Strong fuel or exhaust smell around the furnace during operation

Safety first: If you smell gas, evacuate immediately and contact your gas supplier. For oil or exhaust smells, turn off power and fuel and ventilate the area. Do not ignore combustion odors.

Steps:

• Inspect flue connections: Check all visible flue joints for gaps, corrosion, or soot marks indicating leakage. Tighten clamps and reseal with appropriate high-temperature sealant where allowed.
• Check burner mounting: Ensure the burner flange is tightly sealed to the combustion chamber with the correct gasket.
• Oil systems: Inspect oil lines, filter, and Danfoss oil pump for wet spots or drips. Tighten fittings and replace damaged copper lines.
• Call a professional: A cracked heat exchanger or improper combustion must be diagnosed with test instruments. Do not operate the furnace until inspected by a qualified technician.