Machine displays ALARM 12; hot water tap temperature or flow is abnormal, or hot water function is disabled.

Safety first: Turn OFF and unplug the machine. Allow the hot water circuit to cool before disassembly; hot water can cause burns.

Steps to address ALARM 12:

• Check for blockages: Remove the hot water spout tip and clean any scale or debris. Run water (if possible) to see if flow improves.
• Inspect hot water solenoid: Locate the solenoid controlling the hot water outlet. Listen for a click when the hot water button is pressed. If it energizes but no water flows, the valve may be blocked.
• Clean or replace solenoid: Isolate water, depressurize, and remove the valve. Clean internal parts and screens. Replace the valve if the coil is burned or the body is damaged.
• Check mixing valve (if equipped): Many La Marzocco machines mix steam boiler water with cold water. Inspect the mixing valve for scale buildup and restricted movement. Descale or replace as needed.
• Verify temperature sensor: If the machine uses a dedicated hot water temperature sensor, inspect wiring and test resistance. Replace if faulty.
• If ALARM 12 persists: The control logic for hot water may be compromised; consult an authorized technician.