How to Install an Apcom WH10A Thermostat

Apcom manufactures WH10A thermostats.

Install an Apcom WH10A ThermostatInstall an Apcom WH10A Thermostat
The WH10A thermostat controls the upper element in a two element electric water heater. Apcom's WH10A has teardrop-shaped wire terminals. When the Apcom WH10A's terminal screws tighten against a wire, it forces the wire into the narrow portion of the tear drop. The WH10A contains an upper-limit safety switch, which automatically trips if the water temperature in the tank rises above 180 degrees Fahrenheit. For accurate temperature readings the Apcom WH10A thermostat must install directly against the water heater's tank.

Flip the electric water heater's circuit breaker to the "Off" position. The label on the circuit breaker should read "Water heater."

Hold the Apcom WH10A against the water heater's tank above the upper heating element. Slide the bottom half of the WH10A down into the U-shaped clip that extends up from the upper element. The clip grips the tabs on the sides of the thermostat and holds the back of the thermostat tight against the tank. The top half of the WH10A contains the red high-limit switch button.

Loosen the Apcom WH10A's top left terminal screw, labeled "1," with a Phillips screwdriver. Push the black electric-supply wire that extends from the top of the water heater into this terminal and tighten the terminal screw. The wires from the circuit breaker enter the top of the water heater where they connect to the two thermostat electric-supply wires that feed power to the WH10A.

Loosen the Apcom WH10A's top right terminal screw, labeled "3," with the Phillips screwdriver. Push the other electric-supply wire, colored either red or white, into this terminal and tighten the terminal screw.

Loosen the Apcom WH10A's bottom left terminal screw, labeled "2," with the Phillips screwdriver. Push the short upper heating element wire into this terminal and tighten the terminal screw.

Loosen the Apcom WH10A's middle right terminal screw, labeled "4," with the Phillips screwdriver. Push the remaining top heating element wire and one of the bottom thermostat wires into this terminal and tighten the terminal screw. The WH10A has two terminals labeled "4." The top "4" terminal stays hot at all times and the bottom "4" terminal turns hot when the WH10A's internal switch flips from terminal "2" to terminal "4."

Loosen the Apcom WH10A's bottom right terminal screw, labeled "4," with the Phillips screwdriver. Push the remaining bottom thermostat wire into this terminal and tighten the terminal screw.

Things You Will Need

  • Phillips screwdriver

About the Author

Based out of Central Florida, Robert Sylvus has been writing how-to and outdoor sports articles for various online publications since 2008. Sylvus has been a home improvement contractor since 1992. He is a certified HVAC universal technician.