Boiler shows code 6, burner off, pump running, boiler cooling down after demand

Information: Code 6 typically indicates a cool-down phase and is not a fault. The pump runs to remove residual heat from the heat exchanger.

• Observe system: Radiators may continue to warm slightly after the burner stops. This is normal.
• Check for overheating: If radiators are excessively hot and the boiler frequently reaches maximum temperature, ask an engineer to check flow rates and system balance.
• Bleed radiators: Air in the system can reduce circulation and cause higher boiler temperatures. Bleed radiators and re-pressurise the system.
• Engineer review: If code 6 persists for very long periods or the boiler overheats, a technician should inspect the pump performance, system resistance, and NTC sensors.