Machine displays 'Descale' or 'Calc' and will not brew until descaling is performed.

Safety first: Follow Melitta's descaling instructions exactly. Use only approved descaling agents.

Steps:

• Prepare descaler: Fill the water tank with the recommended amount of Melitta descaling solution diluted with water.
• Start program: Navigate to the descaling menu on the display and start the descaling program.
• Follow prompts: Place a large container under the spouts and follow on-screen instructions, refilling and rinsing as required.
• Reset indicator: After successful descaling, the machine should automatically reset the descale indicator.

Regular descaling according to water hardness settings prevents heating and flow problems.