Boiler or nearby piping vibrates excessively and produces humming or rumbling noises

Safety first: Use caution around moving pump parts and hot surfaces.

• Bleed system: Remove air from radiators, manifolds, and air separators to reduce noise.
• Check pump speed: If using a multi-speed circulator, try reducing speed slightly to eliminate cavitation while maintaining adequate flow.
• Tighten mounts: Inspect pump flanges, brackets, and boiler mounting hardware. Tighten any loose fasteners.
• Verify piping support: Ensure long runs of copper or PEX are properly supported to prevent resonance.

Professional help: If vibration persists, a technician should check pump sizing and system hydraulics.