Soot buildup above the fire chamber in your Mr. Heater can indicate incomplete combustion. This may occur due to insufficient airflow, improper fuel-to-air ratio, or a dirty burner. Make sure the unit is well-ventilated and that there's no obstruction to airflow. Regular maintenance, including cleaning the burner and ensuring the appliance is in good condition, can also help prevent soot accumulation. If the issue persists, it's essential to discontinue use and have the heater inspected by a qualified technician.
Asked Oct 1, 2026 9:05 PM