Boiler frequently loses pressure; pressure gauge drops below the minimum and the boiler shuts down.

Safety first: Allow the system to cool before repressurizing. Hot water under pressure can cause scalding.

• Inspect for visible leaks: Check around the boiler, radiators, valves, and pipe joints for signs of water, staining, or corrosion.
• Check pressure relief discharge: Locate the PRV discharge pipe (usually outside). If it is dripping or wet, the PRV may be passing water due to overpressure or debris.
• Repressurize system: Use the filling loop to slowly raise system pressure to the recommended cold value (typically 1.0–1.5 bar). Close the valves securely afterward.
• Monitor pressure: If pressure drops again without visible leaks, the expansion vessel may be flat or failed and should be checked by a technician.