62-12259 4–4
If alarm 00129 Check Engine Coolant Sensor is active, the ambient temperature sensor will be used. If both
alarm 00129 Check Engine Coolant Sensor and alarm 00121 Check Ambient Air Sensor are active the control
system assumes a temperature of less than 32°F (0°C) for the preheat timing.
During the last five seconds of preheat OR for five seconds before a start attempt, if no preheat is required, the
buzzer (B) is energized; then the starter solenoid contactor (SSC) will be energized for a maximum of ten seconds
while the engine condition is checked during the cranking period. The engine is considered to be running, and the
start sequence will be stopped, when engine speed is greater than 1000 rpm and the engine oil pressure switch
(ENOPS) is closed.
During the second and third attempts, the control system will monitor additional inputs.
• When engine speed reading is less than 1000 rpm, ambient temperature is above 32°F (0°C) and the ENOPS
is closed, alarm 00130 Check Engine RPM Sensor will be activated and the engine will be considered run-
ning.
• When engine speed reading is less than 1000 rpm, ambient temperature is below 32°F (0°C), the ENOPS is
closed and DC current is more than 2 amps,
alarm 00130 Check Engine RPM Sensor
will be activated and
the engine will be considered running.
Once the engine is considered running, the control system will keep the preheater energized for an additional 0 to
180 seconds of Post Heat, depending on engine coolant temperature (refer to Table 5–1).
During the start sequence the control system monitors engine speed while cranking. If engine speed drops below
50 rpm for three seconds the starter solenoid contactor will be de-energized and alarm
00035 Check Starter Cir-
cuit
will be activated.
If the unit fails to start after three attempts, alarm
00031 Failed to Start - Auto Mode
will be activated.
If the unit is equipped with a fuel heater, the control system will monitor ambient temperature. If ambient is below
77°F (25°C) the fuel heater relay (FHR) will be energized. Energizing FHR closes its normally open contacts to
supply power to the fuel heater temperature switch (FHTS) to the heater. Refer to Section 2.7 for FHTS settings.
4.4.2 Transition to High Speed
After a successful start, the control system may call for the engine to transition to high speed. When high speed is
required, the main microprocessor will provide a signal through the CAN system to the ECU, calling for the speed
change. Three factors control this transition.
• First: Transition may be delayed if a time value is entered in the HIGH SPEED DELAY Configuration. The
delay may be set to 0 to 10 minutes. The factory default setting is 1 minute.
• Second: If the engine is started when the coolant temperature is 79°F (26°C) or below it will remain in low
speed until the coolant temperature reaches 79°F (26°C) or it has operated for a minimum of 15 seconds.
Once the coolant temperature reaches 79°F (26°C) the engine may transition to high speed.
• Third: Transition will be based on the need for temperature control. Generally, the engine will operate in high
speed when the unit is in Pulldown or Pull-Up mode (full capacity required) and in low speed when less than full
capacity is required.
4.5 Start-Stop Operation
Start-Stop is provided to reduce fuel or power consumption. This feature allows full automatic control of the unit by
monitoring compartment temperature, battery condition and (when in Engine Operation) engine coolant tempera-
ture.
The main function of Start-Stop Operation is to shutdown the engine or compressor after certain conditions are met
(to provide an efficient temperature control system) and to initiate a restart sequence after certain conditions are
met. The Start-Stop/Continuous key is pressed to select between Continuous and Start-Stop Operation. The mode
of operation will be indicated in the status bar.
NOTE
The control system may be locked so that the unit will always operate in Start-Stop whenever the set-
point is within a specific range. Refer to Range Lock (Section 4.9.2) for additional information.
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