Machine makes loud knocking or rattling noises when the pump runs.

Safety first: Unplug the machine before opening the case.

• Check for air in system: Ensure the reservoir is full and properly seated. Run water through the hot water tap to purge air.
• Inspect pump mounts: Remove the side panel and locate the pump. Verify that the rubber mounts are intact and that mounting screws are snug but not overtightened.
• Add damping: If the pump is contacting the chassis, adjust its position or add a thin rubber pad between the pump and frame to reduce noise.
• Assess pump condition: If the pump is excessively loud and flow is weak, it may be failing and should be replaced.