Water heaters
Water heaters are just big pressurized water tanks with heating elements and temperature sensors inside them. Many are dual stage to provide more efficient operation, with cool water flowing from the bottom and hot water pulled from the top, with two elements heating both areas when necessary.1 Water heaters use anodes to attract contaminants in the water. Sacrificial anodes are destroyed by this process and should be replaced every 3 years or so, while powered anodes use electricity to attract particulates and last longer. Water heaters should be flushed every six months to a year, with variance allowed for water quality and hardness.