Duck
Sarcastic remark goes here
The air chute across the ceiling carries the cold air to the rear, then it flows across the freight & gets sucked back into the unit down near the floor in front.
When in a dock, the refrigerated air is blown straight into the warehouse. Most loading areas are kept at temps in the 30's or 40's so if your set point is below that, you are using your reefer fuel to cool their warehouse while drawing in their warmer air across the freight in the trailer.
These places that tell you to keep your reefer on while in the dock are just trying to get free refrigeration for their facility.
And because you are giving them free refrigeration, they have one less reason to hurry up & get you loaded or unloaded.
I never give customers free refrigeration.
In fact, I shut off the unit before I even open the doors because when you have the doors open & the unit running, you're just sucking in outside air. If it is hot outside you are thawing the load. If it's humid outside you're bringing in moisture that will freeze & cover the freight with frost.
Why don't the carriers teach this to their drivers?
If I owned a reefer fleet I'd have pin-switches installed on the right trailer door that shuts off the unit when the doors are open. And my drivers would be instructed that when asked by a customer about it, to say "providing refrigeration for your warehouse is not included in the rate".
When in a dock, the refrigerated air is blown straight into the warehouse. Most loading areas are kept at temps in the 30's or 40's so if your set point is below that, you are using your reefer fuel to cool their warehouse while drawing in their warmer air across the freight in the trailer.
These places that tell you to keep your reefer on while in the dock are just trying to get free refrigeration for their facility.
And because you are giving them free refrigeration, they have one less reason to hurry up & get you loaded or unloaded.
I never give customers free refrigeration.
In fact, I shut off the unit before I even open the doors because when you have the doors open & the unit running, you're just sucking in outside air. If it is hot outside you are thawing the load. If it's humid outside you're bringing in moisture that will freeze & cover the freight with frost.
Why don't the carriers teach this to their drivers?
If I owned a reefer fleet I'd have pin-switches installed on the right trailer door that shuts off the unit when the doors are open. And my drivers would be instructed that when asked by a customer about it, to say "providing refrigeration for your warehouse is not included in the rate".