Boiler makes gurgling or bubbling sounds inside the unit or in nearby piping.

Safety first: Let the system cool before bleeding air. Hot water and steam can cause burns.

• Check system pressure: Ensure pressure is adequate (typically 12–20 psi cold). Low pressure can allow air pockets.
• Bleed air vents: Open manual air vents on radiators and high points. Check automatic air vents near the Laars boiler for leaks or blockages.
• Verify pump location and flow: Pumps should generally pump away from the expansion tank connection to help remove air; incorrect piping may require professional correction.

When to call a professional: Persistent gurgling may indicate design issues or microboiling in the heat exchanger that need expert attention.