How Do I Determine Which Element I Need for My Electric Water Heater?
If you run out of hot water faster than you used to, have only lukewarm water or no hot water at all, it is possible that one of the elements needs to be replaced. How to accurately diagnose a faulty element is a topic of another post. This post assumes you have already determined that you need new elements. It discusses how to determine which element you need and how to replace them.
There are two types of elements found in the majority of water heaters: a flanged element or a screw-in threaded element. There are some other types on older heaters, but they are becoming very rare.
Flanged Element
Screw-in Element
Socket Wrench
Always turn off the power supply to the water heater and drain the water from the tank before working with the elements. Most water heaters have two elements while some have only one. The elements are located on the side of the tank behind a metal plate attached with one or two screws. Remove the plate. There will be two wires attached to the element. Loosen the screws and remove the wires. Don’t worry about remembering which wire went to each screw, it doesn’t matter. It will now be obvious which element you have. If you see four bolts, it is a flanged element. Remove the bolts and pull the element straight out. If you have a screw-in element, you will see a single large hex head on the element. A 1 ½” deep socket can be used to remove the element or you can purchase an element socket wrench.
The wattage and voltage will be printed on the head of the element. Some elements will have two different listings such as 3500W at 208V and 4500W at 240V. Use the larger number when ordering. You may want to replace both elements while you have the tank drained, even if only one is bad now.
Important reminder! After installing the new element, always refill the tank with water before turning the power back on. Open a faucet while you fill the tank to be sure there are no air pockets remaining inside the water heater. Since elements are made to be submersed in water, they will burn out in seconds if you turn on the power to the tank before it fills completely.
Other informational sources:
- A diagram of hot water tanks – from HowStuffWorks.com
- Good video on replacing an element.
- Another source of how to change an element from Ehow.com