Common Furnace Pilot Light Issues & What to Do About Them

July 15, 2024

4 Common Furnace Pilot Light Issues, Causes, and Solutions 

In the Bay Area, a gas furnace can last longer than a heat pump because it only runs for part of the year, with a service life that can exceed 15 to 20 years. ENERGY STAR models with an Annual Fuel Utilization Efficiency (AFUE) rating of 94 to 98.5% also help reduce your energy bill and your home’s environmental impact. 

But, like any large appliance, your gas furnace can experience early wear and tear if you skip yearly maintenance. The pilot light is often the first component to show signs of trouble. Let’s explore the common causes of furnace pilot light issues and some solutions to get your furnace back into top shape.

What Is a Furnace Pilot Light?

A furnace pilot light is a small flame that ignites a gas furnace. When it operates correctly, it is a steady, thin blue flame. 

Pilot light components

  • The main gas valve controls the gas to the main burner and pilot light. 

  • The pilot control knob has an on, off, and pilot setting. In the off position, no gas flows to the pilot light. The pilot setting is used for starting the flame.

  • An internal gas valve inside the pilot light mechanism controls the flow of gas to the pilot light flame.  

  • The thermocouple controls the gas valve. 

  • The air intake valve feeds oxygen to the flame.

4 Common Pilot Light Issues

There are four common furnace pilot light issues. They range from a lack of general cleanliness to faulty and damaged components. Let's get into it.

1. The pilot light won’t stay lit

The main issues that keep a pilot light from staying lit are a dirty or damaged thermocouple, a clogged or damaged gas tube, or a faulty pilot control knob. 

If the thermocouple is damaged or dirty, it won't keep the valve open. When there's a clog from soot and carbon build-up or a damaged and kinked gas tube, the flame won't get enough gas flow to remain lit. A faulty pilot control knob will decrease or halt the flow of gas and cause the pilot light to go out.

Potential solutions

Have the thermocouple, valve, and tubing cleaned. Replace any kinked or damaged lines, and service the pilot control knob. 

2. The pilot light keeps going out

When your pilot light frequently goes out, there could be a few culprits:

  • Improper venting can starve the flame of needed oxygen and cause it to go out. 

  • Gusts of air from drafts near your furnace can blow the flame out. 

  • A faulty thermocouple can fail to keep the internal gas valve open. 

  • Condensation buildup can drip on the pilot light and extinguish it.

Potential solutions

If it’s an airflow issue, check your vents for damage and repair or replace them. You should also replace the air filter, clean the air intake valve, and keep the area around the furnace clear to keep dust from accumulating. 

If you have a drafty space, locate the source of the air infiltration and either try to direct it away from the furnace or repair the draft.

If your thermocouple is faulty, have it serviced or replaced.

Condensation build-up is a sign you have a bigger issue in your home. The Concord area is nestled in a low-humidity region, but even in the cooler winters, when we see more rain, your home should not experience so much regular condensation that it affects your pilot light. The helpful technicians at Service Champions can troubleshoot your furnace and the various systems in your home, identify potential problems, and offer actionable solutions.

3. The pilot light flame is weak or flickering

There are two main causes for a weak or flickering flame — dirt and airflow.

Dirt in the tube can obstruct gas flow and cause the flame to flicker or weaken. Poor airflow starves the flame of oxygen, causing it to sputter and flicker as it tries to stay alive. 

Potential solutions

Regular furnace maintenance and cleaning will eliminate both of these issues. To resolve the gas flow issue, schedule a service to clean the dirt out of the tube. To increase the air to the pilot light, have your HVAC pro clean the air intake valve. 

4. The pilot light flame is orange or yellow

A dirty or clogged air intake valve limits airflow, causing an orange or yellow flame. An orange or yellow flame produces carbon monoxide, a dangerous gas if it builds up in your home. It's also not hot enough to heat the thermocouple, so your gas valve won't fully open.

Potential solutions

To restore airflow to the pilot light, have the air intake valve cleaned regularly.

How To Relight Your Furnace Pilot

While it’s generally safe to relight the pilot yourself if you take the proper precautions, don’t try to restart the pilot if you smell gas. Turn off the main gas valve and the power to the furnace before attempting any maintenance. Or better still, contact the pros at Service Champions — our knowledgeable technicians can light your pilot, inspect your furnace for any issues, and tackle any necessary repairs. 

These are the general steps for relighting a pilot light. Refer to your owner’s manual for instructions for your particular furnace.

  1. Allow three to five minutes for the residual gas to clear the furnace housing. 

  2. Remove the covering or panel to access the pilot. 

  3. Locate the control knob and turn it to the pilot setting.

  4. Press down on the red starter button to ignite the flame. 

  5. Keep the button pressed for 30 seconds to allow the thermocouple to heat up.

  6. After 30 seconds, turn the knob to the on or open position. Monitor the flame for a minute or two to ensure it doesn’t extinguish.

  7. Replace the access panel.

Regular Maintenance Helps Prevent Pilot Light Issues

Your gas furnace can last 10 to 15 years with the proper upkeep. Change the air filter at least twice a year, keep the furnace clean and dust-free, and stay up-to-date with season preventive maintenance. Contact us to schedule maintenance or furnace repair in Martinez, CA, (or the surrounding Concord area) with one of our friendly and knowledgeable furnace technicians.

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