TB 9-6115-644-13
Section III. PRINCIPLES OF OPERATION
1-13
GENERAL.
This section contains functional description of the winterization kit.
1-13.1 Functional Description. When the heater is switched on, the indicator lamp comes on, the combustion air fan
comes on high, then low, and the start cycle begins. The water-circulating pump begins to run and after a short time, the fuel
pump begins to operate. The fuel is ignited by the ignition element and a flame detector turns off the ignition element when
combustion is established. When the coolant temperature has reached the operating point, the temperature sensor sends a
signal to the control unit to reduce the heat output. If the temperature remains at the upper limit, the heater turns off, but the
coolant pump continues to run. The heater will automatically restart once the system's temperature has dropped to the lower
temperature switch point of the sensor. The heater continues in this mode until the ON/OFF switch is placed in the OFF
position. At this point the indicator lamp will go off, but the combustion air blower and the circulating pump will continue
running for several minutes and then shut off.
NOTE
Heater warms generator engine block sufficiently to start.
(1) The circulation pump, ceramic igniter/glow plug, and combustion air fan start operation after the heater is turned on.
(2) After approximately 50 seconds, the fuel pump starts, combustion starts, and the ceramic igniter/glow plug is turned
off.
(3) When the coolant temperature reaches 176F (80C), the heater switches to low heat mode.
(4) If coolant temperature drops to 158F (70C), the heater switches to high heat mode.
(5) If coolant temperature rises to 185F (85C), the heater will switch off (coolant pump continues to run).
(6) The heater continues to run as described above until the ON/OFF switch is placed in the OFF position.
(7) When switched off, the fuel pump stops and the flame is extinguished. The combustion air fan and coolant
circulation pump continues to run for a cool down period of several minutes.
1-5/(1-6 BLANK)
