Here are five reasons why your furnace pilot light isn't working.
1. Your furnace pilot light is out due to a lack of airflow. The furnace pilot flame requires a steady source of airflow to keep the gas flowing. If there is not enough ventilation for this specific purpose, it can create issues when starting the furnace.
2. Your furnace pilot light went out due to a lack of fuel. If your furnace is starved for fuel, it can cause the furnace pilot light to go out unexpectedly and create other furnace problems that may not be as easily fixed as relighting a furnace pilot light.
3. The furnace pilot assembly itself is faulty and therefore unable to keep the gas flowing properly.
4. There might be debris blocking the airflow path around or under your furnace, preventing it from being ignited.
5. Finally, if you have an older home and have never replaced your furnace's thermocouple—a critical part of the furnace that regulates temperature—your furnace may not have enough power to light the pilot light as it should.