Electrical Maintenance; Structural Maintenance; Remote Evaporator System Diagnosis - Thermo King T-500R Maintenance Manual

ELECTRICAL MAINTENANCE

SR-2/3 Multi-Temp Microprocessor Controlled Components
Refer to the Truck SR-2/3 Multi-Temp Diagnostic Manual TK 54293 for information about maintenance of the microprocessor
controlled components.
Unit Wiring
Inspect the unit wiring and wire harnesses during scheduled maintenance inspections for loose, chaffed or broken wires to protect
against unit malfunction due to opens or shorts.

STRUCTURAL MAINTENANCE

Unit Inspection
Inspect the unit during the unit pretrip inspection and scheduled maintenance inspections for loose or broken wires or hardware,
compressor oil leaks, or other physical damage which might affect unit performance and require repair or replacement of parts.
Defrost Drains
Clean the defrost drains during scheduled maintenance inspections to make sure the lines remain open.
Evaporator Coil
Clean the evaporator coil during scheduled maintenance inspections by blowing compressed air from the top side of the coil down
toward the bottom (the direction opposite the normal air flow). Inspect the coil and fins for damage, and repair if necessary.
CAUTION: Air pressure should not be high enough to damage the coil fins.

REMOTE EVAPORATOR SYSTEM DIAGNOSIS

Condition
Load temperature too high
Evaporator fan motor does not
run
Possible Cause
Refrigerant shortage
Setpoint too high
Expansion valve plugged
Partial obstruction in low side of
refrigeration system
Iced or dirty evaporator coil
Expansion valve open too much
Poor fitting trailer door
Liquid line solenoid partially closed
or defective
Evaporator fan not operating
Open in 2A circuit
Open in FM circuit
Open circuit between interface board
and expansion module
Defective fan motor
Defective expansion module
Remote Evaporators
Remedy
Repair leak and recharge
Adjust setpoint
Clean or replace
Locate obstruction and repair
Defrost or clean evaporator coil
Replace or adjust valve
Repair or replace doors
Repair or replace
Check and correct evaporator fan
Locate open and repair
Locate open and repair
Locate open and repair
Replace fan motor
Replace expansion module
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