When troubleshooting a residential electric water heater for incidents of either “No Hot Water” or “Insufficient Hot Water,” it is always a good idea to check the thermostat settings as well as the heating element(s) themselves.
To test for a burned out element, first, TURN OFF all electrical power to the water heater. Remove the cover panel(s) from the front of the heater and then disconnect the wires from the heating element terminals. Using a continuity tester, available from electrical supply houses, place one test probe on each of the element terminals. If there is no continuity, the element is defective and must be replaced. If there is continuity, proceed to the next step.
Place one test probe on one terminal of the element and one test probe to the element flange or tank shell to test for a grounded element. Repeat the test for the other element terminal. If either test shows continuity, the element is defective and must be replaced. Test any other elements, if applicable, in the same manner.
After these tests have been completed and any necessary elements replaced, reconnect terminal wires, replace cover panels, and make sure the tank is full of water before turning on power.
Before energizing the elements, be certain that the tank is completely filled with water by opening a hot water faucet. Once water flows from the hot water side of the faucet you ensure that all air has been purged from the tank and it is safe to energize the elements.
If the above procedure is not followed, the element may be partially submerged in water or, more likely, completely exposed in the “air pocket” and will be dryfired in a matter of seconds. Dryfired elements can be identified by a melted sheath or coil or copper colored or annealed sheath. Dryfired elements are not covered under warranty due to misuse and operation contrary to the installation instructions.