SECTION III. PRINCIPLES OF OPERATION
a. Control Panel. Control of the heater is provided by the control panel ON-OFF switch for starting and stopping. The
room thermostat controls the starting and stopping as the thermostat reaches its desired setting.
b. ECU Control. The ECU relay switching controls the blower motor, glow plug control, ignition pack control for
igniter, and receives flame switch and overheat switch conditions from the heat exchanger. If overheat switch opens,
heater will shut down; if flame switch closes, the glow plug will shut off.
Figure 1-4. Functional Block Diagram.