When the frost in your upright freezer reaches a thickness of 1/4 an inch, it's time to defrost it. You should defrost and clean this appliance out at least one time a year, according to Whirlpool's customer help website. Defrosting your upright freezer helps it run more efficiently. It also helps reduce freezer burn on your foods. It's not difficult to defrost your freezer, but it does take plenty of time, especially if your freezer is full of food.
Unplug or shut off the freezer. Prop the door open. Remove the food. Wrap each item in layers of newspaper to help keep it frozen. Then, cover the wrapped food with blankets for extra insulation while the freezer is defrosting.
Remove the grill on the back side of the base of the upright freezer. Grab it at each end and pull it off.
Locate the drain tube--a piece of rubber tubing--which should be protruding from underneath the freezer. Grab the end and pull it out; place the end in a large pan.
Remove the drain plug, which is located on the freezer's bottom floor.
Place pans of hot water on the freezer shelves to help melt the frost faster. Set up an electric fan in front of the freezer to help speed up the process. Once the frost begins to melt, use a plastic scraper to carefully remove it. Remove the water pans when the water is no longer hot and replace them, then remove them entirely once the frost has melted sufficiently.
Dry the walls, floor and shelves of the upright freezer with towels, then replace the drain plug. Take the drain tube out of the pan and replace it under the freezer.
Replace the grill by lining up the clips with their corresponding openings on the freezer; snap it back into place. Close the door, and turn the freezer back on.
Let the freezer run for six to eight hours, according to Whirlpool's customer service website, before filling it with frozen food. Wait 24 hours before filling it completely, so the freezer has adequate time to cool itself down and keep the food frozen.
After the freezer is turned back on, it will run constantly for several hours to bring the temperature down to the appropriate level.
Only use a plastic scraper that came with your freezer, or is designed to be used in a freezer, to remove the frost. Using a sharp or harder object can damage the interior walls. Keep an eye on the drain pan during the defrosting process. Dump it as needed so it doesn't overflow.