Watts PWR25113021, PWR25112011, PWR25111011, PWR25113011 Installation, Operation And Maintenance Manual
Installation, Operation
and Maintenance Manual
Wall Mounted Commercial Reverse Osmosis Systems
Series PWR2511
PURE WATER
!
WARNING
Please read carefully before proceeding with
installation. 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.
Keep this Manual for future reference.
• 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 ..................3
III. Operation
A. Installation........................................ 3
B. Plumbing Connections .............................. 3
C. Electrical Connections .............................. 4
D. Startup .......................................... 4
E. Control Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
F. Operation and Maintenance Log .......................5
G. Troubleshooting ...................................6
IV. Replacement Parts List...............................7
V. Membrane Replacement .............................7
VI. Appendix ..........................................7
Temperature Correction Factors .........................7
Limited Warranty ..................................... 8
Note: Do not use with water that is microbiologically unsafe or
of unknown quality without adequate disinfection before or after
the system.
Series PWR2511
IOM-WQ-PWR2511
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. It is critical to maintain adequate reject
flow in order to prevent membrane scaling and/or fouling.
RO Membrane
Feed Water
Reject Water
Product Water
PWR25111011 PWR25112011 PWR25113011 PWR25113021
Maximum Productivity
(gallons per day)
Quality
(membrane rejection)
Recovery
(user adjustable)
Membrane Size 2.5" x 14" 2.5" x 21" 2.5" x 40" 2.5" x 40"
Number Of Membranes 1 1 1 2
Dimensions W x H x D
(approximate inches)
Prefilter
(system ships with one
5 micron cartridge)
Feed Water Connection
Product Water
Connection (tubing OD)
Reject Water
Connection (tubing OD)
Feed Water Required
(maximum)
Feed Water Pressure
(minimum)
Drain Required
(maximum)
Electrical Requirement 120 VAC 60 Hz 8 amps
Motor Horse Power
Shipping Weight
(estimated pounds)
150 250 600 1200
98 % 98 % 98 % 98 %
15 - 75 % 15 - 75% 15 - 75 % 30 - 75 %
22 x 32 x 12 22 x 52 x 12
10"
1
⁄2" NPT
3
⁄8"
3
⁄8"
2.4 gpm
20psi
2.4 gpm
1
⁄2
50 50 60 70
Notes:
• Maximum production based on a feed water of 77°F, SDI < 3, 1000 ppm TDS,
and pH 8.
Individual membrane productivity may vary (± 15%). May be operated on other
feed waters with reduced capacity.
• Percent Rejection is based on membrane manufactures specifications; overall
system percent rejection may be less.
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 antiscalents 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. If the
feed water has zero hardness, the pH can be raised to eliminate
CO2.
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 (See Figure 1)
A On / Off Switch – Turns the unit on and off.
B Product Pressure Switch – Automatically turns
the unit on and off based on the product water
pressure.
C Reject Control Valve - Controls the amount of
reject flow.
D Reject Recycle Control Valve – Controls the
amount of recycle flow.
E Prefilter Pressure Gauges - Indicate the inlet and
outlet pressures of the prefilter. The difference
between these two gauges is the prefilter
differential pressure.
F Pump Discharge Pressure Gauge - Indicates the
membrane feed pressure.
G Reject Flow Meter - Indicates the reject flow rate
in gallons per minute (gpm).
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 RO Feed Pump - Pressurizes the RO feed water.
L RO Membrane Vessel(s) - Contains the RO
membrane(s).
M Low-pressure indicator.
G
M
Figure 1
L
3
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