Water heater makes loud banging or knocking noises when heating

Safety: Noise itself is not usually dangerous but may indicate stress on pipework.

• Check pressure: Measure incoming cold water pressure. Install or adjust a pressure-reducing valve if pressure exceeds Dimplex recommendations.
• Secure pipework: Ensure pipes to and from the heater are properly clipped and supported to reduce movement.
• Install water hammer arrestor: Fit an arrestor near quick-closing valves (e.g., solenoid valves, mixer taps) if hammer persists.
• Descale: If in a hard water area, descale the heater to reduce kettle-like noises from scale.