2.1 SYSTEM ITEM DESCRIPTIONS (See Figure 1)
PRE-FILTER (#1): Consists of a 20” filter housing that contains a 10 micron sediment cartridge for
removal of particulate matter. The filter cap includes the feed water ¾” FPT inlet port.
PRESSURE VESSEL/MEMBRANE ASSEMBLY(s) (#2): This is where dissolved solids are sepa-
rated from the feed water. This assembly consists of 3 (6000) or 4 (8000) PVC pressure vessel(s)
that house the reverse osmosis (RO) membrane(s). PVC pressure vessels are standard on both
models. For optional pressure vessel construction, see 2.2 SYSTEM OPTIONS.
PUMP/MOTOR (#3): The multi-stage centrifugal pump boosts water pressure in the pressure
vessel/membrane assembly(s) to about 150 psig (10.3 bar) to ensure high solids rejection and high
flow rates. The motor is sized for the specific pump configuration and supply voltage requirement.
SOLENOID VALVE (#4): Electrically operated valve that prevents feed water from flowing through
the system when it is not in operation. The coil and body are separate replaceable units.
BRINE CONTROL VALVE (#5): A needle valve in the brine flowmeter that controls both the amount of
water flowing across the membrane(s) that goes to drain and membrane pressure.
RE-CIRCULATION VALVE (#6): A needle valve in the recirculation flow meter that controls the
amount of concentrate from the membrane to be re-circulated back into the feed stream. This
feature allows for higher recovery rates, see 3.2.2 OPERATING PARAMETERS for guidance. This
valve affects system operating pressure, brine flow rate and TDS.
PRE-FILTER IN/OUT GAUGES (#7): These gauges display the feed water pressure before and
after the sediment pre-filter. The operator can use this to observe pressure drop through the filter
as a means of detecting filter clogging to know when it is time to replace the element (See Section
7.4). For additional gauge options, see 2.2 SYSTEM OPTIONS.
VESSEL-IN/OUT GAUGES (#8): These gauges display the operating pressures at the inlet and
outlet of the membrane(s)/vessel(s). These pressures are used in the setup of the unit and as an
early warning of membrane fouling or degradation. For additional gauge options, see 2.2 SYSTEM
OPTIONS.
LOW PRESSURE SWITCH (#9): A pressure switch that shuts off the unit in the event of low feed
pressure (filter outlet). This is used as a pump protection device. It is factory set to cut off if the
pressure drops to 12 psi (0.8 bar). A minimum of 22 psi (1.5 bar) is required to originally start the
RO. The unit does not automatically restart if the loss of water pressure was temporary due to
some other water usage. It is necessary to evaluate the pressure loss situation, make the neces-
sary corrections and then restart the unit with the start switch (see #15 below).
MICROPROCESSOR CONTROLLER (#15) The PLC controls all functions of the RO System
including product conductivity monitoring. The PLC controls the RO system on/off from product
tank level, pre-treatment systems with auto backwash and from feed water pressure fault. This on/
off function controls the feed water solenoid valve and the main pump. An optional fast flush on
startup, tank full or at both times is also available. If the unit shuts down after turning the POWER
ON/OFF switch to ON it will be necessary to take corrective action. This condition may be due to
the feed water pressure momentarily dropping below the cutoff level and not recovering within the 2
second delay allowed by the controller. In this case it will be necessary to provide a higher capacity
feed to the RO system or to lower the low pressure cutoff switch setting. To adjust the low pressure
cutoff switch setting, see 7.1 LOW PRESSURE SWITCH ADJUSTMENT.
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