Water heater makes loud banging or knocking noises when starting or stopping

Safety: Sudden banging can indicate stress on pipework. Inspect carefully for leaks.

• 1. Check water pressure: If a pressure gauge is fitted on the cold supply, ensure it is within recommended limits. Consider a pressure-reducing valve if pressure is high.
• 2. Secure pipework: Inspect visible hot and cold pipes near the Beretta heater. Add clips or brackets where pipes can move and hit walls or other pipes.
• 3. Descale heat exchanger (technician): Limescale can cause localized boiling and knocking. A professional should descale the primary and/or secondary heat exchanger.
• 4. Install water hammer arrestors: If banging occurs when taps close, a plumber can fit water hammer arrestors on the supply lines.