How to Tell if Furnace Ignitor Is Bad: The Easy Guide

Wondering how to tell if a furnace ignitor is bad? You’re not alone. Your furnace ignitor is the key to keeping your business warm. Without it, your gas furnace can’t initiate the combustion process that allows you to heat your property. 

A malfunctioning ignitor can often cause perpetuating problems over time, starting with reduced heating efficiency, and ending in full furnace failure. That’s why it’s so important to be able to recognize the signs of a bad furnace ignitor quickly – so you can seek out the right support. 

At DB Sales, we specialize in furnace repair, installation and more – and we know a thing or two about keeping properties warm and comfortable. In this guide, we’re going to walk you through everything you need to know to quickly and accurately identify a faulty furnace ignitor.

What is a Furnace Ignitor?

A furnace ignitor is a central component of a gas furnace, responsible for “igniting” the fuel that starts the combustion process for heating. When a furnace turns on, the ignitor generates a spark, or heat to ignite the burners, and the heating cycle begins, warming the air that circulates through your building.

Older furnace ignition systems typically relied on a pilot flame that burned constantly. Now, most gas furnaces use electronic ignitors – which are generally safer and more energy efficient. Some of the most common types of furnace ignitors include:

• Hot surface Ignitors: HIS (Hot Surface Ignitor) systems use an electric current to heat a silicon carbide or nitride surface. The heat ignites the gas when the furnace starts. These types of ignitors are reliable and efficient, making them ideal for commercial operations. 
• Direct spark ignitors: Direct spark ignitors produce a high-voltage spark to ignite the gas. This type of ignitor is usually found in high-performance furnaces and heat pump systems, as it provides instant ignition without the need to wait for a surface to heat up. 
• Intermittent pilot ignitor: Evolving from the pilot flame systems used in older furnace systems, intermittent pilot ignitors use an electronic spark to light a small flame, which then lights the main burners, enabling the heating process to begin. 

All of these ignitor systems have their own distinct pros and cons. For commercial systems, hot surface ignitors and direct spark ignitors are preferred due to their efficiency, reliability, and safety. However, even these systems can suffer from faults, causing serious disruptions for buildings.

Signs That a Furnace Ignitor Might Be Bad

So, how do you tell if a furnace ignitor is bad? Sometimes, diagnosing an issue isn’t as simple as it seems. For instance, a malfunctioning furnace ignitor won’t necessarily stop working altogether straight away. Here are a few key signs to watch for:

No Hot Air

The most obvious sign that you’re dealing with an ignitor problem, is that your furnace blows out cold air, instead of heat. If your heating cycle is running, but you’re not actually getting any heat from your air conditioning unit, this could mean your ignitor isn’t lighting the burners. 

Before you assume the worst, it’s worth checking your thermostat settings – to ensure there are no issues there. However, if your thermostat is set to “heat” not “cool”, and the temperature is high enough to trigger the heating cycle, it might be time to contact a professional. 

The Furnace Won’t Kick On

If your gas furnace isn’t turning on at all, the ignitor could definitely be the cause of the problem. A properly functioning furnace ignition system should activate when the thermostat signals the need for heat. If the system doesn’t do anything when you turn the heating on, check your thermostat settings, and the breaker box to ensure the furnace hasn’t tripped the circuit. 

You can also listen for the clicking noise of the hot surface ignitor – to see whether it’s actually trying to start the combustion process. If you don’t see any results, you might have a faulty ignitor. 

Furnace Suddenly Stops Blowing

Sometimes, a faulty furnace ignitor can cause the system to shut down unexpectedly. If your furnace starts running but then stops blowing air, it might be because the ignitor isn’t maintaining the combustion process. Many modern gas furnaces have built-in safety measures that shut down the system if ignition fails to prevent gas buildup.

Notably, there are other factors that can cause your furnace to stop functioning suddenly too, such as a dirty air filter, blocked air ducts, or issues with a flame sensor. The best way to find out what’s actually going wrong is to contact a heating repair expert. 

Furnace Starts and Stops Frequently

Inconsistency is the last thing you want from your furnace. If you notice “short cycling” – where your furnace starts turning on and off repeatedly, this could be a sign of a bad furnace ignitor. The hot surface ignitor or direct spark ignitor might not be working correctly, or your ignitor might not be able to hold a charge long enough to maintain a pilot flame. 

Again, other issues can cause similar problems, such as overheating in your boiler or heating system, or flame sensor issues. However, it’s best to call out an expert for a complete evaluation. 

Furnace Trips the Breaker More Than Once

One other common sign that a furnace ignitor is suffering from problems, is that your electrical system starts to malfunction. If your furnace starts up but quickly shuts down due to a tripped breaker, it could mean the ignitor is drawing too much power or causing a short circuit.

While a single trip of the breaker might not be cause for alarm, repeated occurrences indicate a deeper issue. A bad furnace ignitor can overheat and create an electrical overload, forcing the breaker to shut off power for safety reasons.

The trouble with a faulty furnace ignitor, is that it can be difficult to know for certain what’s actually causing the problem straight away. Furnace ignitor issues can be caused by everything from standard wear and tear, to short circuiting issues. The most common root causes of ignitor issues include:

Troubleshooting Furnace Ignitor Issues

If your furnace isn’t working properly, and you think a faulty furnace ignitor might be to blame, you can consider doing some troubleshooting at home. It’s worth remembering, most of the time, you’ll need the support of an expert heating repair company to actually fix the issue. However, troubleshooting can give you a basic idea of what you’re dealing with. 

Before you check on your furnace ignition system, make safety a priority. Turn off the power, to avoid electrical hazards, shut off the gas supply, and let the furnace cool if you were using it recently. Once it’s safe to proceed:

• Visually inspect the ignitor: Locate the ignitor within the furnace by removing the service panel. Look for any signs of damage, such as visible cracks, discoloration, or wear. 
• Check electrical connections: Make sure all the wires connecting your ignitor to the control board are secure. Look for frayed or burned wires that may indicate an electrical issue.
• Test the control board: If you’re experienced with electrical testing, you can use a multimeter to check for voltage at the ignitor connection points to the control board. If no power is being supplied, this could mean the issue is with the control board itself. 
• Inspect the flame sensor: A faulty or dirty flame sensor may shut down your furnace before the combustion process starts. Check that the sensor is clean, and fully functional. 

When to Call a Professional

While basic troubleshooting can help you diagnose ignitor problems, many repairs will require the support and expertise of a professional, like DB Sales. If you notice the ignitor is physically damaged or corroded, for instance, it may need to be replaced entirely. 

If you’ve tried basic repairs yourself, like cleaning the flame sensor, and checking electrical connection points, and you’re still dealing with furnace issues, a professional will be able to identify the cause of the problem and get your system back on track. 

Ultimately, whenever you’re dealing with ignitor problems, unless you have extensive furnace expertise, it’s best to leave the work to the professionals. Attempting DIY repairs yourself risks your safety, and could end up making the issue worse.

Importance of Regular Furnace Maintenance

Even if you’re not dealing with a bad furnace ignitor right now, it’s worth investing some time and effort into regular maintenance, to ensure your system lasts as long as possible. Consistent maintenance can help you detect and resolve issues before they become disruptive and expensive. 

Regular maintenance can:

• Reduce the risk of uneven heating and system failure: When an ignitor begins to wear out, it can struggle to light burners consistently, leading to delayed ignition, uneven heating throughout a building, and even a complete furnace shut down. Routine maintenance helps you to detect issues before they get worse, so you can implement quick repair strategies.
• Improve energy efficiency: A faulty furnace ignitor leads to an inefficient combustion process – causing the furnace to work harder to attempt to produce heat. This can lead to higher energy bills and more wear on your furnace components. During regular servicing, technicians can implement strategies to ensure your system functions correctly, and efficiently, reducing your long-term heating costs. 
• Extend furnace lifespans: A well-maintained furnace lasts significantly longer than a neglected one. Routine furnace maintenance prevents excessive wear on components, reducing the risk of unexpected breakdowns. By ensuring the hot surface ignitor, flame sensor, and control board function correctly, maintenance extends the overall lifespan of your furnace, delaying the need for expensive replacements.

Working with a reputable professional experienced in furnace maintenance and repair helps to ensure you make the most of your system for longer. DB Sales can deliver the expertise and support you need, with tailored maintenance schedules designed to address your specific needs. Contact us to learn more about our flexible maintenance options.

Keep Your Furnace Running Smoothly

A bad furnace ignitor can cause a range of problems for commercial property owners. Even a small problem can quickly lead to inefficient heating, higher energy costs, and unexpected breakdowns. Knowing how to recognize the signs of a faulty furnace ignitor, and when to contact the experts for support, can save you from a lot of headaches. 

As specialists in furnace repair, boiler repair, and commercial heating solutions, DB sales can deliver the support you need to ensure your system not only lasts longer, but maintains exceptional efficiency. Contact DB Sales today to request a quote and ensure your heating system continues to run smoothly all-year round. 

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