Most electric hot water heaters use two elements to keep the water inside the tank hot. The bottom element is the primary, heating the water continually. The upper element periodically heats the water to help maintain the heat. Electric hot water heater element replacement is the same for either element.
Which Element To Replace
Electric hot water heater element replacement does require knowing which element is at fault. Although the best way to determine the faulty element is with an ohm meter, most homeowners should be able to tell simply by the amount of hot water. If the same amount of hot water is running but the water is only lukewarm, chances are the upper element requires replacement. If the hot water simply goes cold after a few minutes, the bottom element is faulty. Another way to ensure you replace the faulty element is to go ahead and replace both at the same time.
Drain The Tank
Before beginning your electric hot water heater element replacement, turn off the power to the unit. Go to your home electrical panel box and turn off the circuit breaker. Close the cold water supply valve that is usually at the top of the tank on the house supply pipe coming from the wall. Once the power and water is off, you can begin draining the tank. Even if you are just replacing the upper element, now is a good time to drain the tank completely. This will help to remove any built-up sediment in the tank.
Thread a garden hose onto the drain valve at the bottom of the hot water tank. Set the opposite end of the drain hose outside or in a nearby bathtub or utility sink. Turn the drain valve knob counterclockwise to allow the water to drain through the hose. Locate the nearest faucet to the electric hot water heater and turn on the hot water. This helps to drain the tank a little quicker and will aid in removing air from the tank when you refill it. Once the water stops draining, turn the drain valve handle clockwise to close the drain. Remove the garden hose from the drain valve.
Remove Faulty Elements
Remove the upper and lower access panels on the side of the electric hot water heater. Each is held onto the tank with two screws. Peel back the insulation to reveal the thermostat and the end of the heating element. The heating element is above the thermostat and has two wires connecting to two terminal screws. The element end will either be round and screw into the tank, or have a square plate that has two bolts securing it to the tank.
Loosen the wire terminal screws tow complete turns with a screwdriver and pull the wires off the screws. Turn the round type heating element counterclockwise with a large socket wrench and remove it from the tank. Remove the bolts securing the mounting plate with the socket wrench, if your element has the square mounting plate. Pull the element out of the electric hot water tank.
Take the elements with you to a home improvement center or plumbing supply shop to purchase replacements. It is important to purchase heating elements that are the same watt, voltage and length as the previous elements. Purchase a small can of pipe dope rated for hot water heaters as well.
Install New Heating Elements
Clean the threads where the heating element installs with a toothbrush and rag. This will remove some of the mineral deposits and scale that has built up. Apply pipe dope to the threads inside the electric hot water tank as well as the threads on the heating element. The key to a successful electric hot water heater element replacement is to have no leaks around the new element. Thread the element into the hot water tank. Tighten the element securely with the large socket wrench. For those with the square mounting plate, coat the threads of the mounting bolts with pipe dope and secure the plate with a socket wrench to secure the heating element.
Loosen the terminal screws with the screwdriver. Hook the bare ends of the wires over the neck of the screws and tighten the screws. Open up the cold water valve and allow the electric hot water heater tank to fill with water. The faucet you have open will spurt water and air during the filling process. Once there is a steady flow of water coming out of the faucet, turn the faucet off.
When you hear the water heater is full, look around the area of the heating elements for leaks. The pipe dope forms a seal around the threads and makes a water tight seal. Push the insulation over the thermostat and heating element once you verify there are no leaks. Attach the access panel covers back onto the side of the unit. Turn on the circuit breaker to power the electric hot water heater. A nice hot shower is the best reward for a successful electric hot water heater element replacement.