Pre-cooling allows you to make sure your trailer refrigeration unit is working and functioning properly. It is possible for units to run and not cool your trailer. Pre-cooling ensures your entire system is in check before you receive products.
Pre-cooling is one of the most important steps in the pre-loading stage of produce. It is absolutely essential for a refrigerated trailer to be pre-cooled. This becomes especially important during the summer months when temperatures, especially in the southern United States, can reach in the 100s °F. Failing to pre-cool a trailer will result in residual heat in the trailer, walls, ceiling, doors, and floor, which can affect the temperature of the product that is loaded in the trailer, and essentially heat the load.

How it works
Trailers must be pre-cooled to their correct requested product running temperature. Remember, this requested running temperature is always on CONTINUOUS setting. It takes up to 1 to 2 hours to pre-cool a trailer with the thermostat pre-set and the doors closed. This is critical to remember as pre-cooling trailers prior to arrival at pickup sheds will result in quicker loading times.

When preparing to pick up a load, the doors of the trailer must not be opened until the loading crews are ready to load it. Also, remember that just before the doors are opened to begin loading, the [b]transport refrigeration unit must be turned off[/b].

So remember, keep cool to ensure success at loading docks!