To troubleshoot problems with a gas furnace's pilot light, it is important to check the pilot light mechanism and flame as well as the gas supply and the condition of important parts, such as the thermocouple. This covers all the elements potentially related to this type of malfunction.
To make sure the pilot light is functioning correctly, its tip needs to be kept free from residue and corrosion that may stop the gas from exiting. The tip should be cleaned regularly with a toothbrush to ensure unrestricted gas flow. The flame also needs to be adjusted so that it can properly ignite the burners in the heater. Sometimes, the lever that adjusts the pilot light flame has been inadvertently moved and needs to be readjusted.
The problem with lack of ignition of the heating mechanism is sometimes not directly connected to the function of the pilot light itself but to related elements. There may not be enough gas to keep the pilot light functioning correctly. When a gas tank is near empty, the pressure decreases, and the pilot light may not stay lit. An important accompanying piece involved in igniting the heater is called the thermocouple. It monitors the heat of the pilot flame and only opens the gas lines to the main burners when the pilot light flame is strong enough. If the thermocouple is not working properly, the burner gas lines remain.