American electric water heater

Open the nearest hot water faucet, and fill the water heater until a steady stream of water flows out of the faucet. Once the water heater is completely filled, then shut off the faucet. Reset the heater. Turn the power off, then back on. Press the reset button on the control box. Wait 10 minutes.

Turn the power off to the water heater and remove the control box cover. Using a multi-meter, check the ohm resistance of the upper and lower heating elements between the blue and yellow wire connections (upper element) and the orange and blue wire connections (lower element). The ohm resistance should measure between 5-25 ohms. Replace the element if it does not measure 5-25 ohms., If the heating elements are okay, remove the thermistor plug from the control board. Using a multi-meter, measure the resistance between the red wires in the thermistor plug, then measure the resistance between the two black wires in the plug. Open a hot water faucet and measure the water temperature. If the water temperature is between 80 and 100 degrees Fahrenheit, the thermistor should measure between 50k-20k ohms; 100-120 degrees should measure 40k-15k ohms; 120-150 degrees should measure 30k-5k ohms. If the thermistors and heating elements are within ohm specification, replace the control board.

Shut off the house circuit breakers to disconnect electrical power from the water heater. Remove the control box cover and check the thermistor wire harness connection on the control board. Reconnect the wire harness plug if you find it loose or disconnected. If the wire harness connection is okay, unplug the thermistor wires and use a multimeter to measure resistance through the black wires that connect to the upper element thermistor. Next, measure the resistance through the red wires that connect to the lower element thermistor. Open a hot water faucet and measure the water temperature. If the water temperature is between 80 and 100 degrees Fahrenheit, the thermistor should measure between 50k-20k ohms; 100-120 degrees should measure 40k-15k ohms; 120-150 degrees should measure 30k-5k ohms. If you measure proper resistance through the thermistor circuits, replace the control board because the control board isn't detecting thermistor resistance correctly. If your meter measures infinite resistance through a thermistor circuit, check the wiring and repair or replace any damaged thermistor wiring. If thermistor wiring is okay, replace the thermistor.

Turn off power to the water heater and remove the control box cover. Inspect the yellow and blue wires connected to the relays for damage., Using a multi-meter, measure the resistance between the yellow and blue wires connected to the relays. The ohm resistance should be 5-25 ohms if the upper heating element is okay. If the upper heating element is defective, replace it. If the upper element and wiring are okay, replace the control board.

Turn off power to the water heater and remove the control box cover. Inspect the orange and blue wires connected to the control for damage., Using a multi-meter, measure the resistance between the orange and blue wires. The ohm resistance should be 5-25 ohms if the lower heating element is okay. If the lower heating element is defective, replace it. If the lower element and wiring is okay, replace the control board.

The water heater stops working due to a malfunction in the control board. Reset the unit by turning off power and waiting 10 minutes. If the green light is still flashing 6 times after resetting the control, replace the control board.