E12
Gaggenau
Limescale Build-Up in Heater / Heat Exchanger
Dishwasher shows E12, often after long use in hard water areas; poor heating and long cycles.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Heavy scale on heater surfaces, clogged heat exchanger channels, incorrect water softener setting, use of non-softened water
How to Fix / Troubleshooting
Safety: Turn off power and water supply.
Steps:
- Run descaling program: If available, run a machine care or descaling cycle using a dishwasher descaler approved by Gaggenau.
- Check water softener setting: Adjust the built-in water softener to match your local water hardness (see user manual). Refill the salt reservoir with dishwasher salt.
- Inspect heat exchanger: Remove the side panel to view the heat exchanger/water matrix. Heavy white deposits indicate scale.
- Manual descaling: In severe cases, remove the heat exchanger or heater assembly and soak in a descaling solution compatible with stainless steel and plastics. Rinse thoroughly.
- Replace components: If scale cannot be removed or components are damaged, replace the heat exchanger or heater assembly.
Prevention: Always use dishwasher salt and set the softener correctly in hard water regions.
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Repair Difficulty
Medium
3/5
Required Part
Heat Exchanger / Water Matrix
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