Operation · Run Modes
Continuous Run vs. Start/Stop: Choosing How the Unit Runs
Run the pre-trip, then match the mode to the cargo. Tightest control or lowest fuel — here's how to choose, plus Intellisets.
- Pre-trip
- Continuous run
- Auto start/stop
- Intellisets
Load's in, doors shut — now the unit needs to know how to run. Modern TRUs offer modes that trade temperature precision against fuel, emissions, and engine wear. Pick right, and run a pre-trip first.
Pre-trip: check before you commit
A pre-trip is a comprehensive self-test the control system runs to verify the unit and flag failures. Run one before loading, while you can still act on a problem.
- START/RUN/OFF to RUN; press MENU until PRETRIP shows.
- Press PRETRIP to open the menu (it times out in ~15 s).
- Select Start Pretrip and confirm.
7–15 min
How long the pre-trip self-tests take to run
PASS / FAIL
Summary screen; FAIL holds until alarms are cleared
Review found alarms (VIEW ALARMS) and every test result (TEST RESULTS). Clear and correct any alarms before you trust the unit with a load.
Continuous run vs. automatic start/stop
Mode AContinuous Run
Tightest control
Runs nonstop. Holds within about 0.5°F of setpoint — best for very sensitive product or constant-airflow loads. Supply-air control helps prevent top freezing. Cost: 100% engine run time, more fuel, hours, and maintenance.
Mode BAuto Start/Stop
Most efficient
Cycles like a home fridge: pulls to setpoint, shuts off, restarts when box air warms to a set point. Cuts run time, fuel, emissions, and maintenance. Restart programmable 0.5°F–18°F (default 5.4°F). Load's thermal mass keeps product steady while air cycles.
The reassuring part of start/stop: the unit controls the air temperature, which swings as it cycles — but the load's thermal mass means the actual product temperature barely moves. For most loads, that's exactly right.
Switching modes
With the switch in RUN, press the START-STOP / CONTINUOUS key until the mode you want is highlighted. A confirmation ("START/STOP MODE SELECTED" or "CONTINUOUS RUN MODE SELECTED") shows for about 10 seconds.
Intellisets: presets that kill guesswork
Rather than configuring by hand each time, many units support Intellisets — preset profiles per commodity. Think of the popcorn button on a microwave: one press loads the right settings.
44
Separate Intellisets a fleet can customize and pre-program
3 keys
Press "=", arrow to the profile, press "=" to activate
Run the pre-trip while you can still fix what it finds. A failed pre-trip on the yard is a service ticket; the same failure 400 miles out is a claim.
— AVRO PartsChoosing the mode
- Continuous run for sensitive product needing tight control or constant airflow — when you'll spend the fuel.
- Auto start/stop for most loads — thermal mass keeps product steady, fuel savings are real.
- Intellisets to lock in the right profile per commodity and cut operator error.
- Always set mode and setpoint to the shipper's written instructions.
Bottom line
Pre-trip first, then match the mode to the cargo. Last in the series: setpoints, defrost cycles, and the data that proves you held temperature.
Keep the controller and driveline pre-trip ready.
OEM-spec controllers, sensors, and driveline parts that keep your unit passing pre-trip and running the mode you set.
General reference based on AVRO field experience, Carrier Transicold service guidance, FSMA (21 CFR Parts 1 & 11), and USDA Handbook 669. This is not legal advice and is not a comprehensive FSMA summary. Specs and procedures change — confirm current requirements with your authorized dealer and shipper specifications before servicing or shipping. © 2026 AVRO Parts. All rights reserved.