Watts PWR4011 User Manual
Installation, Operation
and Maintenance Manual
Wall Mounted Commercial Reverse Osmosis Systems
Series PWR4011
PURE WATER
!
CAUTION: Please read the entire manual before proceed-
ing 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 disconnect 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
II. Controls, Indicators, and Components
A. General System Component Identification – Figure #1 . . . . . . 3
B. Controller Drawing – Figure #2 . . . . . . . . . . . . . . . . . . . . . . . . 4
III. Operation
A. Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
B. Plumbing Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
C. Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
D. Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
E. Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
F. Operation and Maintenance Log . . . . . . . . . . . . . . . . . . . . . . . 5
G. Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
IV. Replacement Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
V. Membrane Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
VI. Appendix
Flow Rate Guidelines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Temperature Correction Factors . . . . . . . . . . . . . . . . . . . . . . . . . 8
Series PWR4011
IOM-WQ-PWR4011
Do not use with water that is microbiologically unsafe or
Note:
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
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.
RO Membrane
Feed Water Product Water
PWR40113012 PWR40113022 PWR40113032
Maximum Productivity
(gallons per day / gallons per
minute)
Maximum production based
on a feed water of 25°C, SDI
< 3, 1000 ppm TDS, and pH
8. Individual membrane productivity may vary (± 15%).
May be operated on other
feed waters with reduced
capacity.)
Quality (Typical Membrane
Percent Rejection)
Based on membrane manufactures specifications; overall system percent rejection
may be less.
Recovery (adjustable) 50 - 75 % 50 - 75 % 50 - 75 %
Membrane Size 4" x 40" 4" x 40" 4" x 40"
Number Of Membranes Per
Vessel
Pressure Vessel Array 1 1:1 1:1:1
Number Of Membranes 1 2 3
Prefilter (system ships with
one 5 micron cartridge)
Feed Water Connection 1" NPT 1" NPT 1" NPT
Product Water Connection 1/2" Tubing 1/2" Tubing 5/8" Tubing
Reject Water Connection 1/2" Tubing 1/2" Tubing 1/2" Tubing
Feed Water Required
(at 50% recovery)
Feed Water Pressure
(minimum)
Drain Required (maximum) 10 gpm 10 gpm 10 gpm
Electrical Requirement
(Other voltages available)
Motor Horse Power 1 1 1.5
Dimensions L x H x D
(inches)
Shipping Weight
(estimated pounds)
1800 / 1.25 3600 / 2.5 5400 / 3.75
98 % 98 % 98 %
1 1 1
10" BB 10" BB 10" BB
2.5 gpm 5 gpm 7.5 gpm
20 psi 20 psi 20 psi
120 VAC 60 Hz
18 amps
41 x 51 x 18 41 x 51 x 18 49 x 51 x 18
200 250 300
120 VAC 60 Hz
18 amps
120 VAC 60 Hz
27 amps
Reject Water
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 anti-scalant, 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 .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 reduction in recovery.
2
II. Controls, Indicators, and
Components
A. Controller - Controls the operation of the system.
B. Reject Control Valve - Controls the amount of reject flow.
C. Reject Recycle Control Valve – Controls the amount of recycle
flow.
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 Flow Meter - Indicates the reject flow rate in gallons per
minute (gpm).
G. Product Flow Meter - Indicates the product flow rate in gallons
per minute (gpm).
H. Prefilter Housing - Contains the RO prefilter.
I. Automatic Inlet Valve - Opens when pump is on and closes
when the pump is off.
J. Low Pressure Switch - Sends a signal to the controller if the
pump suction pressure is low.
K. RO Feed Pump - Pressurizes the RO feed water.
L. RO Membrane Vessels - Contains the RO membranes.
(See Figure 1)
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.
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 valve (Figure #
1 item I). 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 G) 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 F) 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.
Figure 1
3
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