Why Won’t My Furnace Pilot Light Stay Lit?

Posted On: November 13, 2017

Gas furnaces are equipped with a small gas flame called a pilot light, used to ignite the gas released from the main burner. In older furnaces, there is a standing pilot light where the flame is lit at all times. More modern appliances utilize electronic ignition, and the flame on the pilot light is only lit once the furnace calls for heat. Routine annual furnace inspection and maintenance can help prevent issues with your pilot light and keep your heating system functioning at peak performance, but there are a number of circumstances that can prevent the pilot flame from lighting.

Reasons Why Your Pilot Light Won’t Remain Lit

Faulty Thermocouple

The thermocouple is a device that comes in direct contact with the pilot flame and senses if it is hot enough for the fuel to ignite to the burner. If everything is functioning properly, the thermocouple allows the gas to flow freely, but if it detects a lack of heat from a weak or absent pilot flame, it stops the flow, preventing a potentially disastrous buildup of gas.

There are a number of reasons why the thermocouple may be malfunctioning:

  • It’s broken or burned out
  • It’s dirty
  • It’s misaligned

Weak Flame

The color of your pilot light flame should be a steady bright blue, while a yellow flame is a sign that something is preventing the consistent, efficient flow of fuel. If this should occur your furnace will automatically shut off the gas valve, causing the pilot light to go out.

Buildup of Dirt

Over time dirt, dust, or debris can accumulate on or around the pilot light, which blocks the flow of gas and prevents the pilot flame from lighting or remaining lit.

Faulty Ignition Switch

In furnaces with an automatic ignition, there may be an issue with the ignition switch. You can test this by turning off the thermostat at the breaker box and waiting several minutes before turning it back on. This may solve the issue as the unit resets itself, but if it still fails to light, seek professional assistance.

Draft or Wind 

One of the most common reasons for a pilot light to go out is the presence of a strong draft, which may creep in to your home during exceptionally windy or stormy weather.

Inadequate Flame Height

Your pilot flame may simply be set too low, making it unable to reach the thermocouple. The weak flame may also be caused by an obstruction in the pilot tube, preventing the flow of gas.

Choose Top Notch for Furnace Repair & Maintenance in Lenexa, KS & Kansas City, MO

The pilot light on your gas furnace plays a vital role in the operation and safety of this fuel burning appliance. If you find yourself without heat due to a malfunctioning pilot light or any other furnace issues, call the experts at Top Notch Heating, Cooling & Plumbing for fast, efficient service. One of our highly trained, experienced technicians will quickly determine the cause of the breakdown, and provide expert repair to restore heat to your Kansas City home.

Contact us today to schedule an appointment or for any other HVAC questions or concerns. 

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