Reefer loads: pre-cool, continuous run, and the temperature log that settles the claim

Notes from the yard — published September 3, 2026 by the dispatch desk at Long Road Transportation.

Continuous run or cycle-sentry

A reefer unit runs one of two ways, and picking the wrong one is a quiet, expensive mistake.

Continuous run keeps the engine going the whole trip. It holds tight tolerances and it is what frozen product and pharmaceuticals require. It burns more fuel and that is the point.

Cycle-sentry starts and stops the unit automatically to save fuel, which is fine for produce and other loads with a wider band. The catch is that it leans on the battery for every restart. A weak battery can let the unit stall overnight and fail to restart, and the box drifts out of range silently while the driver sleeps. On any load where the tolerance is narrow, continuous run is the cheaper option in the end.

Pre-cool is not a formality

The trailer is brought down to the set point before loading, not after. Loading into a warm box means the unit spends the first hours pulling heat out of the trailer walls and the pallets at the same time, and the product spends those hours out of range.

The other half of it is the product itself. A reefer maintains the temperature it receives. Product loaded warm arrives warm, and the temperature record will show exactly that — which is usually the moment a claim against the carrier turns into a conversation with the shipper.

What FSMA expects on file

The Sanitary Transportation rule turns good practice into documentation. For food loads that means:

• Documented verification that the trailer was pre-cooled.
• Washout and sanitation tickets for the trailer.
• A continuous temperature log running from pre-cool through delivery, not spot readings.
• Sensor calibration records.
• Written corrective action on any temperature excursion — the excursion itself is survivable, an undocumented one is not.

The recorder is the defence

When product is rejected at the dock, the argument is settled by a timestamped record or it is not settled at all. A continuous log from pre-cool to delivery either demonstrates the load was held correctly or it identifies precisely when and where it was not.

That is why we log the whole trip rather than the delivery, and why the set point, the mode and the pre-cool time are confirmed with the shipper in writing before the doors close. Reefer work runs on the same long-haul fleet as our dry van and open-deck freight, out of Kent and Tacoma.

Questions we get asked

Should I ask for continuous run or cycle-sentry?

Continuous run for frozen, pharmaceutical, or anything with a narrow tolerance. Cycle-sentry is acceptable for loads with a wider band, but it depends on the unit restarting reliably every cycle.

Does the reefer cool the product down?

No. It holds the temperature it is given. Product has to be at temperature when it is loaded, into a trailer that was already pre-cooled.

What do I get if there is a temperature claim?

A continuous, timestamped temperature record covering pre-cool through delivery, plus the set point and mode agreed before loading.

Read next

• Liftgate, residential and limited access: what the delivery site costs you
• What changes when the carrier owns the chassis

Long Road Transportation is an asset-based carrier operating its own trucks, chassis and heavy-haul equipment out of Kent and Tacoma, Washington. USDOT 3388302, MC 113242, SCAC LRDP.