1. Remove the cover from the water heater.
  2. Disconnect the water line from the heater.
  3. Remove the screws that hold the thermostat to the water heater body.
  4. Lift off the thermostat housing and remove it from the water heater body.
  5. Place a clean cloth on a work surface and wet it slightly, then wring it out until it’s damp but not sopping wet.
  6. Pour enough of the cleaning solution onto a cloth to cover both ends of one of the thermocouples (the black part). Wipe down each end of each thermocouple, then place them back on top of the water heater body, making sure they’re facing inwards so that their tips are touching (this will help keep them clean).7: Replace both thermocouples if necessary (it’s rare for them to get dirty).