Thermo King 098916, Maintenance Manual

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Specifications
24
MP-3000a Controller Specifications
Temperature Controller:
Type
MP-3000a microprocessor with thermostat, digital thermometer,
programming keypad, mode indicators, LED display and LCD
display for displaying unit operating and cargo information
Setpoint Range -35.0 to +30.0 C (-31.0 to +86.0 F)
Digital Temperature Display -60.0 to +80.0 C (-76.0 to +176.0 F)
Controller Software (Original Equipment):
Version See controller identification decal
Defrost Initiation:
Evaporator Coil Sensor
• Manual Switch or Demand Defrost Initiation: Coil must be
below 18 C (65 F). Defrost cycle starts when technician or
controller requests defrost initiation.
• Timed Defrost Initiation: Coil must be below 10 C (50 F).
Defrost cycle starts 1 minute after the hour immediately following
a defrost timer request for defrost initiation. For example, if the
defrost timer requests a defrost cycle at 7:35, the defrost cycle
will start at 8:01. Datalogger will record a Defrost event for each
interval in which a Defrost cycle is pending or active (i.e. both the
8:00 and 9:00 data logs).
Demand Defrost
Demand defrost function initiates defrost when:
• Temperature difference between the return air sensor and
defrost (evaporator coil) sensor is too large for 90 minutes
• Temperature difference between the left hand and right hand
supply air sensors is too large and unit has operated for 90
minutes since last defrost
• Temperature difference between the supply air sensors and
return air sensor is too large
Defrost Timer:
Chilled mode
• Supply Temperature at 5.1 C (41.2 F) or Above: Every 8 hours
of compressor operation.
• Supply Temperature at 5.0 C (41.0 F) or Below: Every 2.5
hours of compressor operation. Defrost interval increases 0.5
hours each timed defrost interval. Defrost synchronization
creates step intervals of 3, 4, 4, 5, 5, 6, 6 and 7 hours. Maximum
time interval in Chilled mode is 7 hours.
Frozen mode
Every 8 hours of compressor operation. Defrost interval increases 2
hours each timed defrost interval. Maximum time interval in Frozen
mode is 24 hours.
Reset to Base Time
Defrost timer resets if the unit is off more than 12 hours, setpoint is
changed more than 5 C (9 F) or PTI pretrip test occurs.
Defrost Termination:
Defrost (Coil) Sensor
Chilled mode: Terminates defrost when coil sensor temperature
rises to 30 C (86 F); or exceeds 18 C (65 F) for 35 minutes/45
minutes if voltage is less than 440 volts.
Frozen mode: Terminates defrost when coil sensor temperature
rises to 30 C (86 F); or exceeds 8 C (46 F) for 35 minutes/45
minutes if voltage is less than 440 volts.
Termination Timer
Terminates defrost after 90 minutes at 60 HZ operation if coil
sensor has not terminated defrost (120 minutes at 50 Hz operation)
Power Off Turning Unit On/Off switch Off terminates defrost