Gurgling or rushing water sounds in pipes and radiators when furnace runs

Safety: Be cautious of hot water when bleeding radiators.

Steps:

• Bleed radiators: Starting with upper floors, open bleed valves until water flows without air. Close valves and top up system pressure as needed.
• Check automatic air vents: Ensure caps on auto vents near the Buderus furnace are slightly open to allow air release.
• Maintain pressure: Keep system pressure at the recommended level to prevent air ingress.

Persistent air problems may indicate a leak or failing air separator that should be addressed by a technician.