Watts R12-0150, Installation And Operation Manual

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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 - These foulants should be removed to less than 0.1 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.
I. 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 (optional) - 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 (optional) - Indicates the reject flow rate in gallons per minute
(gpm).
H. Product Flow Meter (optional) - 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.