Machine displays ALARM 6; steam boiler overheats or temperature is reported as excessively high, and heating is disabled.

Safety first: Turn OFF and unplug the machine immediately. Do not attempt to release pressure by loosening fittings; use the hot water tap and steam wand only after the boiler has cooled to a safe level.

Corrective steps:

• Cool and depressurize: Allow the machine to cool. Open the hot water tap and steam wand to relieve residual pressure once temperature is safe.
• Inspect steam boiler SSR/contactor: Access the electrical compartment and locate the SSR or contactor controlling the steam boiler element. Look for burn marks or melted housing.
• Test SSR operation: With the machine unplugged, disconnect one leg of the steam heating element and check continuity across the SSR output. If it is closed when it should be open, the SSR is stuck and must be replaced.
• Check steam temperature probe: Inspect wiring and connector. Test resistance at room temperature and compare to spec. Replace if readings are out of range.
• Evaluate scale buildup: If the machine has not been descaled regularly, internal scale may cause overheating. Plan a professional descaling and inspection of the steam boiler.
• Replace failed parts: Install a new La Marzocco steam boiler SSR/contactor or temperature probe as needed. Ensure proper heat sinking and wiring for SSRs.
• If ALARM 6 persists: The control board may be misregulating steam temperature. Seek professional service for board diagnostics.