Furnace Pilot Light Keeps Going Out – What To Do?

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Inadequate ventilation might cause pilot lights to go out on occasion. However, if your pilot light goes out more frequently, it might be a cause for concern. To help you solve this problem, we have done extensive research. Here are the answers we found. 

The first thing is to turn your furnace pilot light off and wait for it to cool down. Then bend the thermocouple back into position. This usually solves the problem, and your pilot light becomes steady. Note that if the pilot opening where the flame is directed is dirty, it will become unsteady and look wavy.

To fully understand why the furnace pilot light goes out often, hang on and keep reading. We will explain the reason for this malfunction and what you can do to solve the problem easily. 

Lit burner tubes of a furnace in full fire with blue flames, Furnace Pilot Light Keeps Going Out - What To Do?

Furnace and Furnace Pilot Light [Uses and Importance]

Appliances powered by gas like water heaters and furnaces have a pilot light that produces a small flame which helps them function properly. Upon switching on this appliance, the main burner gets gas ignited by the pilot light, causing your appliance to turn on and give heat to your home.

For the furnace to be ready to turn on, a pilot light uses natural gas from the furnace to keep burning throughout the heating season. A safety device known as a thermocouple is used in conjunction with the pilot light to determine whether or not the burners have ignited.

When the furnace turns on, a valve opens and allows gas to flow into the burner, ignited by the pilot light. One of the primary functions of a furnace pilot light is that it ensures that there is a flame source available to ignite the burner(s) within the furnace when needed.

The burners are ultimately responsible for generating heat within the furnace and distributing it around the home.

Reasons Furnace Pilot Light Keep Going Out? 

Person changing an air filter on a high efficiency furnace

There are various reasons your furnace pilot light keeps going out, but here are the most likely reasons: 

The Thermocouple Has Failed

The thermocouple is the most likely reason if your pilot light fails to illuminate. The thermocouple is the copper rod that directly contacts the pilot flame. The term flame sensor is often used interchangeably, but the flame sensor mainly works as a detector as the name implies.

It is a safety feature that prevents the gas from turning on if the pilot goes out. If the thermocouple fails to shut off the gas, all gas running through the furnace can leak into your residence. With the thermocouple, you can avoid a potentially disastrous gas buildup in your home.

The Pilot Orifice is Clogged

If you can get the pilot light to turn on for a brief period, carefully examine the flame. According to the manufacturer, the pilot light should be a powerful blue cone, not a faint yellow flame. A weaker flame will not be able to engulf the thermocouple properly.

If this happens, the pilot orifice might be clogged with dirt. When cleaning out the pilot orifice, it is necessary to disassemble the pilot and then remove any dirt with a needle or compressed air. If you are hesitant to begin tampering with critical components of your furnace system, furnace repair professionals are only a phone call away to assist you.

Failed Gas Regulator

A faulty regulator in your natural gas meter outside your home will impact all gas appliances in your home, including your furnace, dryer, stove, and cooking equipment. If you experience pilot difficulties in your domestic appliances, this could be the source of the problem. Contact your utility company.

Imbalance in The Available Natural Gas

If your pilot light keeps going off, nothing may be wrong with your end. At times of high natural gas demand, the gas grid in your area may be nearing its capacity, causing temporarily reduced gas pressure. Any interruption in the delivery of gas to your furnace could be enough to cause the pilot to go out.

Inquire around your neighborhood to see if anyone else has experienced problems with their natural gas supply. If the problems continue, you should contact your utility company for assistance.

Insufficient Airflow or String Draft Affecting The Pilot

After being blown out by a draught overnight, your pilot light not re-ignite with ease the following day. This might happen on days or nights when there is a lot of wind.

A leak in the furnace's output duct could result in air being forced into the space. Keep all of your home's intake air registers open and free of obstructions to avoid the inlet's vacuum effect.

What to do When Furnace Pilot Light Keeps Going Out

Air conditioning system outside installation on of the house the air conditioner with freon

The best and simplest method to solve the problem is cleaning your pilot tube. Turn off the gas to let the unit cool down before gently cleaning it with fine-grain sandpaper to remove any remaining residue.

Turn the gas back on and re-light the pilot light after you're through, then turn the gas back off. Your light should not go out again. 

How Do I Clean The Pilot Tube On My Furnace? 

Here's how to properly clean the pilot tube on your furnace. 

Cleaning equipment

  • wire brush
  • metal file
  • pliers or wrench
  • loth or compressed air
  • wire brush
  • metal file

The process: 

Disconnect the gas to your furnace from the mains. The master valve for your furnace should be located nearby. Turn off the gas and allow a few minutes for the gas to disperse on its own.

Disconnect the pilot light and thermocouple assembly from the circuit. The pilot light and thermocouple are held in place by a small bracket, which should be visible when you open the furnace. Older models necessitate the removal of the entire assembly, whereas modern models can have the components removed one at a time as needed.

  • Use your pliers or a tool to pry the pilot light and thermocouple from their mounting bracket.
  • Use the wire brush to remove the carbon buildup and soot.
  • The metal file can be used to reach hard-to-reach regions and to remove buildup.
  • Dust should be removed using a soft cloth or a burst of compressed air.
  • Remove the assembly from the bracket and replace both components in the bracket.
  • Check the pilot light's operation.

If the furnace still won't light after turning on the gas supply, or if you smell gas leaking out, turn off the gas supply and call an HVAC technician. 

How Do You Fix a Furnace Thermocouple?

Air conditioner unit outside of home

A malfunctioning thermocouple might be why your furnace pilot light keeps going out. Always turn off the gas supply and power source prior to working on the furnace. Here is how to fix it. 

Remove The Access Cover From Its Position 

Remove the lid that allows you to access the furnace. It is necessary to wait at least 30 minutes for the thermocouple to cool completely before starting if the furnace has been running for some time.

Remove The Old Thermocouple

Remove the thermocouple end fitting from the gas control valve by unscrewing the nut on the thermocouple end fitting with an open-end wrench. Remove the thermocouple from the standing pilot burner assembly. A bracket is fastened with a nut at the bottom or two nuts, one below and above the bracket.

Find this nut and remove the thermocouple. First, loosen the nut(s) attached to the thermocouple's other end to remove the thermocouple. Removing the single burner that houses the pilot component with relative simplicity is often possible. 

Replace The Old Thermocouple With a New One

The new thermocouple's lead should be straightened and shaped to look like the previous thermocouple. It does not necessarily need to be exact, but it should have the same shape. Tighten the nut(s) securing the thermocouple to the pilot burner assembly bracket. Take care not to overtighten the screws.

Gas and Electricity Should Be Turned On

Switch on the pilot light, carefully following the directions for relighting the pilot light. Position the thermocouple to approximately half-inch as it extends into the pilot's flame.

Replace the furnace access cover and check the furnace's performance by adjusting the thermostat settings to ensure that the furnace turns on and off properly. 

Can You Bypass Thermocouple [In a Furnace]?

Thermocouple in heater

If you wish to bypass the thermocouple, you must do away with the spring mechanism. With a screwdriver, you can dislodge the spring mechanism and then remove the valve, which will solve your issue. Remove the spring from the frame and toss it away.

Replace the valve case and double-check that everything is aligned correctly to prevent propane from leaking. 

To Wrap Up

A furnace is an essential appliance since it helps keep your home at the right temperature. It can develop malfunctions from time to time. When the cost of repairs exceeds the cost of a new furnace, you should replace your furnace.

If you liked reading this post, you might want to check out our other posts about furnaces: 

How Much Space to Leave Around a Furnace

No Power to Furnace - What to do? 

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