The most common reason to remove air from the hot water heater is to cut energy and water costs. When there is air in the hot water heater, the heater must work ,and the water will actually get too hot to be used. More cold water than normal will be necessary to cool the water down. When you remove air from the tank, the water will heat as it should, and the regular amount of cold water will be required to cool it.
Put on the raincoat, rain trousers, goggles and rubber gloves. The water coming out of the hot water heater will be very hot and could cause burns if you are splashed by it.
Locate the drain valve at the bottom of the hot water heater. It will look similar to an outdoor spigot.
Place the bucket to catch the water under the drain valve.
Turn the drain valve handle counterclockwise until water starts coming out of the drain.
Allow the bucket to catch the water as it comes out. The water will sputter, and you will be able to hear and see when the air is passing through the drain.
Turn the drain valve handle clockwise to close it once the water stops sputtering.
Empty the bucket of water in a location that the hot water will not do any damage, such as the kitchen sink or possibly the basement floor drain.