Furnaces are complex systems, featuring numerous small parts with big jobs. Responsible for lighting the burners that produce heat, the furnace ignitor is among the most vital parts of your heating system. If your furnace suddenly can’t keep up with heating demands, the ignitor may need attention. Learn how to tell if your furnace ignitor is bad and how G & R Heating and Air can repair and maintain your system.
Understanding the Furnace Ignitor
Modern furnace systems use ignitors to light the fuel and generate heat, replacing the standing pilot lights of older models. When your thermostat signals the furnace to begin heating, the ignitor activates, heats to a high temperature, and ignites the gas supply.
There are several types of furnace ignitors, including:
- Hot surface: The most widely used ignition system, hot surface ignitors use electrical current to heat the element, igniting the fuel. Since they activate only as needed rather than continuously consuming fuel or electricity, hot surface ignitors are highly energy-efficient and reliable.
- Direct spark: Found in some modern furnaces, direct spark ignition systems use a high-voltage electric spark to ignite the main burner instantly. Like hot surface ignitors, direct spark igniters are energy-efficient because they activate only when needed.
- Intermittent pilot: These ignition systems also use electric sparks, but they ignite the pilot flame as needed rather than the burner. The pilot flame then ignites the main burners. After ignition, the pilot flame shuts off to conserve gas.
Signs of a Bad Furnace Ignitor
Ignitors are subjected to intense temperatures and gradually degrade until they need replacement, usually after three to seven years. Excessive voltage fluctuations, power surges, or debris can also weaken or crack an ignitor, accelerating its wear.
Without a furnace ignitor to light the burners, your furnace cannot produce heat. Recognising these signs of a bad furnace ignitor early allows you to address problems before they escalate to more serious issues.
Diminished or inconsistent heat
Inconsistent or insufficient heating is one of the first signs of an ignitor problem. If your furnace turns on but cannot meet or maintain the set temperature, the ignitor may be failing. A degraded ignitor may be unable to reach the required temperature to ignite the burners, leading to minimal or no heat output. The ignitor may be working sporadically — sometimes igniting the burners and sometimes failing to ignite them.
Unusual noises
Furnaces operate relatively quietly, usually starting a cycle with a subtle click and maintaining a light hum as the blower fan distributes warm air. If an ignitor produces unusual sounds, it usually indicates a fault. For example:
- Repeated clicking: One click is normal, but repeated clicks indicate the ignitor is trying to ignite the burners but failing.
- Buzzing: Electrical issues within the ignitor may cause it to operate improperly and emit a buzzing sound.
- Popping or banging: Delayed ignition can cause excess gas buildup in the combustion chamber, leading to a small explosion that creates popping or banging sounds when the burner eventually ignites.
Visible damage or wear
Cracks, discolouration, scorching, or other visible wear may mean that your ignitor is at the end of its operating life and due for replacement. Hot-surface ignitors are made of silicon carbide or silicon nitride and eventually crack when exposed to high temperatures. Even if your ignitor is still partially functional, these problems worsen, impede furnace performance, and potentially damage your system.
Failure to ignite
While damaged ignitors may retain some normal function and fail only sporadically, others may fail altogether. The furnace may attempt to start but shut down after a few seconds, and the ignitor may glow but fail to light the burners, or not glow at all. Modern furnaces feature safety sensors and mechanisms that trigger a shutdown if they don’t detect a flame or sufficient heat, preventing gas leaks or explosions. Repeated shutdowns may cause your furnace to go into lockout mode, where it won’t operate at all without professional repair.
Repeated circuit breaker trips
If the furnace ignitor’s electrical components are faulty, it may draw excessive current and overload the circuit, causing a circuit breaker to trip. Resetting the breaker usually resolves one-off surges, but repeated breaker trips suggest a more significant problem with your furnace.
Multiple trips indicate underlying issues with your furnace, electrical system, and household, and the furnace breaker should be switched off until a professional diagnosis and repair are performed.
Diagnostic Tools and Professional Inspection
Don’t ignore potential furnace ignitor problems — left unaddressed, they may escalate, leaving you without heating and vulnerable to the harsh Illinois winters. Basic upkeep may sometimes resolve furnace performance concerns. To test your furnace ignitor, first check that your thermostat is set to heating mode and that its temperature settings are correct. Replace air filters as needed, check for tripped circuit breakers, and open all air duct vents. If the signs of a faulty ignitor persist, consult a professional HVAC technician.
Diagnosing a faulty ignitor requires specialised tools and professional expertise. While some signs of failure are clear, professional testing guarantees an accurate and safe assessment to prevent further problems and minimise hazards. Depending on their findings, your technician may use one or more of these troubleshooting steps:
- Visual inspection: A technician will check for cracks, wear, or contamination with safe handling techniques to prevent damage.
- Check furnace error codes: Modern furnaces often feature a blinking light system that communicates specific error codes, such as ignitor problems.
- Multimeter testing: Measures electrical resistance in the ignitor to determine if it’s malfunctioning or damaged.
- Flame sensor inspection: Dirty or malfunctioning sensors prevent proper ignition.
- Gas pressure check: Inspect the gas supply components, such as the valve, to verify that gas reaches the burners at the correct pressure.
If your furnace isn’t working properly, the safest solution is to contact G & R Heating and Air, where certified technicians can diagnose and resolve the issue through repair or component replacement.
Preventive Maintenance and Replacement
Ignitors have limited lifespans and are among the most commonly replaced furnace components. If the ignitor is damaged or failing, replacement is a preventative measure against future malfunctions. Routine maintenance helps prevent premature ignitor failure and provides other benefits, such as:
- Reducing strain and wear on the heating system
- Improving energy efficiency and lowering heating costs
- Minimising the risk of emergency repairs
- Ensuring safe operation, minimising the risk of gas leaks, fires, or electrical problems
Want to Learn More About Smart Faulty Furnace Ignitors? Contact the Professionals at G & R Heating and Air
A malfunctioning ignitor may leave you without heat when you need it most. Keep your home comfortable and safe with professional repair for a bad furnace ignitor from G & R Heating and Air. If you’d like to learn more about furnace systems in Northern Illinois, or if you need to schedule a free second opinion, contact our office or call us today.
