How To Tell If Furnace Ignitor Is Bad? (2023 Updated)

A reliable furnace becomes essential to keeping our homes warm and comfortable as the temperatures drop. 

One crucial furnace component is the ignitor, which is responsible for initiating the combustion process that provides the necessary heat. However, like any mechanical part, the ignitor can wear out over time and require replacement. 

Recognizing the signs of a faulty ignitor can help you diagnose the issue and ensure your furnace continues to function efficiently. Ignitor problems are common in furnaces. The following three signs might indicate a bad furnace ignitor:

  • A sudden stop and start
  • The furnace will not cycle
  • Vents blowing cold air

In this guide, we will explore the key indicators that can help you determine if your furnace ignitor is going bad, helping you to take the necessary steps to restore warmth to your home.

What Does a Gas Furnace Ignitor Look Like?

The ignitor is the part that starts your furnace, and you need to know what it looks like so that you don’t screw it up.

When you remove the burner panel door, you’ll find a small device connecting the electrical wires and the furnace near the gas input.

  • Most surface igniters have a white ceramic base with a flat metal surface.
  • There are typically two metal prongs on spark ignitors that generate sparks.

You can identify a problem with an ignitor after you locate it.

How Does A Furnace Ignitor Work?

Pilot lights were used to heat the air blowing into your home with older furnaces. Every year just before the temperature dropped, you probably observed your parents bravely lighting the furnace’s pilot light.

Most furnaces today use an igniter instead of an open flame to light the pilot light. Neither your heater nor the ignitor will produce heat without it. This is a key component of your furnace system and is the most common cause of failure.

A loud “click” will likely be heard from your furnace before it blows air. Upon triggering the thermostat, the system begins to run.

As a furnace generates the heat, a spark is created, which ignites the gas attached to the heater. The flame of another type of igniter does not produce a spark.

Instead, the ignitors heat up and touch the gas surface to heat the air blowing from the furnace.

Regardless of the type of ignitor in your furnace, this chain of events lights up your heater and makes it heat up.

There is nothing to worry about. Most furnaces have ignitors that go bad from time to time. In most cases, you do not need to replace the entire furnace when replacing the ignitor.

It is typical for ignitors to last for seven years. By continuing reading, learn how to tell if your furnace is malfunctioning because of a faulty ignitor.

What Causes A Furnace Ignitor To Fail?

What Causes A Furnace Ignitor To Fail

You may experience furnace ignitor problems for a variety of reasons. The ignitor may simply be too old, for example. As a rule of thumb, most ignitors last approximately seven years.

This may mean you need a new ignitor if yours is about that old. In addition, there are other possible explanations.

Short Circuit

In general, gas furnace ignitors utilize the 120-volt electrical supply from the household circuit.

Through this electricity, the ignitor produces a spark or heats the silicon to ignite it into flames. Inflammatory may short-circuit if fluctuations occur in this optimum range.

For instance, a surge in supplies can overload a circuit breaker. Consequently, there will be no ignition due to obstruction of the electric connection.

Risk-flipping the breaker switch back once it is possible to test the situation. A professional may be required to examine your home’s wiring system and electric current if it keeps switching.

Flame Sensor Problems

Regardless of the model of your furnace, it includes an ignition sensor to prevent dangerous explosions. Furnace ignition is triggered by a flame sensor that confirms a pilot flame and sends voltage to the valve.

A gas build-up is prevented due to this process, which ensures the system does not start without fire. The thermocouple performed this function in older furnace models.

It is common for these sensors to malfunction when the furnace lacks cleanliness. Deficiencies in the gas supply are caused by a burner caked in debris, which then triggers the sensor with a false alarm. Therefore, the sensor shuts off the flame.

Clean the soot-covered rods simply by using soap and water. You might have to consider a total replacement if the damage is too extensive.

For information on buying a suitable replacement sensor, consult the user manual or the model number. Accessing the sensor is possible through the access panel.

Don’t attempt the replacement at home unless you are good at mechanics. If the sensor is not installed correctly, the situation could get worse. Ensure the job is done correctly by hiring an HVAC technician.

What Are The Symptoms Of A Bad Igniter In A Furnace?

What Are The Symptoms Of A Bad Igniter In A Furnace

Many things could be causing a furnace not to work. A number of the most common symptoms could indicate a variety of issues. A few signs can identify a faulty ignition system.

I Hear the Click, But Nothing Happens

A click you heard earlier is caused by an ignitor trying to warm up the fuel in your furnace. Nonetheless, if you hear the click but don’t notice the air coming out quickly, there could be a problem with your ignitor.

To check the condition of your furnace’s ignitor, ensure you know what to look for and how to reach it before entering the system!

Tripping the Breaker More Than Once

During our discussion, we mentioned checking the furnace breaker. It is possible, however, that you have a faulty igniter if your furnace keeps tripping the breaker when it starts blowing air.

When you trip the breaker repeatedly, your furnace and electrical system are negatively impacted.

Despite a simple fix, do not let the furnace trip the breaker more than twice due to a defective furnace ignitor. When repairing the furnace, leave the breaker off.

Starts, Then Stop, Then Starts Again

Starts, Then Stop, Then Starts Again

If your furnace turns on and off frequently, your ignitor may be to blame. In an emergency, an ignitor isn’t able to hold a charge long enough to heat the furnace air.

You may also have a safety feature that forces your furnace to wait at least 60 seconds before it begins working again.

Furnace failure results from repeated on-and-off operations. To prevent a more severe furnace problem, look for the situation when you see it cycling on and off.

The Furnace Suddenly Stops Blowing

Furnace systems have fail-safes built into them to protect you and your home when there is a problem. It is possible that the ignitor of your furnace’s furnace could malfunction if your furnace suddenly stops blowing warm air.

Clean the air filter. It prevents air from flowing properly through the furnace if it’s dirty. You might notice that your furnace is not blowing anymore because of this.

The air filter inside your furnace and the air ducts should be cleaned of dust and debris. You may experience your furnace shutting off if something is blocking the airflow through the filter or your vents.

If the air passageways seem free of obstructions and your air filter seems clean, the next best option is to inspect the ignitor.

The Furnace Won’t Come On

The Furnace Won't Come On

A problem with the ignitor could result in your home becoming increasingly cold, yet the furnace never fires up, no matter how high you set the thermostat.

Make sure you perform the thermostat checks mentioned above. In any case, check your breaker box to ensure that the switch connected to your furnace hasn’t been tripped to “off.”

Here’s how to locate your breaker box if you’ve never found one before.

View the switch that controls the power to the furnace. If your furnace’s breaker is on, its ignitor might be broken, or there may be a significant electrical problem.

No Cold Air

A faulty ignitor prevents the furnace from creating a tiny spark that heats the air circulating. With your heater on, as well as cold outside air, you are blowing the same temperature air.

If your vents are blowing cold air, this indicates that your furnace is having heating problems. There might, however, be a simpler way to resolve the problem. To ensure the thermostat is set for heat, instead of cool, ensure it is set for “heat.”

You should set the furnace temperature high enough to tell it to blow hot air. When the thermostat is set to the right temperature, the following simple solution might be an issue with the ignition.

What Are Possible Ignitor Problems?

What Are Possible Ignitor Problems

Ignitor problems can be caused by many factors, including:

  • Getting old and worn out. It may be close to the end of its life if the ignitor is old. Replacement is needed.
  • That’s the wrong one. For your furnace to work, the right ignitor is required. A new ignitor should be purchased if you are using the wrong one.
  • The limiter switch is not working properly. You’ll lose heat if your switch fails and shuts off your furnace.
  • It is overpowered. You may have an ignitor that cannot tolerate a surge of power if the breaker box blows when the furnace turns on.

When you don’t have the tools and knowledge to test your ignitor, it can be difficult to determine the cause of the problem. If an igniter shows visible damage, it is most likely faulty.

The manual for your furnace will tell you what to do. If you need to replace the ignitor, make sure you choose the right one. There could be a mechanical issue if there is no visible damage. Restart the power supply and observe the results.

  • Inducer motors should kick-start working when they are first turned on. Energy will flow through the wires when the thermostat is heating, causing the inducer motor to work. If there is not enough voltage, it will not start.
  • It is important to have a pressure switch that allows ignition. You can generally hear a ‘click’ sound about 10-15 seconds after the inducer motor starts working. When the gas valve opens, this will indicate a pressure switch was triggered.
  • Ignitor activation and heating are expected. Whenever the ignitor energizes the gas valve, an ignition spark is ignited. An orange/yellow glow is anticipated from the ignitor.

There should be a way to observe these activities in the system. You can move on to the next stage of diagnosis if any of the above don’t occur.

Make sure you call a professional! You can risk your safety and furnace if you attempt a repair. If you are confident that you will be able to handle this task, then go ahead.

How Do I Check the Ignitor?

You can quickly repair and replace the ignitor on your furnace if you feel comfortable touching it up close.

You should check your furnace before opening any panels:

  • Ensure that the furnace is unplugged from the wall. It would be best if you didn’t run the furnace while you searched for the ignitor and replaced it.
  • Turn the gas valve off. You should ensure no gas passes into the furnace while working on it.
  • You should not open any panels before the furnace is at room temperature. If you touch a hot furnace, you could get burned.

Furnace working components may be dangerous to reach. Check to see if it is safe before continuing.

Access is needed to the ignitor. The service panel located on the side of the furnace should be removed. Unscrew any screws or knobs on the panel using a small nut driver.

You will now be able to see the components and connections within the system. You need to find the ignitor among them.

What Happens When the Ignitor Goes Bad on a Furnace?

The furnace ignitor produces a small spark to heat the air coming from the furnace. If the spark isn’t present in the furnace, the furnace can only circulate outside air, regardless of its temperature.

If you notice your ignitor has gone out, change or repair it, whether you do it yourself or hire a professional.

How Long Do Furnace Ignitors Last?

The average lifetime of a furnace ignitor is seven years. How well you maintain your furnace ignitor will have an effect on its life expectancy.

To maximize your ignitor’s performance, it is essential to change furnace filters regularly and schedule yearly technician maintenance.

How Often Should a Furnace Ignitor Be Replaced?

A furnace’s ignitors usually last between four and seven years. In this case, it depends on how well the system is maintained.

It is recommended to replace it after seven years. If you keep your furnace properly, it should easily last you 20 years or more.

How Long Does it Take to Replace a Furnace Ignitor?

In most cases, an experienced technician can change a spark or hot surface ignition in about three minutes and the pilot light in about ten minutes.

Final Words

When you see the first signs of a faulty furnace ignitor, take action as soon as possible. You can investigate the symptoms independently and then contact a professional to handle the repair.

Repairing or replacing the ignitor in your furnace can be a relatively inexpensive fix that can save you from more significant (and expensive) furnace problems. You can also protect yourself from injury or accident by hiring a professional to repair it.

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