Water heater emits a strong metallic or burning dust smell when first used after a long period off

Safety first: If the smell is accompanied by smoke, unusual noises, or error codes, turn off the appliance and call an engineer.

User checks:

• Ensure ventilation grilles around the heater are not blocked.
• Allow the heater to run for a short period under supervision; light odour may dissipate as dust burns off.

Engineer actions (if smell persists):

• Inspect the heat exchanger and burner area for accumulated dust or debris and clean as required.
• Check for signs of localised overheating or discoloured wiring.

Persistent strong odours should always be investigated by a professional.