E12

Limescale Build-Up (Descale Required)

Description

Limescale has built up in the heat pump, usually in hard-water areas, reducing heating efficiency.

Appliance Error Codes Details

Error Code
E12
Error Name
Limescale Build-Up (Descale Required)
Appliance Type
dishwasher
Brand
Bosch
Severity
low

Possible Causes

  • Water circulation problems
  • Drain system blockage
  • Heating element failure
  • Control system malfunction
  • Door latch or seal issues

Step-by-Step Solution

  1. 1. Clean filters and spray arms
  2. 2. Check water supply temperature
  3. 3. Inspect drain hose and connections
  4. 4. Verify proper loading and detergent
  5. 5. Test cycle selection and settings

Additional Troubleshooting

1. Run a descaling cycle with a dishwasher descaler. 2. Refill the water-softener salt and set the correct hardness level. 3. Severe scale may need two or three descaling cycles. 4. Use rinse aid and salt regularly to prevent future build-up.

When to Call Service

  • Pump motor replacement should be done professionally
  • Control system diagnostics require specialized equipment
  • Plumbing connections may need professional installation

Prevention Tips

  • Clean filters weekly
  • Scrape dishes before loading
  • Use proper detergent amount
  • Run hot water before starting cycle
  • Check drain hose monthly

Was this helpful?

Loading...

Send Feedback

Found an error or have a suggestion? We respond within 48 hours.

Fact-checking completed

Verified by: Pavel Volkov
Created:
Last updated:
Information verified against official sources

Official Sources

Official Manufacturer Service Manuals

Service manuals and technical documentation from appliance manufacturers

Original equipment manufacturers official documentation

Industry Standards Organizations

International standards for electrical appliances and error codes

International Electrotechnical Commission standards