Navien furnace emits a strong exhaust or burning smell near the unit or vent termination

Critical safety: If you suspect flue gas or carbon monoxide, shut off the furnace, ventilate the area, and evacuate if necessary. Install and check CO detectors. Contact a licensed technician immediately.

• Inspect vent connections: With power and gas off, check all PVC vent joints for signs of leakage (staining, soot). Re-glue or replace any suspect sections.
• Check vent termination: Ensure the exhaust termination is clear and properly installed per Navien guidelines.
• Clean heat exchanger: Have a technician inspect and clean the primary heat exchanger and burner if there is evidence of soot or incomplete combustion.
• Combustion analysis: A professional must perform a combustion test and adjust gas valve settings to ensure safe, clean burning.