Loading and Enroute Inspections
41
Inspection Troubleshooting
Problem
Cause
Remedy
A return air
temperature
reading is not
within desired
temperature
range of the
setpoint.
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
within the desired temperature range of the setpoint.
NOTE: Ensure cargo is properly pre-cooled prior to loading onto truck. If 'warm
cargo' is loaded onto truck and reefer is used to cool to setpoint this will result in
longer time required to cool down to correct temperature and possibly plugging of
evaporator with frost due to increased humidity in truck compartment.
The unit may have
a low refrigerant
charge.
Check the receiver tank sight glass for refrigerant level. If liquid 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.
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.