What E12 Means
Thermador documents E12 as limescale build-up in the heat pump.
Common Causes of E12
- Hard water mineral deposits accumulating in the heat pump over time
- Infrequent or skipped descaling maintenance
🔧 One Safe Check You Can Try
Run a dishwasher-safe descaling product through a cycle, and add water-softening salt if your model uses it.
⚠ Why You Shouldn't Go Further Than That
- If descaling doesn't clear it, the heat pump itself may need inspection, which is a technician task.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.