Boiler makes loud banging or knocking noises when starting or stopping (kettling).

Safety: Allow the boiler to cool before working on the hydraulic circuit.

• Check system pressure and flow: Ensure pressure is correct and all radiator valves and bypass valves are open to allow adequate flow.
• Bleed air: Bleed radiators and the boiler’s air vent to remove trapped air that can cause local boiling.
• Adjust pump speed: If the pump has multiple speeds, select a higher speed to improve circulation through the Klimosz heat exchanger.
• Descale heat exchanger: For heavily scaled systems (especially in hard water areas), a chemical flush or removal and descaling of the primary heat exchanger may be required. This should be done by a professional using Klimosz-approved chemicals.