Thermo King MD-MT, Operator'S Manual

Page: 74 / 192

Electrical Maintenance
74
AC Components
Contactors
Test the contact points of the contactor by
checking the voltage drop across each set of
points when the contactor is energized and the
system is operating. If the voltage drop across a
set of points is more than 15 volts ac, replace the
contact points as a set.
Test the contactor coil by checking the voltage
across the coil. The contactor coil should be
energized by a minimum of 10 volts DC.
Overload Relay
The overload relay should open if the motor
circuit current draw is more than 12 amps for
380/460 volt systems or 24 amps for 200/230 volt
systems.
In-Cab TG-V Controller
Multi-Temp In-Cab TG-V
P/N 41-1548 — 12V
P/N 41-1549 — 24V
Figure 28: Multi-Temperature In-Cab TG-V
Controller
The In-Cab TG-V functions similarly to the
standard unit mounted TG-V. However, the
In-Cab TG-V Controller also has the following
additional features:
• Alarm Codes for Multi-Temperature In-Cab
TG-V
• Power Cord LED on Model 50 Units
• Whisper (Low Speed) Push Button
The operating manuals and the setup and
operating manuals contain information about the
control functions and how to customize the
display screens. Manuals for the Multi
Temperature In-Cab TG-V Controller: Operating
Manual (TK 40941) and Operating and Setup
Manual (TK 40805-1).
The same interconnecting harness (P/N 41-346) is
used for the Single Temperature In-Cab TG-V and
the Multi-Temp In-Cab TG-V.
A stand alone tester is available as P/N 204-831. It
will test all In-Cab TG-V Controllers.
Code 88 should be cleared with the tester before
declaring the microprocessor faulty.
CAUTION: The unit uses high voltage
alternating current (ac) during electric
operation. Lethal voltage potentials can
exist on connections in the high voltage
box. Take appropriate precautions and use
extreme care when testing the unit.
Alarm
Code
Fault Condition
03 Condensing Unit Return Air Sensor
Faulty
03A Remote Unit Return Air Sensor Faulty
14 Condensing Unit Defrost Circuit Failure
25 Battery Charging Alternator Failure
29 Defrost Initiation Failure
47 Remote Unit Defrost Circuit Failure
74 Cold Start or Checksum Error
75 Microprocessor RAM Faulty
76 Microprocessor EEPROM Faulty
77 EPROM Faulty
88 Microprocessor Faulty