Reefer Trouble: What a Driver Can Check Before It Costs a Load

A reefer alarm on a loaded trailer is different from most breakdowns because the cargo is on a clock. Temperature-sensitive freight does not wait for a convenient repair window.

Here is what a driver can usefully check and where the line is.

First, know what the alarm actually says

Reefer units log codes and display them. A code tells you which system is complaining, and that determines urgency. Some alarms are advisory and the unit keeps running. Some shut it down.

Write the code down before clearing anything. It is the most useful piece of information anybody helping you will ask for.

The obvious checks

• Fuel level in the reefer tank, which is separate from the tractor and gets forgotten
• The unit is actually set to run and to the right setpoint and mode
• Return and discharge air temperatures, which tell you whether it is actually cooling
• Airflow — is the load stacked so air can circulate, are the return air openings blocked
• Doors and seals, because a door not sealing means the unit runs constantly and never catches up
• Belts and obvious leaks in the unit
• The condenser and evaporator coils for debris packing

Blocked airflow is the most common cause of a trailer that will not hold temperature with a unit that is working perfectly. Freight loaded to the ceiling against the return air opening starves the unit.

Fuel is the one that surprises people

The reefer has its own tank and its own consumption, and a unit running continuously in Florida heat burns through it faster than anyone plans for. Running the reefer tank dry means the same priming problem any diesel has after running out.

Check it when you fuel the tractor, not when the alarm goes off.

If the unit has shut down on a loaded trailer, the clock started when it stopped. Do not spend an hour troubleshooting before calling somebody. Check the obvious things, then get help moving while you keep looking.

Temperature that will not come down

A unit that runs constantly and never reaches setpoint usually points at airflow, a door seal, a refrigerant problem, or a load that was warm when it was loaded.

That last one is worth saying. A reefer is designed to hold temperature, not to pull down a load that arrived warm. If freight was loaded above setpoint, the unit may never catch up.

What needs somebody with tools

Refrigerant work, compressor problems, electrical faults in the unit, control board issues and anything requiring gauges. Those are not roadside driver jobs and attempting them generally makes the situation worse.

Documenting it

Temperature records matter on a claim. If a unit failed and the load is in question, the download from the unit and any manual temperature checks are the evidence.

Note the time the alarm appeared, the code, what you checked and when help was called.

Prevention

Pre-trip the reefer the way you pre-trip the truck — fuel, belts, coils clear, door seals, and a run test before loading. Most reefer failures on the road were visible in the yard.

Coils packed with debris are the classic one. A unit that cannot reject heat cannot cool, and in a panhandle August that margin disappears fast.

Running on standby

Units that can run on electric standby save fuel and wear when the trailer is sitting at a dock or a yard with power available. Plenty of drivers never use it because nobody showed them.

It is worth knowing whether your unit has it and how to switch over, particularly on long dock waits in summer.

Pre-cooling the trailer

A trailer loaded warm and then cooled is a load fighting the unit from the start. Pre-cooling the box before loading, where the shipper allows it, changes whether the unit ever catches up.

It also matters for the temperature record, which is what a claim gets argued over.

Hour meters and service

Reefer units have their own service intervals based on running hours, and those hours accumulate fast in Florida summer where the unit rarely cycles off.

A unit that has gone well past a service interval is a unit that fails on a load rather than in a yard. The hour meter is worth reading occasionally.

If you have a reefer down with a loaded trailer, call (850) 495-0366. Dispatch is answered 24 hours a day and we come to the trailer wherever it is sitting in the panhandle.