Electric
resistance water heaters operate by resistance elements within the water
containment tank. These units can be equipped with either one or two elements.
Most models have two elements, one located in the upper portion, and one in
the lower portion of the tank. Each element has an individual thermostat control
found behind the access plates. This is important to remember because when adjusting
the tank's temperature, both thermostats must be adjusted, not just one.
As
previously described, hot water is drawn from the top of the tank and replaced
by cold water entering at the bottom through a tube.
When the demand for hot water is low, the lower heating element operates
to maintain the water temperature. As hot water demand increases, the upper
heating element comes on to maintain the water temperature. Hot water is drawn
from the top of the tank, the top element turns off, and the lower element comes
back on to maintain the set temperature.
