Pretrip

Pretrip Test verifies unit operation. This display allows a Pretrip Test to be selected and initiated by the operator. If the Pretrip Test is entered with the unit not running, a Full Pretrip Test with device amp checks will be performed. If the Pretrip Test is entered with the unit running in either diesel or electric mode, a Running Pretrip Test is performed. Test results are reported as PASS, CHECK, or FAIL when the Pretrip Test is completed.

Parent topic: Using the Main Menu

Pretrip Test Conditions

  • Current unit settings are saved and restored at the end of the Pretrip Test or if the unit is turned off and back on.

  • Pretrip Test can be run in either Diesel or Electric Mode.

  • The unit will auto switch from Diesel Mode to Electric Mode or from Electric Mode to Diesel Mode during a Pretrip Test if these features are enabled and the auto switch conditions occur.

Conditions Where Pretrip Tests Are Not Allowed

  • If any shutdown alarms are present. Pretrip tests are allowed with some Check and Log alarms.

  • If the unit is in Sleep Mode.

  • If the unit is in Service Test Mode, Output Test Mode, or Evacuation Mode.

Pretrip Test Considerations

When performing a Pretrip Test, the following issues should be considered:

  • If running a Pretrip Test on a trailer loaded with dry cargo, verify that proper airflow can occur around the load. If the load restricts airflow, false test results may occur. Also, these units have high refrigeration capacity which results in rapid temperature changes. Sensitive dry cargo may be damaged as a result.

  • If running a Pretrip Test on a trailer that has just been washed down, the extremely high humidity inside the trailer may result in false test results.

  • If running a Pretrip Test on a trailer loaded with sensitive cargo, monitor the load temperature during the test as normal temperature control is suspended during pre-trip operation.

  • Always perform Pretrip Tests with the trailer cargo doors closed to prevent false test failures.

Pretrip Test Sequence

Pretrip tests proceed in the order shown below. A Full Pretrip Test is started with the engine or electric motor not running and includes all tests. A Running Pretrip Test is started with the engine or electric motor running and does not include the Amp Checks or Engine Start Check.

  • Amp Checks: Each electrical control component is energized and the current drawn is confirmed as within specification.

  • Engine Start: The engine will start automatically.

  • Defrost: If the coil temperature is below 45 F (7 C), a defrost cycle is initiated.

  • RPM Check: The engine RPM in high and low speed is checked during the Cool Check.

  • Cool Check: The ability of the unit to cool in low speed is checked.

  • Heat Check: The ability of the unit to heat in low speed is checked.

  • Report Test Results: The test results are reported as PASS, CHECK, or FAIL when the Pretrip Test is completed. If test results are CHECK or FAIL alarm codes will exist to direct the technician to the source of the problem.