Watts PWR8024 User Manual
Installation, Operation
and Maintenance Manual
Commercial Reverse Osmosis Systems
Series PWR8024
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. Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
C. Pre-treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
II. Controls, Indicators, and Components
A. General System Component Identification – Figure #1 . . . . . . 3
B. Electrical Connection – 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 . . . . . . . . . . . . . . . . . . . . . . . 7
G. Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9
IV. Replacement Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
V. Membrane Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
VI. Appendix
Flow Rate Guidelines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Temperature Correction Factors . . . . . . . . . . . . . . . . . . . . . . . . 11
IOM-WQ-PWR8024
Series PWR8024
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
MODEL NUMBER PWR80243085 PWR80243125 PWR80243165 PWR80243205
Maximum Productivity (gallons per minute) 40 60 80 100
Quality (typical membrane percent rejection) 99%
Recovery (adjustable) 65% - 75%
Membrane Size 8" x 40"
Membrane Array (four elements per vessel) 1:1 2:1 2:2 3:2
Prefilter (system ships with five micron cartridges) 7 round x 40" 7 round x 40"
Feed Water Connection 2" Flange 2.5" Flange 3" Flange
Product Water Connection 2" Flange 2.5" Flange
Reject Water Connection 1.5" Flange
Feed Water Required (GPM at 65% recovery) 62 93 123 154
Minimum Feed Water Pressure 20 PSIG 20 PSIG 20 PSIG 20 PSIG
Drain Required (maximum) 62 93 123 154
460 VAC, 3-phase, 60Hz (other voltages available) 25 amps 30 amps 35 amps 40 amps
Motor Horse Power (TEFC Motor) 15 20 25 30
Dimensions L x W x H (approximate) 186" x 26" x 72"
Shipping Weight (estimated pounds) 2500 2800 3200 3500
Notes:
• Maximum production based on a feed water of 77° F, SDI < 3,
1000 ppm TDS, and pH 7.6.
Individual membrane productivity may vary (± 15%). May be
operated on other feed waters with reduced capacity.
• Percent Rejection is based on membrane manufactures specifi-
cations; overall system percent rejection may be less.
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
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.
B Reject Control Valve - Controls the amount of reject flow.
C Reject Recycle Control Valve – Controls the amount of reject
recycle flow.
D Pump Discharge Valve - Used to throttle the pump.
E Prefilter Inlet Pressure Gauge - Indicates the inlet pressure of the
prefilter.
F Pump Suction Pressure Gauge – Indicates the prefilter outlet
and pump suction pressure. The difference between this gauge
and the prefilter inlet gauge is the prefilter differential pressure of
the prefilter.
G Pump Discharge Pressure Gauge - Indicates the pump dis-
charge pressure.
H Membrane Feed Pressure Gauge – Indicates the membrane
feed pressure.
I Reject Pressure Gauge - Indicates the reject pressure.
J Reject Flow Meter - Indicates the reject flow rate in gallons per
minute (gpm).
K Reject Recycle Flow Meter – Indicates the reject recycle flow in
gpm.
L Product Flow Meter - Indicates the product flow rate in (gpm).
M Prefilter Housing - Contains the RO prefilters.
N Automatic Inlet Valve - Opens when pump is on and closes
when the pump is off.
O RO Feed Pump - Pressurizes the RO feed water.
P RO Membrane Vessels - Contains the RO membranes.
Q Motor starter / transformer enclosure.
(See Figure 1)
Figure 1
3
B. Electrical Connection
460 Volt 3-phase
Power Inlet
To Pump
Figure 2
Electrical Connection
4
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