Enroute Inspections

Complete the following enroute inspection every four hours. This will help minimize temperature related problems.

Parent topic: Loading and Inspection Procedures

Inspection Procedure

  1. Verify setpoint is correct.

  2. Check the return air temperature reading. It should be within the desired temperature range.

  3. Initiate a manual defrost cycle after each enroute inspection.

Inspection Troubleshooting

  1. If a temperature reading is not within the desired temperature range, refer to the troubleshooting table ( Inspection Troubleshooting). Correct problem as required.

  2. Repeat the Enroute Inspection every 30 minutes until the compartment temperature is within the desired temperature range. Stop the unit if the compartment temperature is not within the desired temperature range on two consecutive 30 minute inspections, especially if the compartment temperature appears to be moving away from the setpoint.

  3. Immediately contact the nearest Thermo King or FRIGOBLOCK Dealer or your company office.

  4. Take all necessary steps to protect and maintain proper load temperature.

      5. Notice
    • Cargo Loss
    • 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 or FRIGOBLOCK Dealer or your company office immediately. Take all necessary steps to protect and maintain proper load temperature.

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 within the desired temperature range of the setpoint.
Note Ensure cargo is properly pre-cooled prior to loading onto trailer. If 'warm cargo' is loaded onto trailer 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 trailer compartment.
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 dealer, authorized Service Center, or refer to Emergency Assistance section for contact 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 depending on unit, fan belt slippage or faulty electrical fans. Correct as required. Continue monitoring return air temperature until problem is corrected.
The unit did not start automatically. Determine the cause for not starting. Correct as required. Continue monitoring return air temperature until reading is within desired temperature range of the setpoint.

Multi-Temp Units Only– The unit is being used to cool/heat a single temperature load and does not have the capacity to cool the entire trailer.

A multi-temperature unit may not have the cooling or heating capacity to maintain a specific temperature range throughout an entire trailer.