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Furnace Pilot Light Won’t Stay Lit – Now What?

Originally published January 2014, updated November 2016

When winter hits Newnan, Georgia, you want to be sure your furnace will keep you warm. If the furnace’s pilot light won’t stay on, the furnace won’t work. Common causes include the thermocouple and pilot tube. The thermocouple detects the pilot light via sensors. A faulty thermocouple may arbitrarily determine that the light is off when you want it on and vice versa. It just may be that the thermocouple is bent. If so, it will not face the pilot light. Sometimes, this causes the pilot light to stay on for only a few seconds. You can try bending the thermocouple back into position. Be sure to inspect the thermocouple carefully. It may be that it is dirty and needs a cleaning. It can easily be cleaned off with a fine grain sandpaper.

A dirty pilot tube can also prevent the pilot from staying lit. If the pilot tube is dirty, let the furnace cool down and turn off the gas. Once cooled, the pilot tube can easily be cleaned.

How to Light Your Furnace

If you have an older model furnace with a standing pilot light, you can follow this basic procedure to relight the pilot flame.

  • Make sure the thermostat is in heat mode.
  • Locate the pilot valve. It’s a box-shaped device and is typically located near the gas burners.
  • Turn the valve knob to the off position. Wait several minutes for any residual gas to clear away
  • Get your match ready. If the pilot is hard to reach, you may have to use a long fireplace match. Butane grill lighters work well also.
  • Once the pilot stays lit, turn the pilot valve to the on position. This will keep the flow of gas and ignite the burners.

When to Replace Your Furnace

There are often telltale signs to alert you that it may be time to replace your furnace. These include high energy bills, uneven heating, frequent on/off cycling, humidity problems, noise, excessive dust or soot, and the need for frequent repairs. If your furnace is more than 15 years old, it may be a good idea to consider a replacement. Today’s models have a lifespan of 20 to 30 years and are more efficient than older models. According to the EPA, the new Energy Star furnaces can save about $100 a year in energy costs.

HVAC Services and Products at Merrell & Associates

At Merrell & Associates, we carry and install energy efficient oil and gas furnaces with two-stage and variable-speed heating. Our top brands are engineered with the most advanced technology and offer optimal indoor comfort. Be sure to call us at 770-872-4171 if you’re in the market for a new furnace.