Machine shows AL3 and shuts down heating; may have overheated or run dry.

Safety first: Turn OFF, unplug, and let the machine cool completely. Do not attempt to reset an overheated boiler while it is hot.

• Check water supply: Ensure the water tank is full, correctly seated, and that the tank inlet filter is not blocked. On plumbed-in models, verify the water shutoff valve is open.
• Prime the system: With the machine cool and powered ON, run the brew pump (open the group) for 20–30 seconds to ensure water flows steadily from the group head. If no water flows, stop immediately and investigate the pump and intake.
• Inspect brew boiler safety devices: Remove the top cover and locate the brew boiler. Many Lelit models have a manual-reset thermostat or thermal cutout on the boiler. Look for a small round device with a red button; press gently to reset if present.
• Check for scale: If the machine has not been descaled regularly, heavy limescale can cause localized overheating. Plan a controlled descaling using a manufacturer-approved descaler, following Lelit’s instructions.
• Observe heating behavior: After reset and priming, power ON and monitor. If the boiler overheats rapidly or AL3 returns, the brew boiler thermostat or control board triac may be faulty and should be tested or replaced by a technician.