The expected service life of your furnace is directly related to how certain components are operated. One of these is the pilot light, which ignites the main burner when your thermostat signals for heat. All pilot lights incorporate a safety device, called a thermocouple, to continuously sense the heat of the pilot flame. If the pilot light is out or not producing a properly adjusted flame, the thermocouple shuts off gas to the furnace burner.
Unlike the main burner, the pilot light burns 24/7. Therefore, it’s subject to soot and combustion byproduct accumulation, which may affect the pilot flame or the performance of the thermocouple.
Here’s how your HVAC professional will perform your routine pilot light check , which should be part of your regular annual maintenance visit:
- After turning off the gas supply to your furnace and waiting five minutes for residual gas fumes to clear, your technician will remove the bracket securing the thermocouple/pilot light assembly. The gas tube is then unscrewed from the assembly and the pilot light and thermocouple are removed from the assembly.
- Soot residue around the tip of the pilot is removed with a wire brush or metal file. The surface of the thermocouple is also cleaned the same way. Afterwards, dust and other particles are blown out of the pilot light with compressed air.
- After the pilot light and thermocouple are reinstalled, the gas tubes are connected and the furnace gas valve is turned on. Your technician will ensure that all connections are secure and that there are no gas leaks before re-lighting the pilot.
- After observing the pilot, your technician will verify if the flame is bright blue (not yellow) and long enough to contact approximately a 1/2 inch of the thermocouple. If necessary, flame length will be adjusted by rotating the pilot adjustment screw, which is usually located on the body of the gas valve.
For professional pilot light service and annual tune-ups to extend the life of your furnace, contact Marsh Heating & Air Conditioning in the Twin Cities Metro area.
Our goal is to help educate our customers in Minneapolis-St. Paul, Minnesota about energy and home comfort issues (specific to HVAC systems). For more information about furnaces and other HVAC topics, download our free Home Comfort Resource guide.
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