In older furnaces, the pilot light plays a critical role in the initial phase of the gas ignition process. A well-maintained and reliable pilot ensures that the heating cycle will continue to perform safely while keeping the indoor environment comfortable and warm.

If you discover the pilot light in your furnace is faulty, it is important to contact a licensed HVAC contractor. In a situation where the smell of gas is present, the furnace should be shut down immediately until the issue is identified and repaired.

Common Pilot Light Problems

The furnace pilot light is a small, regulated flame that serves as the ignition point when gas flows into the furnace. Older systems use unstable standing pilot systems, but newer furnaces incorporate electronic ignition technology. A pilot light that will not stay lit is typically caused by one of the following problems:

* Defective Ignition Switch: Most modern furnaces use an electronic ignition system that creates a spark to light the pilot. Ignition issues can be exposed by turning the power off to the furnace and resetting the breakers. When the furnace is back turned on, check the ignition system to see if the spark generator is working properly and lighting the pilot. If there is no sound or an active flame, call an HVAC service provider.

* Clogged Orifice: The orifice attached to the flame tube will accumulate a variety of contaminants including dirt, grime and soot. When the tip is clogged, the flow of gas is blocked, and the pilot light may become starved for fuel. If the clog is minor, a stiff bristle brush can be used to clear the debris from the orifice. Caked on grime embedded inside the flame channel can be dissolved by soaking the tip in a degreasing solution.

* Flame Adjustment: Many furnaces have a manual pilot flame adjuster. When the flame is weak and small, the burners may not ignite, and the pilot itself may be extinguished. Incremental minor adjustments on the screw bolt will help increase the size of the flame. In most instances, this will fix the problem. When making any adjustments to the pilot, it is important to follow the manufacturer’s guidelines to establish the proper flame dimension.

* Thermocouple Malfunction: A thermocouple uses heat sensors to ensure the gas flow is turned off when the pilot is disengaged. If the thermocouple malfunctions, it may not recognize that the pilot has been activated, and the flow of gas will never reach the burners. Once the gas in the reservoir is empty, the pilot light will self-extinguish. Repositioning the thermocouple directly in the pilot’s flame path can correct the problem in some cases. However, those who are not comfortable with altering furnace mechanics should call an HVAC technician.

* Gas Leaks: Leaks in the gas line connected directly to the furnace can negatively impact performance and may cause a catastrophic failure. If the leak is significant, there may not be enough gas available to sustain the pilot. Any leak in a gas pipe is a serious safety issue and should be immediately reported to a licensed plumbing contractor and your local gas company.

Furnace Maintenance Services

Furnaces tend to run discretely in the background, so the equipment is often neglected until it malfunctions. Worn parts cause unexpected breakdowns and may lead to permanent damage. A heating failure during severe weather can be inconvenient and create health and safety issues for senior citizens and young children.

Routine maintenance will ensure that your furnace continues to operate dependably while providing sufficient capacity to keep your family warm and comfortable. On a semiannual basis, trained technicians work with hi-tech equipment and perform a variety of tests designed to improve performance and expose hidden issues.

Every HVAC maintenance agreement includes a number of critical services designed exclusively for central furnace systems.

* Test and adjust the ignition system
* Adjust the pilot flame if necessary
* Adjust the burners for optimal efficiency
* Inspect the heat exchanger for cracks and breeches
* Calibrate the blower
* Replace the furnace filter
* Clean and lubricate moving parts
* Tighten electrical connections
* Inspect the vent pipe
* Reset the thermostat if necessary
* Test the amp draw across the blower motor

Reliable Furnace Operation

Gas furnace pilot light issues may be a symptom of a more serious mechanical or electrical problem. If your furnace is more than 10 years old, a new high efficiency model may provide better comfort and cost far less to operate.