Shipping with reefer containers requires a lot of attention to ensure safety for cargo in transit. All reefer boxes, therefore, must pass a thorough Pre-Trip Inspection (PTI) prior to each time of stuffing.

The PTI is actually an extensive check of both the container and the machinery. This inspection ensures that the reefer machinery is running properly at correct settings and that the container body is clean and undamaged.

Shippers might not care much about PTI, because that’s usually shipping companies’ job. In some cases, however, shippers own reefer containers (SOC) and need to do PTI themselves or use the service of equipment-handling contractors. In any way, it is useful for customers to have general ideas about how the container inspection is carried out before they can stuff cargo.

Specific sequence in PTI procedures for reefer containers may vary a little bit among shipping companies. Yet PTI basically include following steps, which can be kept as check procedures for reference.

Before Power On

General inspection (Ensure unit and components are free from physical damage and are not missing (Box, Contactors, Cable, Plug, Compressor, Loosen wire, etc.).

Check Cleanliness: No extra labels, Cargo Debris/Remnants.

Check Refrigerant and Lubricant.

Inspect Partlow: Ensure chart drive is rewound and battery level is in range.

Check electric insulation value (compressor, motors, heaters).

After power on

Ensure phase correction contactors are in function (Measure and record voltage).

Check of serviceability of engine:
Ensure no abnormal noises components;
Ensure fan and blower are in proper direction;
Initiate LPPP (CFII), FPT (Smart), LPP (MHI), Auto PTI (Micro link) or FPTI(MPC);
Detect proper working unit at reaching set-point;
Calibrate sensors and Partlow element.

Check RV%.

Preset temperature setting to –18°C:
Initiate and check that the unit goes into manual defrost and complete cycle;
Check cleanliness of drains.
Record oil level directly after defrost.
Upon temperature reach to –18°C and unit is running in full cool.

Measure compressor pressure.

Measure currents (Compressor, Cond. Fan motor, Evap. Motor, heater).

Detect proper working unit at reaching set-point –18°C check Freon level.

Set temp to 0°C and run – Switch off upon reaching 0°C temp.

Upon unit reaching to 0°C, record and calibrate sensors and Partlow element.

Final check

Switch off unit on/off switch, leave power selection switch to 380/440V.

Ensure doors locked secure (reefer, controller box, Partlow, etc.).

It’s worth noting that above content is only the guideline and should not replace or override PTI procedures recommended by the manufacturer of a particular refer container or the procedures set up by an individual shipping company.