Electric hot water heaters are relatively simple devices that normally give years of trouble-free service. The most common problems occur with the heating elements. A hot water heating element works by resisting the electrical current flowing through it, which causes the element to get hot. That heat is then transferred to the water. Corrosion can build up on the elements and reduce the efficiency of the heat transfer process. The elements can also burn out or short. If electricity can't flow through the element, it can't heat water. You can test the heating elements with a multimeter while they are still installed in the tank.
Things You'll Need
Turn off the power to the water heater.
Remove the screws on the heating element access panel and open the panel. Check the power leads with a multimeter to make sure all power to the unit has been disconnected.
Push aside the insulation. Locate the wires running to the heating element. Unscrew the wires from the heating element terminal connectors. Move the wires to the side so they no longer touch the connectors.
Set the multimeter to low range ohms. Check the meter by connecting the test probes together, which should result in a reading of zero or no resistance. Connect each of the test probes to a different terminal on the heating element and take a reading. If the meter reads very high or infinite resistance, the element has failed and will need to be replaced.
Test the second heating element of your water heater in the same manner if it is so equipped.
Tips & Warnings
- A heavily corroded element may test okay electrically, but have such poor heat transfer that it appears nonfunctional. Try removing the element and cleaning it carefully with sandpaper to see if its performance improves.
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