Thermo King 098203, Maintenance Manual

Page: 213 / 264

Diagnosis: Troubleshooting, Warnings and Alarm Codes
211
Troubleshooting Refrigeration Problems
Condition Possible Cause Remedy
Load temperature too high—
unit not cooling Compressor does not operate See “Mechanical Diagnosis”
Controller setpoint too high Adjust controller setpoint
Defective container insulation or poor
fitting doors
Repair container
Shortage of refrigerant Repair leak and recharge
Overcharge of refrigerant Purge system
Air in refrigeration system Evacuate and recharge
Vapor injection valve open
Check vapor injection valve circuit
and compressor discharge
temperature sensor
Too much compressor oil in system
Remove compressor oil from
compressor
Iced or dirty evaporator coil Defrost or clean evaporator coil
Restricted lines on high side Clear restriction
Plugged filter drier/in-line filter Change filter drier
Compressor Digital Control Valve
defective
Replace defective valve
Condenser coil dirty or airflow
restricted
Clean condenser coil, clear
restriction, or repair or replace fan
motor or condenser fan blade
No water flow to water-cooled
condenser Restore water flow to water-cooled
condenser-receiver tank
Defective water pressure switch
(Option)
Replace switch
Expansion valve open too much Adjust or replace valve
Expansion valve power element lost
its charge
Replace power element
Expansion valve feeler bulb
improperly mounted, poorly insulated
or making poor contact
Correct feeler bulb installation
Head pressure too low
NOTE: This unit has a digital
capacity control system. Suction and
discharge pressures may drop below
expected normal readings when the
unit is in Modulation Cool (control
temperature within 10 C [18 F] of
setpoint or in Power Limit mode).
Shortage of refrigerant Repair leak and recharge
Low ambient air temperature No remedy
Service gauge out of calibration Replace gauge