Like all household appliances, tankless water heaters need to be repaired at times. Most commonly done is repairing the heating element. For a professional, this can be an easy process. Turn off the unit, drain excess hot water, and remove the wires at the top with a screwdriver. Carefully, the element is removed, and the new O ring and element are placed. Finally, reattach the top wires, clean any spills, and you’re ready to go!