Boiler leaking water from underneath the casing or from pipe connections.

Safety: Isolate electrical power immediately if water is leaking inside the boiler. Risk of electric shock and component damage.

• Turn off water supply: Close the cold water inlet and, if possible, isolate the heating flow and return valves under the boiler.
• Identify leak source (visual): Remove the front cover and carefully inspect for signs of water trails, staining, or active drips. Pay attention to the Thermona plate heat exchanger, pump unions, and automatic air vent.
• Tighten fittings: Gently tighten any accessible compression nuts that are visibly leaking. Do not overtighten plastic components.
• Dry and monitor: Dry the area and restore water briefly to confirm if the leak persists and from where.
• Component replacement (engineer level): Replace leaking components such as the plate heat exchanger, automatic air vent, or corroded pipe sections. Refill, vent, and test the system for further leaks.