Types of Gas Furnace Ignition and How to Fix Them

Our expert gas furnace repair technicians can fix all kinds of equipment.

Types of Gas Furnace Ignition and How to Fix ThemGas furnace won’t light? The first step to fixing this problem is figuring out which kind of furnace ignition technology you have, standing pilot light or electronic ignition. Learn more about these two types of furnace ignition technology and how the gas furnace repair specialists at General Heating & Air Conditioning fix them.

Standing Pilot Light

The traditional ignition mechanism for a gas furnace is a standing pilot light. Standing pilot lights burn constantly, providing a flame that can be used to light the main burners whenever the furnace thermostat drops below your desired temperature setting. This technology is found in many older models as well as in the less efficient end of the new furnace market. Because standing pilot lights are always on, they naturally use more fuel than other ignition methods. This fuel is never converted to heat, which means that standing pilot light furnaces typically don’t have AFUE ratings over 80.

Electronic Ignition

Newer, more efficient furnaces utilize electronic ignition to eliminate the waste and unreliability of a standing pilot light. There are two types of electronic ignition, intermittent pilot and hot surface ignition.

An intermittent pilot system generates a high voltage electrical spark whenever the thermostat calls for heat. This spark ignites a gas pilot, which then works just like the standing pilot light did. A hot surface ignition system uses a resistance heating element similar to a light bulb filament, rather than a spark, to trigger the ignition of the main burners.

Gas Furnace Repair Strategies

If your furnace burners are not igniting, the first thing we will do is ensure that gas is flowing to your furnace by inspecting the gas valves. We will also check all the electrical connections as well as the thermostat sensors and mechanisms.

If your standing pilot light is out, we can send a gas furnace repair tech to relight it for you. It is important to have a professional handle this task because they will ensure that the flame is properly adjusted—neither too strong nor too weak. A weak flame will not heat the thermocouple sufficiently, in which case no gas will flow to the main burners. If your electronic ignition mechanism is not working, we may need to replace it.

Another possibility is that your thermocouple may need to be replaced. This would be the case if your ignition system is working properly but the main burners never come on.

For an expert diagnosis and repair of your gas furnace, regardless of its age or ignition type, please contact General Heating & Air Conditioning now.