A burned-out heating element is among the more common problems associated with electric water heaters. Rheem manufactures electric water heaters with one heating element, or with two, mounted within the wall of the tank. If the tank features two elements and the heater produces only warm water, the top element probably requires replacement. If the heater instead produces only a short supply of hot water followed by cold water, the bottom element is probably defective. Whether you're replacing one or two elements, the process is the same.
Turn the water heater off.
Turn the cold water supply valve off. The valve is located above the tank.
Fasten a common garden hose to the tank's drain fitting, then open the fitting's handle and allow the water to drain into a floor drain. Remove the hose and close the fitting once the tank is empty.
Remove the two screws that secure the access panel to the side of the tank with a screwdriver, and pull the panel off the tank to reveal the insulation. Note that the tank will feature two access panels if the water heater is equipped with two heating elements.
Pull the insulation out of the water heater to reveal a crossbar that covers the thermostat bracket.
Twist the crossbar until it breaks away from the heater. The crossbar is used during the manufacturing process only. It cannot be replaced and will not affect the water heater.
Remove the thermostat bracket's two screws with a screwdriver and position the bracket away from the tank to reveal the heating element.
Loosen the screws that secure the thermostat's wires to the element, using a screwdriver, and pull the wires away from the element.
Twist the element counterclockwise with tongue-and-groove pliers until the element detaches from the tank, then withdraw the element from the tank.
Coat both sides of the element gasket included with the replacement element with pipe joint compound.
Slide the element gasket onto the back of the replacement element.
Slide the element into the water heater and tighten the element with tongue-and-groove pliers.
Position the thermostat wires around their screws on the element and tighten the screws to secure the wires in place.
Position the thermostat bracket over the tip of the element and tighten the bracket's retaining screws.
Press the "Reset" button on the thermostat.
Insert the insulation into the water heater.
Place the access cover(s) against the tank and tighten the cover's screws.
Open the cold water supply valve and turn the water heater on.