Thermador Dishwasher Error Code E12

The water used to wash your dishes contains minerals. As the water runs through the Thermador dishwasher, traces of the minerals are left behind. Overtime, this results in limescale buildup in the dishwasher’s heat pump and can cause blockages or interfere with the normal flow of water through the appliance. If you have hard water, meaning your water has especially high levels of minerals, and you don’t use softener salt, the chance and frequency of the limescale buildup occurring is higher.

Using a commercial descaling product to fix the Thermador dishwasher error code 12 is easy. Bosch is the parent company of Thermador and they make their own dishwasher descaler. Once you have the cleaning product, just follow these steps:

• Empty the dishwasher. Make sure there is not detergent in the dishwasher.
• Start the hottest and longest cycle available on your machine.
• After 30 minutes, open up the dishwasher and add one box or packet of the descaler to the bottom of the dishwasher.
• Close the dishwasher and let the cycle complete.
• Once done, run another wash cycle to rinse the machine. This time do not use any detergent or descaler.