130
TK 56171-2-OP-EN
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Stop the unit if the compartment temperature remains higher than the
desired temperature range from the setpoint on two consecutive 30 minute
inspections. Contact the nearest Thermo King Service Center or your
company office immediately. Take all necessary steps to protect and
maintain proper load temperature.
Table 2.
Inspection Troubleshooting
Problem: A return air temperature reading is not within desired
temperature range of the setpoint.
Cause
Remedy
The unit has not had
time to cool down to
correct
temperature.
Refer to the load log history. Look for above temperature load
records, properly pre-cooled cargo compartment, length of time on
road, etc. Correct as required. Continue monitoring return air
temperature until the reading is witin the desired temperature
range of the setpoint.
The unit may have a
low refrigerant
charge.
Check the receiver tank sight glass for refrigerant level. If fluid is
not showing in the receiver tank sight glass, the refrigerant charge
may be low. A competent refrigeration technician is required to add
refrigerant or repair the system. Contact the nearest Thermo King
dealer, authorized Service Center, or call the Thermo King Cold Line
for referral. Consult the Table of Contents for Cold Line information.
The unit is in defrost
or has just
completed a defrost
cycle.
Monitor the return air temperature after the defrost cycle is
completed to see if the temperature returns to the desired
temperature range of the setpoint.
The evaporator is
plugged with frost.
Initiate a manual defrost cycle. The defrost cycle will automatically
terminate when complete. Continue monitoring the return air
temperature until the reading is within the desired temperature
range of the setpoint.
Improper air
circulation in the
cargo compartment.
Inspect the unit and cargo compartment to determine if the
evaporator fan(3) are working properly circulation the air. Poor air
circulation may be due to improper loading of the cargo, shifting of
the load, or fan belt slippage. Correct as required. Continue
monitoring return air temperature until problem is corrected.
