Boiler leaking water from underneath the casing or from internal components.

Safety: Isolate electrical power and, if leak is significant, close the isolation valves and allow the boiler to cool. Water near live parts is dangerous.

• Identify leak source: Remove the front cover and use a torch to trace the highest visible point of moisture. Check around the pump, air vent, heat exchanger, and pipe unions.
• Tighten fittings: Gently tighten any accessible compression or union fittings that are weeping. Do not overtighten plastic components.
• Replace faulty components: If the automatic air vent is dripping from the top, replace it. If the pump body or shaft seal is leaking, replace the pump assembly.
• Heat exchanger leaks: If water is seeping from the primary heat exchanger body or welds, the exchanger must be replaced; this is typically a technician job.
• Re-pressurise and test: After repairs, top up system pressure, bleed air, and run the boiler while monitoring for further leaks.