Water heater is making loud banging or knocking noises when running.

Safety first: No immediate internal work required; listen and observe first.

Steps:

• Secure piping: Check that hot and cold pipes near the Marey heater are firmly strapped and not banging against walls or studs.
• Install water hammer arrestors: If banging occurs when fixtures close, have water hammer arrestors installed near quick-closing valves.
• Descale heat exchanger: Boiling or kettling sounds often indicate scale buildup. Perform a descaling flush on the heat exchanger.
• Check mounting: Ensure the heater is securely mounted to the wall and not vibrating excessively.

When to call a technician: If noises persist after descaling and securing piping, or if you suspect internal damage.