TM 55-1925-282-14&P
0002 00
SYSTEM CONTROLLERS
The system controllers monitor, start, and stop all processes required by the ROWPU system. It is the central
electrical connection point in the system. It also serves as the safeguard to ensure that only potable product
water is allowed to pass into the product water storage tanks. The controller monitors the salt content of the
product water by means of the salinity probe, and it signals the 3-way diverter valve when potable water is being
produced. The three-way diverter valve and pump motors are all directly connected to, and controlled by, the
System Controller. The system controllers also monitor and sense signals from the low and high pressure
shutdown switches and halt system operation when an alarm condition exists. Finally, the controllers have an
hour meter that displays the total use hours of the system. This assists in following regular scheduled mainte-
nance by keeping track of the 500 hour increments.
The technical characteristics of the system controllers are contained in table 6.
Table 6. System Controllers Technical Characteristics
Item
Data
Manufacturer ................................................................................................. Sea Recovery Corporation
Model ................................................................................................................................. B595800007
Voltages .............................................................................................. 440 Vac, 60 Hz, 3 phase, 24 Vdc
MEDIA FILTER
The media filter contains a graduated media filter bed made of fine sand substrate. The sand traps suspended
solids larger than 30 microns. This provides protection and longer life to the 20-micron filter element. The
substrate sand in the media filter requires infrequent change due to the ability to backflush and rinse the media
filter substrate. During backflushing, the media filter is completely isolated from the rest of the ROWPU, while
raw water cleans and flushes debris overboard.
Backflushing alters the direction of raw water flow inside the media filter. This allows the substrate to be purged
of the filtered contents if the media filter becomes clogged. The inlet pressure gauge is the first indication that raw
water is available to the ROWPU. The raw water inlet pressure should normally be about 40 PSI (2.8 bar). Inlet
pressure should never exceed 50 PSI (3.4 bar) or damage to the ROWPU could occur. After backflushing, the
media filter is rinsed to change out the raw water. If necessary, the media filter can be bypassed. However, this
will shorten the life of the 20-micron filter.
The media filter outlet pressure gauge provides an indication of raw water differential pressure across the media
filter. A media filter outlet pressure gauge reading 20 PSI (1.4 bar) lower than the media filter inlet gauge indicates
that the media filter is clogged. Backflushing the media filter regularly will prevent excessive differential pressure.
The technical characteristics of the media filter are contained in table 7.
Table 7. Media Filter Technical Characteristics
Item
Data
Manufacturer .................................................................... Water & Power, Inc. (The Watermaker Store)
Model ................................................................................................................................. B071080002
Type ............................................................................................................ Back Washable Sand Filter
Rated Capacity ................................................................................. 16 gallons (60.6 liters) per minute
Maximum Pressure ....................................................................................................... 50 PSI (3.4 bar)
Continuous Working Pressure ...................................................................................... 40 PSI (2.8 bar)
0002 00-5