Boiler leaking water from underneath the casing

Safety: Isolate electrical power immediately if water is leaking near electrical components. Do not remove the sealed combustion cover yourself.

• Identify source area: Place a dry cloth or tray under the boiler and observe where water drips from (left, right, centre) to help the engineer locate the leak.
• Check pressure relief discharge: Look outside for the copper pressure relief valve (PRV) pipe. If water is dripping constantly, the PRV may be passing due to high pressure or debris.
• Check system pressure: If pressure is above 2.5–3.0 bar, reduce it by bleeding a radiator into a container until around 1.2–1.5 bar cold.
• Do not open casing: Internal leaks from the primary heat exchanger, pump, or air vent must be repaired by a qualified engineer.
• Engineer tasks:
  • Inspect and replace leaking automatic air vent or seals.
  • Test and replace a faulty pressure relief valve and investigate cause of overpressure.
  • Assess corrosion on the primary heat exchanger and replace if necessary.

Prolonged leaking can damage the PCB and other components; arrange repair promptly.