Thermo King 098916, Руководство по обслуживанию

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47
Operating Instructions
Unit On/Off Switch
The unit control box has a two position toggle
switch to turn power On or Off to the unit.
• On position. Unit will operate on Cool or
Heat depending on the controller setpoint
temperature and the container air temperature.
• Off position. The unit will not operate.
Sequence Of Operation
Unit Start-up
A 60 second sequence start of the required loads
occurs during initial start-up of the controller. If
cooling (or heating) is required, the unit operates
in the Cool (or Heat) mode.
• When the Unit On/Off switch is turned On,
the LED display turns on and then off.
• The setpoint appears briefly in the LED
display.
NOTE: When the setpoint appears in the LED
display, both the Return and Supply LEDs are
lit.
• The LED then shows the controlling air sensor
temperature.
• The controller energizes the heater relay for 5
seconds and senses the incoming power phase
and selects the correct power phase to unit
components.
• The evaporator fan motors start about 40
seconds after the unit is turned on.
• Evaporator fans operate on high speed at
setpoints of -9.9 C (14.1 F) and above.
• Evaporator fans operate on low speed at
setpoint temperatures of -10 C (14 F) and
below.
• The compressor starts about 10 seconds later
and the liquid line solenoid energizes (opens)
if the controller calls for cooling.
• The condenser fan then starts if the condenser
temperature requires condenser fan operation.
• If the controller calls for heating, the electric
heaters are pulsed on and off to provide heat.
• The controller turns on the In-range LED
when the controlling sensor temperature is
within 1.5 C (2.7 F) of the setpoint.
NOTE: Random time delays during the initial
unit start-up minimize peak current draw.
Controller Input and Output
Signals
The MP-3000a microprocessor controls all unit
functions to maintain the cargo at the proper
temperature. The controller also monitors and
records system faults and performs pretrip.
The MPC-3000a controller uses advanced
solid-state integrated circuits to monitor and
control unit functions. The controller monitors
inputs from:
• Return Air Sensor
• Supply Air Sensor
• Evaporator Coil Sensor
• Condenser Coil Sensor
• Ambient Sensor
• Humidity Sensor
• USDA (Spare) Sensors 1, 2 and 3
• Compressor Discharge Line Temperature
Sensor
• High Pressure Cutout Switch/Discharge
Pressure Sensor
• Low Pressure Cutout Switch/Suction Pressure
Sensor
• Phase measuring circuits
• Current measuring circuits
1 Unit On/Off Switch
Figure 26: Unit On/Off Switch
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