indications on the control consoles. You, the GSE, must
view A.) The four indicator lights, the heater switch, and
also locate and repair all faults that occur to the control
the changeover switch are mounted through the back of
box. Refer to chapter 5 for additional information on
the box and protrude through the instrument panel. On
troubleshooting the filter/coalescer electrical control
the CG-47 class ship, the electrical control box is located
box.
in front of the instrument panel. Notice that the electrical
control box in figure 4-2, view B, does not have a heater
switch.
Fuel Service Heaters
MAINTENANCE.-- The electrical control box for
The fuel service heaters on the DDG-51 class ships
the filter/coalescers is nothing more than an electrical
are of the electrical type. One fuel heater is installed in
controller. You will maintain the electrical control box
each fuel service system. All fuel service heaters are
i n the same manner as you would any electrical
located downstream from the fuel pumps. Each heater
controller. Routine maintenance on the control box
operates on 440 volts ac, 60 Hz, 3 phase and is rated at
i n c l u d e s cleaning, inspecting, and testing. Proper
180 kilowatts (kW) and 236 amps. The fuel outlet
preventive maintenance reduces the chance of failure of
temperature from the heater is regulated by a solid-state
the filter/coalescer electrical control box. Routine PMS
heater controller.
includes keeping the insulation resistance of the control
circuits high and making sure the electrical connections
The fuel heaters are electrically interlocked with the
are tight. Because of its location, there is the chance that
fuel service pumps. The heaters will not operate until a
fuel oil can enter the control box, causing short circuits
fuel service pump is operating. The heater control
and fires. When performing PMS, make sure you
circuitry may be energized, however, before a fuel
remove all fuel residue from inside the control box. Any
service pump is started. This condition will be shown by
problems found in the control box must be corrected
a green CONTROL ON indicating light. (See fig. 4-3.)
immediately. Make sure you follow the proper electrical
When the fuel service pump is started, the heater will
safety precautions whenever you perform maintenance
automatically start operating. This will be shown by a
on this unit.
green HEATER ON indicating light on the heater
controller.
TROUBLESHOOTING.-- During PMS on the
f i l t e r / c o a l e s c e r electrical control box, you must
MAINTENANCE.-- The fuel service system heater
troubleshoot the control box whenever malfunctions
controller is maintained in the same way as any other
occur. A fault in the control box is usually caused by
controller. The difference in this controller is that it
short circuits, open circuits, or grounds. The control box
contains solid-state devices. The routine maintenance
has a mechanical interface with the shifting mechanism.
on the heater controller, however, is the same as it would
Sometimes the shifting mechanism and the
be on any electrical controller. This routine maintenance
m i c r o s w i t c h e s become misaligned, causing false
i n c l u d e s cleaning, inspecting, and testing. Proper
Figure 4-3.--Fuel service system heater controller.
4-4
