Before You Start: Turn off the Power
For safety, before you start doing any troubleshooting for an electric water heater, make sure you turn off the power. You can do this by turning off the fuse or circuit breaker connected to the heater unit.
When there’s no hot water
The problem can stem from a lack of power, a faulty electric thermostat or a faulty upper electric heating element. Start by ruling out power problems. First, reset any tripped circuit breaker, and replace any blown fuse. Next, check if power is being supplied to the electric water heating element thermostat. Test the element, and if it’s faulty, replace it. Finally, if the thermostat is receiving power but is still not working, replace it or the electric water heating element.
When the water’s not hot enough
The problem can be an undersized water heater, crossed hot and cold connections, or a faulty heating element or thermostat. To rule out an undersized heater, check to make sure the heater has 75 percent of its capacity as hot water. Next, rule out a crossed connection by turning off the water supply and turning on a hot water faucet; if the water still flows, look for a crossed connection. After this, check the lower and upper heating elements for power and electrical continuity and replace the element if necessary, being sure to clear any sediment first. Finally, if the elements are working, check the upper thermostat first and then the lower one and replace if either is not working.
When water is running too hot
It usually means the thermostat is set too high. Check to make sure the upper and lower thermostats are set between 110 and 140 degrees Fahrenheit.
