Furnace makes loud banging or knocking noises when starting or stopping

Safety: Be cautious around hot pipes and radiators.

Steps:

• 1. Bleed air: Remove air from radiators and high points in the system.
• 2. Lower flow temperature: Reduce heating temperature to minimize expansion stress.
• 3. Check pipe supports: Inspect accessible pipes and add or adjust clips to prevent movement.
• 4. Technician actions: Fit anti-water-hammer devices if needed and check pump speed and bypass valve settings.