Watts PWR4021 User Manual
Installation, Operation
and Maintenance Manual
Commercial Reverse Osmosis Systems
Series PWR4021
PURE WATER
!
CAUTION: Please read the entire manual before proceeding with the installation and startup. Your failure to follow any
attached instructions or operating parameters may lead to the
product’s failure, which can cause property damage and/or
personal injury.
• Do not use where the water is microbiologically unsafe.
• Pretreatment must be sufficient to eliminate chemicals that
would attack the membrane materials.
• Always turn off the unit, shut off the feed water, and discon-
nect the electrical power when working on the unit.
• Never allow the pump to run dry.
• Never start the pump with the reject valve closed.
• Never allow the unit to freeze or operate with a feed water
temperature above 100°F.
Save manual for future reference.
Please refer to Section 6 of this manual for operating parameters
according to your specific feed water Silt Density Index (SDI). For all
other settings according to your specific feed water quality, please
contact your Watts representative. A chemical analysis of the feed
water should be conducted prior to the initial sizing and selection of
this system.
Notes
Changes in operating variables are beyond the control of Watts. The
end user is responsible for the safe operation of this equipment.
The suitability of the product water for any specific application is the
responsibility of the end user.
Successful long-term performance of an RO system depends on
proper operation and maintenance of the system. This includes
the initial system startup and operational startups and shutdowns.
Prevention of fouling or scaling of the membranes is not only a matter of system design, but also a matter of proper operation. Record
keeping and data normalization are required in order to know the
actual system performance and to enable corrective measures when
necessary. Complete and accurate records are also required in case
of a system performance warranty claim.
Changes in the operating parameters of an RO system can be
caused by changes in the feed water or can be a sign of trouble.
Maintaining an operation and maintenance log is crucial in diagnosing and preventing system problems. For your reference, a typical log
sheet is included in this manual.
Table Of Contents
I. Introduction
A. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
B. RO Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
C. Pre-treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
II. Controls, Indicators, and Components
A. General System Component Identification – Figure #1 . . . . . . 3
B. Controller Drawing – Figure #2 . . . . . . . . . . . . . . . . . . . . . . . . 4
III. Operation
A. Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
B. Plumbing Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
C. Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
D. Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
E. Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
F. Operation and Maintenance Log . . . . . . . . . . . . . . . . . . . . . . 10
G. Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-13
IV. Replacement Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V. Membrane Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
VI. Appendix
Flow Rate Guidelines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Temperature Correction Factors . . . . . . . . . . . . . . . . . . . . . . . . 14
Electrical Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
IOM-WQ-PWR4021
Series PWR4021
Note: Do not use with water that is microbiologically unsafe or
of unknown quality without adequate disinfection before or after
the system.
I. Introduction
The separation of dissolved solids and water using RO membranes
is a pressure driven temperature dependent process. The membrane
material is designed to be as permeable to water as possible while
maintaining the ability to reject dissolved solids.
The main system design parameters require the following:
• Internal flows across the membrane surface must be high enough
to prevent settling of fine suspended solids on the membrane
surface.
• The concentration of each dissolved ionic species must not exceed
the limits of solubility anywhere in the system.
• Pre-treatment must be sufficient to eliminate chemicals that would
attack the membrane materials.
A. Specifications
PWR40213023 PWR40213033 PWR40213043 PWR40213053 PWR40213063
Productivity (gallons per day / gallons per minute) Maximum production based on standard
membranes and feed water of 25°C, SDI < 3, 1000 ppm TDS, and pH 8. Individual membrane
productivity may vary (± 15%).
Quality (typical membrane percent rejection) Based on membrane manufactures
specifications, overall system percent rejection may be less.
Recovery without reject recycle 29 % 39 % 50 % 57 % 62 %
Recovery with reject recycle (adjustable) 50 % 50 % 75 % 75 % 75 %
Membrane Size 4 x 40 4 x 40 4 x 40 4 x 40 4 x 40
Number Of Membranes Per Vessel 1 1 1 1 1
Pressure Vessel Array 1:1 1:1:1 1:1:1:1 1:1:1:1:1 1:1:1:1:1:1
Number Of Membranes 2 3 4 5 6
Prefilter (system ships with one 5 micron cartridge) 20" BB 20" BB 20" BB 20" BB 20" BB
Feed Water Connection 1" NPT 1" NPT 1" NPT 1" NPT 1" NPT
Product Water Connection
Reject Water Connection
Feed Water Required (feed water required will be less if reject recycle is used) 9 gpm 10 gpm 10 gpm 12 gpm 13 gpm
Feed Water Pressure (minimum) 20psi 20psi 20psi 20psi 20psi
Drain Required 9 gpm 10 gpm 10 gpm 12 gpm 12 gpm
Electrical Requirement 230 VAC, 3-ph, 60 Hz (other voltages available) 15 amps 15 amps 15 amps 15 amps 15 amps
TEFC Motor (horse power) 5 5 5 5 5
Dimensions L x W x H (inches) 60 x 18 x 56 60 x 18 x 56 60 x 18 x 56 60 x 18 x 56 60 x 18 x 56
Shipping Weight (estimated pounds) 400 500 600 700 800
3600 / 2.5 5400 / 3.75 7200 / 5.0 9000 / 6.25 10800 / 7.5
98 % 98 % 98 % 98 % 98 %
3
⁄4" NPT
3
⁄4" NPT
3
⁄4" NPT
3
⁄4" NPT
3
⁄4" NPT
3
⁄4" NPT
3
⁄4" NPT
3
⁄4" NPT
3
⁄4" NPT
3
⁄4" NPT
B. RO Overview
Reverse osmosis systems utilize semipermeable membrane elements to separate the feed water into two streams. The pressurized
feed water is separated into purified (product) water and concentrate
(reject) water. The impurities contained in the feed water are carried
to drain by the reject water. It is critical to maintain adequate reject
flow in order to prevent membrane scaling and/or fouling.
RO Membrane
Feed Water Product Water
Reject Water
2
C. Pretreatment
The RO feed water must be pretreated in order to prevent membrane damage and/or fouling. Proper pretreatment is essential for
reliable operation of any RO system.
Pretreatment requirements vary depending on the nature of the feed
water. Pretreatment equipment is sold separately. The most common
forms of pretreatment are described below.
Media Filter - Used to remove large suspended solids (sediment)
from the feed water. Backwashing the media removes the trapped
particles. Backwash can be initiated by time or differential pressure.
Water Softener - Used to remove calcium and magnesium from
the feed water in order to prevent hardness scaling. The potential
for hardness scaling is predicted by the Langelier Saturation Index
(LSI). The LSI should be zero or negative throughout the unit unless
approved anti-scalents are used. Softening is the preferred method
of controlling hardness scale.
Carbon Filter - Used to remove chlorine and organics from the
feed water. Free chlorine will cause rapid irreversible damage to the
membranes.
The residual free chlorine present in most municipal water supplies
will damage the thin film composite structure of the membranes
used in this unit. Carbon filtration or sodium bisulfite injection should
be used to completely remove the free chlorine residual.
Chemical Injection - Typically used to feed antiscalant, coagulant,
or bisulfite into the feed water or to adjust the feed water pH.
Prefilter Cartridge - Used to remove smaller suspended solids and
trap any particles that may be generated by the other pretreatment.
The cartridge(s) should be replaced when the pressure drop across
the housing increases 5 - 10 psig over the clean cartridge pressure
drop. The effect of suspended solids is measured by the silt density
index (SDI) test. An SDI of five (5) or less is specified by most membrane manufacturers and three (3) or less is recommended.
Iron & Manganese - Iron should be removed to less than 0.1 ppm.
Manganese should be removed to less than 0.05 ppm. Special media filters and/or chemical treatment is commonly used.
pH - The pH is often lowered to reduce the scaling potential.
Silica: Reported on the analysis as SiO2. Silica forms a coating on
membrane surfaces when the concentration exceeds its solubility.
Additionally, the solubility is highly pH and temperature dependent.
Silica fouling can be prevented with chemical injection and/or reducing the recovery.
II. Controls, Indicators, and
Components
A. General System Component Identification
A Controller - Controls the operation of the system and displays
the product water quality. This system uses the micro-electronic
based CI-1000 controller.
B Reject Control Valve - Controls the amount of reject flow. A
separate reject recycle water control valve is included to regulate
waste water recovery.
C Pump Discharge Valve - Used to throttle the pump.
D Prefilter Pressure Gauges - Indicates the inlet and outlet pres-
sure of the prefilter. The difference between these two gauges is
the prefilter differential pressure.
E Pump Discharge Pressure Gauge - Indicates the pump dis-
charge pressure.
F Reject Pressure Gauge - Indicates the reject pressure.
G Reject Flow Meter - Indicates the reject flow rate in gallons per
minute (gpm). A reject recycle flow meter is also included.
H Product Flow Meter - Indicates the product flow rate in gallons
per minute (gpm).
I Prefilter Housing - Contains the RO prefilter.
J Automatic Inlet Valve - Opens when pump is on and closes
when the pump is off.
K Low-pressure Switch - Sends a signal to the controller if the
pump suction pressure is low.
L RO Feed Pump - Pressurizes the RO feed water.
M RO Membrane Vessels - Contains the RO membranes.
(See Figure 1)
Separate motor starter
enclosure used only with
CI 1000 controller.
Figure 1
Figure 1
3
B. Controller Drawing
Figure 2
CI-1000 Controller
4
III.Operation
A. Installation
1. The water supply should be sufficient to provide a minimum of
20 psig pressure at the design feed flow.
2. Proper pretreatment must be determined and installed prior to
the RO system.
3. A fused high voltage disconnect switch located within 10 feet of
the unit is recommended. This disconnect is not provided with
the RO system.
4. Responsibility for meeting local electrical and plumbing codes
lies with the owner /operator.
5. Install indoors in an area protected from freezing. Space allowances for the removal of the membranes from the pressure
vessels should be provided. This system requires 42" minimum
clear space on each side.
B. Plumbing Connections
Note: It is the responsibility of the end user to ensure that the
installation is done according to local codes and regulations.
1. Connect the pretreated feed water line to the inlet side of the
prefilter housing. (Figure # 1 item # 1) A feed water shutoff valve
should be located within 10 feet of the system.
2. Temporarily connect the outlet of the product water flow meter
to drain. (Figure # 1 item # 2) The product water line should
never be restricted. Membrane and/or system damage may occur if the product line is blocked.
3. Connect the outlet of the reject water flow meter to a drain. (Figure # 1 item # 3) The reject drain line should never be restricted.
Membrane and/or system damage may occur if the reject drain
line is blocked. An air gap must be located between the end
of the drain line and the drain. The use of a standpipe or other
open drain satisfies most state and local codes and allows for
visual inspection and sampling.
C. Electrical
Note: It is the responsibility of the end user to ensure that the
installation is done according to local codes and regulations.
1. A safety switch or fused disconnect should be installed within 10
feet of the system.
2. Verify that the disconnect switch is de-energized using a voltmeter.
3. Connect the outlet of the disconnect switch to the terminals on
top of the motor starter (Figure # 2). Attach the power supply
ground to the chassis ground. It may be necessary to drill a hole
in the enclosure and install a water tight strain relief or conduit
connector. The hole size and location must be determined by
the installer. Check the pump motor nameplate for the amperage draw at various voltages to determine the wire size required.
4. Do not apply power to the RO unit at this time.
D. Startup
1. Verify that the pretreatment equipment is installed and working
properly. Verify that no free chlorine is present in the feed water.
2. Verify that the on/off switch is in the off position.
3. Verify that the pump discharge valve (Figure # 1 item C) is open.
4. Install a 20" five micron filter cartridge in the prefilter housing.
(Figure #1 item I)
5. Open the reject control valve completely (Figure # 1 item B) by
turning it counterclockwise.
Close the reject recycle control valve completely if the reject
recycle option is included.
6. Open the feed water shutoff valve installed in step III-B-1 above.
7. Manually open the inlet solenoid valve (figure #1 item J) by turning the white lever located near the valve outlet.
8. Water will flow through the system and to drain through the
reject flow meter (figure # 1 item G).
9. Manually close the inlet solenoid valve after the air has been
purged from the system, or after 10 minutes, whichever occurs
first.
10. Close the pump discharge valve half way. (Figure # 1 item C)
11. Engage the safety switch or disconnect (installed in step III-C-1
above) to apply electrical power to the RO system.
12. On the CI-1000 controller, put the key switch in the on position
and press the start / stop button to turn the pump on. Press
the start / stop button again when the pump turns on to turn
the pump off and look at the motor fan as the pump stops to
determine if the pump rotation is correct. There is a 10 second
delay before the pump starts. See the controller section for more
details. The fan should rotate in the direction of the rotation
arrow located on the pump. Continue with the startup if the
pump is rotating in the proper direction. If the pump is rotating
backwards, change the rotation by disconnecting the power and
reversing any two of the wires on the power inlet. Verify proper
pump rotation before continuing.
13. Turn the system on.
14. Adjust the reject control valve(s) (figure # 1 item B) and the pump
discharge valve (Figure # 1 item C) until the desired flows are
achieved. Closing the reject valve increases the product flow and
decreases the reject flow. Opening the pump discharge valve
increases both the reject flow and the product flow. See the flow
rate guidelines and temperature correction table in the appendix
to determine the flow rates for different operating temperatures.
15. Allow the product water to flow to drain for 30 minutes.
16. Turn off the system and connect the product line to the point of
use. (Figure # 1 item # 2) The product water line should never be
restricted. Membrane and/or system damage may occur if the
product line is blocked.
17. Restart the system and record the initial operating data using the
log sheet in the next section.
Note: See the controller section of this manual for more
installation and operation information
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