1. Faulty Pilot Light: If the thermocouple is new, the issue might be with the pilot light. Ensure the pilot light is properly lit and not flickering or unstable.
2. Incomplete Combustion: Insufficient airflow to the burner assembly can lead to incomplete combustion, causing the furnace to shut off. Check for any blockages or obstructions that might be preventing proper airflow, particularly around the air inlet and outlet.
3. Gas Pressure: Low or inconsistent gas pressure can affect the functionality of the furnace. Check the gas line for any kinks or leaks, and if needed, contact your gas supplier to evaluate the gas pressure.
4. Dirty Flame Sensor: A dirty flame sensor can prevent the furnace from detecting a flame and cause the unit to shut off as a safety precaution. Locate and clean the flame sensor according to the manufacturer's instructions.
5. Air Pressure Switch: A malfunctioning air pressure switch can affect the furnace's air circulation. Check the air pressure switch for proper functioning and make sure the tube connected to it is clear and not obstructed.
6. Faulty Control Board: If all other components seem to be functioning properly, the issue might be with the control board or thermostat. Consider consulting with a professional HVAC technician for further diagnosis.
7. Blocked Vents or Air Return: Blocked vents or obstructed airflow from the return vent can cause the furnace to overheat and shut off. Ensure all vents and air returns are clear and not covered with furniture, clothing, or other obstructions.
