What is the difference between High and Low-density elements?
elements and thermostats A low density element tends to last longer. If you are filling a water heater make sure to let all of the air out of the water heater before turning on the electricity to it. It is a good idea to let the hot sides of faucets run for at least a few minute without seeing any air coming from the faucets before turning the electricity back on to the heater.