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Why Is the Pilot Light Failing in My Gas Furnace?

Repairing Pilot Light

Anyone in Chesterfield, MO, with an older furnace knows one of the challenges is the pilot light ignition. While you likely don’t think about it when it’s working properly, it comes into sharp focus when it goes out. Here’s why the pilot light in your gas furnace might fail to ignite:

Strong Wind or Draft

A strong wind is one of the most common causes for a pilot light going out. When too much wind moves across the exhaust or air intake vent, it can choke out the flame. This is also one of the easiest issues to fix; homeowners can usually resolve it by simply relighting the pilot.

Malfunctioning Thermocouple

The thermocouple is a temperature sensor inside your furnace to ensure that the pilot light is burning before releasing gas. To get the pilot lit, there’s a bypass to allow the gas to the pilot to flow while you’re lighting it. If the thermocouple isn’t sensing the flame, it’ll shut off the gas to the pilot.

There are two common issues with the thermocouple that will cause it to not sense a lit pilot. One is buildup on the thermocouple, and the other is simply a faulty thermocouple. A service technician will clean and check the thermocouple during routine furnace maintenance.

Dirty Pilot Orifice

Another area that can become problematic when dirty is the pilot orifice, which gas flows through for the pilot. This happens because of normal wear and byproducts of burning fuel, which necessitates routine cleaning.

Faulty Gas Valve or Regulator

Gas must flow through a valve and regulator before coming into the burn chamber at either the pilot or burner. The valve can become stuck as it ages and may need replacing. Further, the regulator controls the gas pressure and can prevent enough gas to fuel the pilot when malfunctioning.

If you still have a pilot light, chances are you’re working with an outdated furnace. Call to schedule a consultation with one of our furnace replacement experts at Fresh Air Heating & Cooling.

Image provided by iStock

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