TM 5-3810-231-12
b. Before starting heater, refer to paragraph 158
and assure that fuel line valve is open.
c. Start engine coolant heater in similar manner as
fresh air heaters (para 152). Operation of heater is
automatically controlled by a thermostat with a range
from 170 F. to 185 F. The coolant pump begins
circulation when light on heater control glows. This glow
indicates full operation of coolant heater.
154. Radiator Winter Front Shutter
a. The radiator winter front shutter is designed to
control flow of air through crane engine radiator by
positioning of shutters.
b. The shutter control lever is mounted on winter
front, and has three operating positions: open, half open,
and closed.
c. Refer to figure 95 for operating instructions of
winter front.
155. Heater Control boxes
The three heater control boxes are identical in
operation, and have three controls described below.
a. Indicator Light. The indicator light (fig. 92) has
two functions.
By depressing lens, operator may
determine power availability (para 152b(1)). Indicator
light glows constantly when heater is operating in either
LO or HI, and will continue to glow f or approximately
two minutes after heater i s turned OFF (while cooling).
Caution
Never attempt restart of heater while
light is glowing. Wait until light goes
Figure 95. Radiator winter front .
out, and avoid fire hazard.
c. Control Switch. The control switch (fig. 92) is a
b. Circuit Breaker Reset Button.
The circuit
three-position toggle switch with ON-HI (up), OFF
breaker (fig. 92) is a safety device installed in system to
(center), and ON-LO (down) used to select required
remove fire hazard of current overloads. To reset after
heater range.
tripping, press in on rest button.
156. Baffle Levers of Plenum Chambers
Caution
Pulling out on circuit breaker button
Each plenum chamber has a series of baffle
breaks all electrical circuits to heater.
levers to control amount and direction of heat to various
Do not stop heater operation with
connecting ducts. Instructions for movement of these
circuit breaker, for this will prevent
baffle levers is provided by an instruction plate mounted
heater from purging itself of fuel at
on each plenum chamber.
A typical chamber is
end of operating cycle.
illustrated in figure 93.
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