Observe the controller indicators to see if they indicate the cause for system 

shutdown, if the controller is shutting the unit down refer to the RO controller 

section of this manual for further discussion. 

B. The motor is equipped with automatic thermal overload protection. If the motor 

gets too hot it will shut down. After it has cooled it will restart. Excessive amp 

draw can cause the motor to get too hot. 

C. If an optional sensor is being used (Tank Level switch(es), Pretreatment 

Interlock), check to verify the sensor is not shutting off the system. 

5.7 SYSTEM SHUTOFF, LOW PRESSURE 

A. Verify that the feed water pressure is above 15 psig. 

B. Check the differential pressure across prefilter(s). It should be less than 10 psig, 

if not replace the prefilter cartridge filter and recheck feed pressure. 



C. Check the pump suction pressure. It should be greater than 15 psig, if not check 

for obstruction in piping between the prefilter and pump suction. 

D. Verify the low pressure switch is operating properly. 

5.8 SYSTEM SHUTOFF, HIGH TEMPERATURE 

A. Check incoming water temperature. 

B. The high temperature shut down is user settable and should activate around the 

35°C ± 3°C (95°F ± 5°F). 

C. The temperature thermistor (sensor) is combined in the feed conductivity probe 

circuitry. The probe may be replaced if it is giving an erroneous temperature 

indication. (Refer to the RO Controller manual in the Appendix for correct 

values.) 

5.9 LOW PRODUCT FLOW RATE 

A. Low feed water temperature can substantially reduce the performance of the RO 

unit. 

B. Adjust the reject throttling valve to increase membrane feed pressure, this 

adjustment should increase the product flow rate. Do not exceed 250 psig. 

C. If adjusting the reject throttling valve does not improve product flow rate, the RO 

membranes are fouled and should be cleaned with an appropriate medium. 

Depending on the type of fouling suspected, various regeneration/cleaning 

solutions may be used. 



5.10 MOTOR OVERLOAD SHUTDOWN 

A. Motor overload shutdown is caused by excessive amp draw. An overload relay 

is wired directly to the motor starter and it will shut the system down if it runs 

above the full load amp rating of the motor. Reset the overload relay by pressing 

the “RESET” button on the starter enclosure. If the unit continues to trip the 

overload relay and shutdown contact your local USFilter representative or 

USFilter Technical Support Department at the number provided on the cover of 

this manual. 

B. If the overload is shutting the unit down due to damage or binding within the 

pump/motor, repair or replace the pump/motor or contact your local USFilter 

representative or USFilter Technical Support Department at the number provided 

on the cover of this manual. 

5.11 CONTROLLER MALFUNCTION 

Refer to the RO Controller manual in the Appendix for troubleshooting controller related 

malfunctions. 




RX Manual 04/04 Rev. 6 WARRANTY 

6.1 GENERAL LIMITED WARRANTY 

6.0 WARRANTY 

USFilter warrants the products manufactured by it against defects in materials and 

workmanship when used in accordance with the applicable instructions for a period of one 

year from the date of shipment of the products. USFilter MAKES NO OTHER WARRANTY, 

EXPRESSED OR IMPLIED. THERE IS NO WARRANTY OF MERCHANTABILITY OR 

FITNESS FOR A PARTICULAR PURPOSE. The warranty provided herein and the data, 

specifications and descriptions of USFilter products appearing in USFilter’s published 

catalogs and product literature may not be altered except by express written agreement 

signed by an officer of USFilter. Representations, oral or written, which are inconsistent 

with this warranty or such publications are not authorized and if given, should not be relied 

upon. 

In the event of a breach of the foregoing warranty, USFilter’s sole obligation shall be to 

repair or replace, at its option, any product or part thereof that proves defective in materials 

or workmanship within the warranty period, provided the customer notifies USFilter promptly 

of any such defect. The exclusive remedy provided herein shall not be deemed to have 

failed of its essential purpose so long as USFilter is willing and able to repair or replace any 

nonconforming USFilter product or part. USFilter shall not be liable for consequential 

damages resulting from economic loss or property damages sustained by a customer from 

the use of its products. 

6.2 WATER SYSTEM LIMITED WARRANTY 

USFilter warrants the water systems manufactured by it, BUT EXCLUDING MEMBRANES 

AND CARTRIDGES, against defects in materials and workmanship when used in 

accordance with the applicable instructions and within the operating conditions specified for 

the systems for a period of one year from the earlier of: (i) the date of installation; or (ii) 120 

days following the date of shipment. USFilter MAKES NO OTHER WARRANTY, 

EXPRESSED OR IMPLIED. THERE IS NO WARRANTY OF MERCHANTABILITY OR 

FITNESS FOR A PARTICULAR PURPOSE. The warranty provided herein and the data, 

specifications and descriptions of USFilter systems appearing in USFilter’s published 

catalogs and product literature may not be altered except by express written agreement 

signed by an officer of USFilter. Representations, oral or written, which are inconsistent 

with this warranty or such publications are not authorized and if given, should not be relied 

upon. 

In the event of a breach of the foregoing warranty, USFilter’s sole obligation shall be to 

repair or replace, at its option, any product or part thereof that proves defective in materials 

or workmanship within the warranty period, provided the customer notifies USFilter promptly 

of any such defect. The exclusive remedy provided herein shall not be deemed to have 

failed of its essential purpose so long as USFilter is willing and able to repair or replace any 

nonconforming USFilter system or component part thereof. USFilter shall not be liable for 

consequential damages resulting from economic loss or property damages sustained by 

any customer from the use of its process systems. 


RX Manual 04/04 Rev. 6 WARRANTY 

Products or components manufactured by companies other than USFilter or its affiliates 

(“Non-USFilter Products”) are covered by the Warranty, if any, extended by the Product 

manufacturer. USFilter hereby assigns to the purchaser any such warranty: however, USF 

EXPRESSLY DISCLAIMS ANY WARRANTY, WHETHER EXPRESSED OR IMPLIED 

THAT THE NON-USF PRODUCTS ARE MERCHANTABLE OR FIT FOR A PARTICULAR 

PURPOSE. 


RX Manual 04/04 Rev. 6 APPENDIX 

7.1 GLOSSARY OF TERMS 

7.0 APPENDIX 

The terms commonly used in reverse osmosis are defined below: 

ANION - Negatively charged ion, such as CO3 -- , SO4 -- , HCO3 -- , Cl - , NO3 - , etc. 

CATION - Positively charged ion, such as Ca ++ , Mg ++ , Fe ++ , Na + , K + , etc. 

CONCENTRATE (REJECT) - Concentrated portion of the feed remaining outside the 

membrane which is discarded. 

CONDUCTIVITY - A measure of salt concentration due to the ability of dissolved solids (ions) to 

conduct electricity, usually expressed as micromhos/cm. 

FEED - The feedwater pumped into a permeator under high-pressure. 

OSMOSIS - Osmosis is the diffusion of a solvent (such as pure water) from a dilute saline 

solution into a more concentrated saline solution through a semipermeable membrane 

separating the two solutions. 

OSMOTIC HEAD - Osmotic head (pressure) is the change in head resulting from water 

transport through the semipermeable membrane separating two saline solutions of different 

concentrations. 

PASSAGE - Ratio of permeate to feed concentration of a particular dissolved material, 

expressed in percent. 

PERMEATE (PRODUCT) - The purified portion of the feed passing through the membrane. 

RECOVERY - Percent of feedwater converted into permeate. 

REVERSE OSMOSIS (RO) - The process by which incoming fluid (feed) is forced under highpressure 

through a reverse osmosis membrane. A portion of the fluid with concentrated ionic 

materials (concentrate) remains upstream of the membrane and is discarded (unless it is of 

interest in a particular application). The highly purified portion (permeate) which passed through 

the membrane would then be collected for use (as in a water purification application). 

REVERSE OSMOSIS (RO) MEMBRANE - An RO membrane is a semipermeable membrane 

generally in sheet or hollow fiber form which rejects not only dissolved materials, but also 

organics, submicron size colloidal materials and bacteria which may contaminate a high purity 

water system. The process is not absolute and therefore most reverse osmosis membranes are 

defined by their rejection characteristics. 

SOLUTE - Material (salts) dissolved by solvent (water). 

TOTAL DISSOLVED SOLIDS - Total dissolved inorganic salts present in the permeator stream 



7.2 REPLACEMENT/SPARE PARTS LIST – RX MODEL 

PART NUMBER DESCRIPTION 

D1004490 FOR UNITS W/ 1-6 VESSELS: CARTRIDGE DUAL GRADIENT FILTER 5 

MICRON 10” BIG BLUE 

D1000237 FOR UNITS W/ 1-6 VESSELS: CARTRIDGE FILTER HOUSING, 10” BIG 

BLUE 

D1004512 FOR UNITS W/ 8, 9, OR 12 VESSELS: CARTRIDGE DUAL GRADIENT 

FILTER 5 MICRON 20” BIG BLUE 

D1000245 FOR UNITS W/ 9, 9, OR 12 VESSELS: CARTRIDGE FILTER HOUSING, 20” 

BIG BLUE 

B10012424 CARTRIDGE FILTER BOWL 

B10012167 CARTRIDGE FILTER O-RING 

15/03995-02 PRESSURE GAUGE 0-100 PSI SS BTM MT 

15/03995-04 PRESSURE GAUGE 0-600 PSI SS PNL MT 

15/03995-03 PRESSURE GAUGE 0-300 PSI SS PNL MT 

15/03995-06 PRESSURE GAUGE 0-300 PSI SS BTM MT 

CDRC4X40L RO MEMBRANE 

22/03994-01 LOW PRESSURE SWITCH 

22/16006-01 HIGH PRESSURE SWITCH 

05/02561-16 SOLENOID VALVE ADAPTER, 1” UNION (INLET STREAM) 

05/03993-16 SOLENOID VALVE 1 FPT 24V (INLET STREAM) 

05/03992-08 SOLENOID VALVE SS 1/2 FPT 24V (REJECT AUTOFLUSH) 

05/14353-12 PRODUCT RECIRC PRESS RELIEF VALVE 

06/31019-02 PRESSURE VESSEL, 1M 401A SS 300 PSI 

P92844 END PLUG (OSMOTIK PRT# 35401) 

P92845 U-PIN RETAINER (OSMOTIK PRT# 35402) 

P92846 O-RING, END PLUG SEAL (OSMOTIK PRT# 32029) 

P92847 O-RING, TUBE SEAL (OSMOTIK PRT# 32030) 

05/01473-12 CHECK VALVE, 3/4 FPT, PVC 

05/02910-08 GLOBE VALVE, 1/2 FPT, SS 

05/02910-16 GLOBE VALVE, 1 FPT, SS 

P91141 SAMPLE VALVE 

21/06129-02 FLOWMETER 1-17 GPM 

21/03995-03 FLOWMETER 1-10 GPM 

18/03951-01 CONDUCTIVITY SENSOR 3/4 MPT 

03/03672-08 0.5 AMP FUSE FOR 460/575V MODELS ONLY 

03/03672-10 0.8 AMP FUSE FOR 380V MODELS ONLY 

03/03672-11 1 AMP FUSE 

04/30741-05 PUMP, 3 HP 230/460 TEFC GRUNDFOS CRI3-19 

04/30741-06 PUMP, 3 HP 575V TEFC GRUNDFOS CRI3-19 

04/30741-07 PUMP, 3 HP 380V TEFC GRUNDFOS CRI3-29 



04/31972-06 PUMP, 7.5 HP 230/460V TEFC GRUNDFOS CRI5-20 

04/31972-07 PUMP, 7.5 HP 230/460V TEFC GRUNDFOS CRI5-24 

04/31972-08 PUMP, 7.5 HP 575V TEFC GRUNDFOS CRI5-20 

04/31972-09 PUMP, 7.5 HP 575V TEFC GRUNDFOS CRI5-24 

04/31972-11 PUMP, 7.5 HP 380V 50HZ TEFC GRUNDFOS CRI5-32 

04/31972-12 PUMP, 7.5 HP 380V 50HZ TEFC GRUNDFOS CRI5-36 

03/30557-01 STARTER 9A 24V 50/60HZ NON-RVS OPN 1N 




03/30565-04 OVERLOAD RELAY, 3.7-12A SS (C09-C23) 

03/30565-05 OVERLOAD RELAY, 12-32A SS (C09-C23) 

03/30565-06 OVERLOAD RELAY, 12-37A SS (C30-C37) 

03/30551-03 TRANSFORMER FOR 575V MODELS 



10/64045-08 NYLON TUBING 1/2 OD 

10/30006-01 PP TUBING 5/8 OD 

12/03998-18 ¾” HOSE, SS W/SS FITTINGS, 18” LONG 



12/15037-36 1” HOSE, SS W/SS FITTINGS, 36” LONG 

26/10715-01 LEVELING PAD 

03/03929-01 MC10 CONTROLLER 



7.3 RO DATA COLLECTION FORM 

SYSTEM IDENTIFICATION: ______________________________________ 

WEEK ENDING DATE: __________________________________________ 

See calculated values on next page. 

RO UNIT OPERATING PARAMETERS* 

RO Cartridge Filter Outlet Pressure (PSI) 

RO Cartridge Filter Inlet Pressure (PSI) 

RO Cartridge Filter Pressure Drop (PSI) 

S M T W T F S 

1 

Product Flow Rate (GPM) 

Reject Flow Rate (GPM) 

Feed Flow Rate (GPM) 2 

Reject Recirculation Flow Rate (GPM) 

Product Recovery (%) 3 

Feed Water Temperature ( o F) 

Feed Water pH (0-14) 

Feed Water Chlorine Concentration (PPM) 

Feed Water Total Hardness (PPM as CaCO3) 

Feed Water SiO2 (PPM as SiO2) 

Feed Water Conductivity (µS/cm) 

RO Product Conductivity (µS/cm) 

RO Final Reject Conductivity (µS/cm) 

RO Percent Rejection (%) 4 

RO Pump Discharge Pressure (PSI) 

RO Membrane Feed Pressure (PSI) 

RO Product Pressure (PSI) 

RO Final Reject Operating Pressure (PSI) 

RO Normalized Productivity (GPM) 5 

* If Applicable 

COMMENTS: 

DATA TAKEN BY: 



Calculated Values: 

1: RO FILTER PRESSURE DROP is equal to filter inlet pressure MINUS filter outlet 

pressure. 

2: RO FEED FLOW rate is equal to RO product flow PLUS the RO reject flow. 

3: RO PRODUCT RECOVERY is equal to the RO product flow rate DIVIDED by the RO 

feed flow rate, MULTIPLIED by 100. 

EXAMPLE: Product flow = 3 GPM 

Feed flow = 4 GPM 

(3 ÷ 4) x 100 = 75% recovery 

4: RO PERCENT REJECTION* is equal to the RO feed conductivity MINUS the RO 

product conductivity, DIVIDED by the feed conductivity, TIMES 100. 

EXAMPLE: Feed conductivity = 380 µS/cm 

Product conductivity = 5 µS/cm 

{(380-5) ÷ 380} x 100 = 98.6% rejection 

* The RO Quality monitor is set up at the factory to display this value. 

5: NORMALIZED PRODUCTIVITY is a true indication of membrane performance. It is 

calculated as follows: 

NPF = MPF X TCF X (125÷MFP) 

Where: 

NPF = NORMALIZED PRODUCT FLOW 

MPF = MEASURED PRODUCT FLOW 

TCF = TEMPERATURE CORRECTION FACTOR (See table next page) 

MFP = MEASURED MEMBRANE FEED PRESSURE 

EXAMPLE: MPF = 3.5 GPM 

FEED WATER TEMP = 60 o F, THEN TCF = 1.44 

MFP = 150 PSIG 

NPF = 3.5 x 1.44 x (125÷150) 

NPF = 3.5 x 1.44 x 0.833 

NPF = 4.2 GPM 



RO FEED WATER TEMPERATURE CORRECTION FACTOR 

TEMP o F TCF TEMP o F TCF 

34 3.64 70 1.12 

36 3.18 72 1.08 

38 2.93 74 1.05 

40 2.68 76 1.02 

42 2.47 78 0.97 

44 2.29 80 0.93 

46 2.14 82 0.90 

48 2.01 84 0.88 

50 1.88 86 0.86 

52 1.77 88 0.82 

54 1.68 90 0.79 

56 1.59 92 0.77 

58 1.51 94 0.75 

60 1.44 96 0.73 

62 1.36 98 0.70 

64 1.30 100 0.68 

66 1.24 102 0.65 

68 1.17 104 0.63 



7.4 QA DATA REPORT 

See QA Data Report that follows this page. 



7.5 DRAWINGS 

Only the drawings checked below that apply to your system will be included in this section. 

Dwg/Doc # Model Description 

RX501-RX All Models Product Description/Equipment Specifications – RX Model 

RX501-001 MRORX01XX P&ID, 1 Vessel – RX Model 









RX501-210 MRORX01XX General Arrangement Drawing, 1 Vessel – RX Model 





RX501-255 MRORX05DX General Arrangement Drawing, 5 Vessel – RX Model (50 Hz) 


RX501-265 MRORX06DX General Arrangement Drawing, 6 Vessel – RX Model (50 Hz) 




SV301-051 MRORXXXAX Electrical Schematic, 208V/3Ph/60Hz, RX Model 

SV301-052 MRORXXXBX Electrical Schematic, 230V/3Ph/60Hz, RX Model 

SV301-053 MRORXXXCX Electrical Schematic, 460V/3Ph/60Hz, RX Model 

SV301-054 MRORXXXDX Electrical Schematic, 380V/3Ph/50Hz, RX Model 

SV301-055 MRORXXXEX Electrical Schematic, 575V/3Ph/60Hz, RX Model 



7.6 COMPONENT MANUFACTURER LITERATURE 

All literature listed below will be included in this section. 

Component Manufacturer Model Number Med-RO Model 

Pump, Vertical Centrifugal Grundfos CRI All Models 

Membrane Filmtec RO-4040-FF All Models 

Controller RODI Systems MC10 All Models 

Conductivity Sensor RODI Systems C273 All Models

USF RO ManualOMRX_6.pdf

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