Water Heater Thermostat Replacement, A Step By Step Guide
The water heater thermostat is the device that turns the source of heat on and
off to produce and maintain the home's supply of hot water. The device consists of a bimetal switch that
opens and closes based on the expansion and contraction of the metal. The device can be adjusted to
maintain the desired hot water temperature. It is a simple matter of turning the pointer on the unit
with a small standard screwdriver until it is on the desired water temperature.
When the temperature of the water in the storage tank is below the thermostat's
setpoint, the switch is closed. This supplies electrical power to the element.
As current flows through the element, heat is produced and transferred to the
water in the tank.
When the water temperature reaches the setpoint, the bimetal in the switch
deforms and opens the electrical contacts. This interrupts power to the element and stops current flow
and the production of heat.
**NOTE** ONLY YOU CAN ASSESS YOUR ABILITY TO PERFORM THE FOLLOWING TASKS. THIS IS A
GUIDE AND CANNOT PROVIDE ALL OF THE DETAILS FOR EVERY SITUATION.
The typical home's water heater will have two thermostats and they are referred
to as the upper and lower thermostats. They are not identical. The upper unit typically has three wire
connections while the lower unit only has two.
Smaller units such as for apartments will only have one thermostat.