Boiler makes a high-pitched whine or grinding noise during operation

Safety: Isolate power before touching the boiler. Moving parts can start unexpectedly.

• Identify noise source: Remove the front cover and carefully listen to determine whether the noise comes from the pump (usually lower front) or the fan (upper section near flue).
• Check pump for air: Bleed the pump via its bleed screw (if fitted) to remove trapped air, which can cause noise.
• Debris check: Sometimes debris can lodge in the pump impeller. An engineer can remove the pump head and inspect/clean the impeller.
• Replace worn components: Noisy bearings in the pump or fan generally require replacement of the pump assembly or fan assembly by a professional.