- Appliances
- Dishwashers
E12
Bosch dishwasher E12: limescale in the heat pump
Evidence linked to this decision
View source: Bosch US dishwasher error codesRisk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
E12 means limescale buildup was detected in the heat-pump system. Let the appliance cool, isolate power and follow the model manual; most heating faults require service.
Safety first
Stop and check this first
- Stop for overheating, steam leakage, electrical smell, breaker trips or repeated heating codes. Never expose or energise a heater outside its housing.
Safe checks you can perform
- Allow a complete cool-down
- Use only the code-specific safe action
- Record heating and drying symptoms
Leave these tasks to a qualified professional
- Do not attempt this professional task: Diagnose the thermal and circulation system
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Diagnose the thermal and circulation system
What they doA technician should test circulation, enclosed heater, sensors, fan, mineral chamber and control against E-number data.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Allow a complete cool-down
Stop the programme, keep the door closed until steam and hot water settle, then isolate power at a dry supply.
Stop for overheating, steam leakage, electrical smell, breaker trips or repeated heating codes. Never expose or energise a heater outside its housing.
Evidence: Bosch US dishwasher error codes
Use only the code-specific safe action
For E12 follow the model's approved descaling instructions; for airflow codes move dishes away from the visible vent after cooling.
Stop for overheating, steam leakage, electrical smell, breaker trips or repeated heating codes. Never expose or energise a heater outside its housing.
Evidence: Bosch US dishwasher error codes
Record heating and drying symptoms
Note whether water remained cold, drying stopped or unusual noise occurred, without opening the base or side panels.
Stop for overheating, steam leakage, electrical smell, breaker trips or repeated heating codes. Never expose or energise a heater outside its housing.
Evidence: Bosch US dishwasher error codes
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Virtual technician
Does E12 still appear after these checks?
This guided flow uses the exact code and your answers to choose a test, an expected result and the next branch.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Appliances
- Brand
- Bosch
- Product type
- Dishwashers
Known code variants
- Balay dishwasher E12
- Balay E12
- Bosch dishwasher E12
- Bosch E12
- Bosch E12 error
- Bosch E12 lavavajillas
- code erreur E12 lave-vaisselle Siemens
- codice E12 Bosch
- codice E12 Siemens
- código E12 Bosch
- código E12 Siemens
- E12
- E12 Bosch dishwasher
- E12 lavavajillas Balay
- E12 Siemens dishwasher
- E:12
- erreur E12 Siemens
- Error E12 Balay
- error E12 lavavajillas Bosch
- error E12 lavavajillas Siemens
- errore E12 lavastoviglie Bosch
- errore E12 lavastoviglie Siemens
- Fehlercode E12 Siemens
- LG air purifier E12 Clean Booster
- LG PuriCare 360 E12
- LG PuriCare E12
- purificador LG E12 Clean Booster
- Siemens dishwasher E12
- Siemens E12
- Siemens Geschirrspüler Fehler E12
What it means
Bosch's official United States dishwasher table associates E12 with limescale buildup in the heat pump. This page is restricted to Bosch dishwashers: the same code on a washer, dryer or another appliance can mean something else, and the exact E-number and manual decide compatibility.
Warnings and stop conditions
- Mediumsource verified
Stop for overheating, steam leakage, electrical smell, breaker trips or repeated heating codes. Never expose or energise a heater outside its housing.
Evidence: Bosch US dishwasher error codes
Symptoms and causes
Probable causes · in order
- Heat, circulation or drying airflow is restrictedConfirmed
Scale, a blocked hydraulic path, obstructed air opening or abnormal circulation can prevent the expected temperature or drying response.
Evidence: Bosch US dishwasher error codes
- A heater, pump, fan, sensor or control circuit is faultyPossible
Several installed components share the thermal process, so the display does not identify one replaceable part.
Evidence: Bosch US dishwasher error codes
Sources and technical references
- 1
Bosch US dishwasher error codes
BSH Hausgeräte GmbH · 2026 · official_doc
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