Electric Water Heater Inspection

Introduction
The electric water heater uses two immersion heating elements, one near the top of the tank and one near the bottom to heat the water.  The heating elements are electrical-resistant elements that operate in a similar fashion to an electric stove-heating element.  The unit is powered by a 220-volt circuit.

Heating Elements and Controls
Each heating element has a thermostatic switch that turns the individual heating element on and off.  Both thermostatic switches are usually set to the same temperature.  When the water temperature (at the top or bottom) drops below the preset limit, a control switch closes to create an electrical circuit through the heating element.  The electric current heats the element, thereby heating the water.  When the water temperature reaches its preset limit again, the heating element will turn off.  Thermostats are adjustable and are set between 120°F for increased energy savings and scald protection.

Lower and Upper Heating Elements
The lower element maintains the water temperature in the tank (when idle) because the water at the bottom of the tank will cool first (heat rises).  In addition, the lower element heats the cold water entering the tank through the dip tube (when hot water is being drawn out of the top of the tank).

When the lower heating element cannot keep the water being drawn of the top of the tank hot (e.g. high hot water demand), the upper element activates and will try to heat the warmer water at the top tank as it is drawn.  Note: most electric water heaters are designed so that both elements will NOT work at the same time.  The lower element will shut off when the upper element is active.