Figure 71.11. Space heater flow diagram.
the liquid heater system. Refer to paragraph 151 for
system. Each system consists of a blower motor, fan,
and the necessary air passages.
a. Fresh Air System. To circulate fresh air for
161. Electrical System
heating and distribution to the compartment, the fresh
air fan draws air through the opening at the rear of the
heater. The fresh air passes over and cools the motors,
The space heater is similar to the liquid heater
then passes around the burner unit and through a
electrical system described in paragraph 152 with the
passageway between the combustion chamber and the
exceptions of the pump switch and personnel heater and
inner wall of a secondary heat exchanger. It also
defroster switch which are omitted and the variations in
passes between the heater outer casing and the outer
the internal wiring (fig. 71.12 for the wiring diagram).
wall of the heat exchanger.
b. Combustion Air System. Air for the combustion
162. Motor-Generator Set
chamber enters the heater through the larger opening in
the heater base, passes through the combustion air
blower shell and into the burner. The air mixes with the
A 115 volt ac electric motor coupled to a 24 volt dc
fuel vapor in the burner, and combustion occurs.
generator provides an electrical source to maintain the
Contaminated combustion air passes through parts at
vehicle storage batteries at full charge while operating
the far end of the combustion chamber, into the
the winterization kit with the truck engine at rest.
secondary heat exchanger, and leaves the heater
Facility electrical source to operate the motor is
through the centrally located exhaust opening.
connected to the vehicle by a 50-foot cable. The
generator is protected from damage caused by
160. Fuel System
excessive current draw by a 30 amp circuit breaker. A
reverse current relay prevents current draw from the
battery when the electric motor is not operating.
The fuel system for the space heater is identical to