Thermo King 098203, Maintenance Manual

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Controller Description
Controller Description
The MP-4000 is an advanced microprocessor controller. It has been specially developed for the control
and monitoring of refrigeration units. The controller contains the following basic features:
Temperature/Message Status Display:
•Temperature area. Displays Return air sensor, Supply air sensor,
and Setpoint
• Message area. Displays Alarms, Message and Controller menu
Keypad:
• F1 – F4 Function keys navigate within the Status Display
• 2 Status LED indicators
• Special Function keys. ON/OFF, PTI, Defrost
Controller Back-up Battery
Every Controller has a Back-up Battery. This will allow the controller to be energized if the unit is not
connected to shore power. The technician can change settings in the controller - Setpoint, etc.
Press the ON/OFF key, the controller will energize and stay energized for 25 sec, by pressing any of the
Menu keys the 25 sec timer will reset to 20 sec.
Controller Input and Output Signals
The MP-4000 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 MP-4000 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
• Voltage measuring circuits
Output signals from the controller automatically regulate all unit functions including:
• Compressor operation
• Condenser fan operation