Pre-load Operation

Parent topic: Unit Operation

Pre-Trip Conditions

To properly perform a Full Pretrip Test, the following conditions must exist:

Pre-Trip Checks

  1. With unit connected to the proper power supply, turn the power supply On/Off switch to ON.

  2. Switch refrigeration unit On/Off key to ON position. A sequence start of the required loads occursduring initial start-up on cooling:

    • Controller senses the incoming power phase and selects the correct power phase to unit components.

    • Evaporator fan motors start and operate on low speed.

    • R-134a compressor and condenser fan then start and the liquid line solenoid energizes (opens).

    • R-23 compressor starts 30 seconds later.

    Note If one or both compressors fail to start, turn the On/Off key OFF. Then repeat steps 1 and 2. If the unit still does not start, refer to “Alarm Codes, Descriptions and Corrective Actions” in the Microprocessor Controller chapter of this manual. Be sure to wait up to 1 minute for both compressors to start.

  3. Adjust controller setpoint to the desired temperature:

    Note The setpoint temperature can be set between -10 C and -70 C (14 F and -94 F) in either F or C using the C/F key. Just press and hold the F/C key (to display the alternate temperature scale).

    • Press SETPOINT key to display cursor flashing in the “TEMP SETP” line.

    • Press F3 key to enter new setpoint.

    • With correct setpoint in display, press and hold F4. Controller places new setpoint in controller memory and shows new setpoint in LCD display.

    Note New setpoint must be between -10 C and -70 C (14 F and -94 F) or controller will return to the previous setpoint display.
    Note If the F4 key is not pressed within 30 seconds, the controller will default (return) to the previous setpoint. If this occurs, repeat step 3.

  4. Check the direction of the condenser airflow (see “Condenser Fan and Evaporator Fan Rotation” in the Electrical Maintenance chapter of this manual).

  5. Check direction of evaporator airflow (see “Condenser Fan and Evaporator Fan Rotation” in Electrical Maintenance chapter of this manual).

  6. Allow the unit to operate one-half hour before loading. This will remove residual container heat and moisture, and pre-cool the container interior.

  7. Perform a Pretrip (PTI) Test and check unit modes while the unit pre-cools:

      Caution
    • Service procedure
    • The PTI test should only be performed on an empty container!
    Note Correct all existing alarm conditions and clear the alarm codes before performing a PTI test. The controller will automatically clear all existing alarms before beginning the PTI test.

    • Press PTI key to enter PTI menu.

    • Select PTI.

    • Press F4 to start the PTI (Pretrip) Test.

    • The controller then performs the Pretrip Test.

    • Observe the unit for proper operation and functions during pretrip test.

    • LCD display shows PTI Test currently being performed. PTI test ends automatically. Press any key on the controller to return the unit to normal operation.

    • If an operating problem occurs during the Pretrip Test, the Alarm LED will turn ON and FLASH. An “E” may also appear in the right side of the LED display. View and correct any alarm conditions. Then clear (acknowledge) the Alarm Code(s) and repeat the PTI Test.

    Note Clear the Alarm codes ONLY after the alarm codes are documented and problems repaired. A permanent record of the alarm codes remains stored in the datalogger memory for retrieval via DRU-II or SmartSponge handheld data retriever.

  8. top the unit by moving the On/Off key to the OFF position.