If your electric water heater has suddenly stopped producing hot water and you have checked the power supply and heating elements, replacing the upper and lower thermostats may get you back in the shower again.
Step 1: Use the circuit breaker or fuse in the home’s electrical panel to shut off the power supply to the water heater.
Step 2: Remove top access panel to reveal the upper thermostat.
Step 3: Remove the plastic safety cover from the thermostat.
Step 4: Use a voltage sensor to confirm the power to the heater is off.
Step 5: Draw a diagram or snap a photo of the thermostat wiring.
Step 6: Use a screwdriver to detach each of the wires from the old thermostat. If any of the wire ends appear compromised, cut the end off and strip back the wire’s protective sheath to expose a half inch of fresh wire.
Step 7: Use a flat-head screwdriver to carefully pry the old thermostat up and out of its mounting bracket.
Step 8: Snap the new thermostat into place. It needs to be seated tight against the metal water tank to function properly.
Step 9: Most thermostats are pre-set to the EPA recommended temperature of 120 degrees. Water heated over 120 degrees can cause scalding. If a temperature other than 120 degrees is desired, use a flat-head screwdriver to change the temperature setting on the thermostat.
Step 10: Refer to the handmade diagram or photo of the old thermostat wiring. Attach the wires to the new thermostat accordingly, securing each wire tightly beneath each screw.
Step 11: Press the red reset button firmly to ensure it is engaged.
Step 12: Install the protective plastic safety cover and reattach the top access panel.
Step 13: Replace the lower thermostat following the same process, removing the lower access panel and proceeding as before. Lower thermostats typically have only two wires and do not have a reset button.
Once both thermostats are in place and the access panels have been re-attached, turn the power to the water heater back on.
If all goes well, you should have hot water in a couple of hours.