Understanding Furnace Ignitor Problems
A furnace ignitor is the part that lights the gas in your furnace to create heat. When your furnace ignitor stops working, your home won’t get warm. There are two main types of furnace ignitors: hot surface ignitors and standing pilot lights. Hot surface ignitors use electricity to heat up and light the gas. Standing pilot lights stay lit all the time with a small flame. Both types can have problems that stop your furnace from working. Common issues include broken ignitors, dirt buildup, or wiring problems. Knowing which type you have and how to spot problems can help you fix your heat quickly or know when to call a pro.
Table of Contents
| Ignitor Type | How It Works | Common Problems | Lifespan |
|---|---|---|---|
| Hot Surface Ignitor | Heats up with electricity to light gas | Cracks, breaks, wiring issues | 3-5 years |
| Standing Pilot | Small flame stays lit continuously | Drafts, thermocouple issues, dirt | 10+ years |
How Hot Surface Ignitors Work
Hot surface ignitors are the most common type in newer furnaces. They work a lot like the filament in a light bulb. When your thermostat calls for heat, electricity flows to the furnace ignitor. The ignitor then gets very hot, up to 1,800 degrees Fahrenheit!
This glowing hot ignitor sits right next to where the gas comes out. When the gas valve opens, the hot ignitor lights the gas instantly. This creates the flame that heats the air in your furnace.
Hot surface ignitors are made of special materials like silicon carbide or silicon nitride. These materials can handle high heat but are also very fragile. They look like a small, thin stick or flat piece with metal prongs that connect to the furnace’s electrical system.
Common Hot Surface Ignitor Problems
Hot surface ignitors are the number one part that fails in modern furnaces. Here are the most common problems they face:
Physical damage: The biggest issue with furnace ignitors is that they break easily. They’re made of ceramic material that can crack if touched, even when cold. Never touch an ignitor with your bare hands – oils from your skin can cause it to fail faster.
Normal wear and tear: Every time a hot surface ignitor heats up and cools down, it gets slightly weaker. Most hot surface ignitors last about 3-5 years before they need to be replaced.
Wiring issues: Sometimes the problem isn’t the ignitor itself but the wires connecting it. Loose connections or damaged wires can prevent electricity from reaching the furnace ignitor.
Dirt and debris: Dust and dirt can settle on the ignitor, creating a barrier that prevents it from getting hot enough to light the gas. This is why regular furnace maintenance is so important.
Signs Your Hot Surface Ignitor Is Failing
How do you know if your furnace ignitor is causing problems? Look for these signs:
- Your furnace tries to start but no heat comes out
- You hear the furnace click on, but it shuts off before the blower starts
- The furnace cycles on and off repeatedly
- You can see the ignitor glowing, but it doesn’t light the gas
- The ignitor doesn’t glow at all when the furnace starts
If your furnace ignitor is failing, you might be able to see it through the furnace’s viewing window (if it has one). A working hot surface ignitor will glow bright orange or white when it’s heating up.
Understanding Standing Pilot Ignition Systems
Standing pilot ignition systems are older technology but are still found in many homes. Unlike hot surface ignitors, a standing pilot light stays on all the time, even when your furnace isn’t heating.
The pilot light is a small flame that burns continuously, using a tiny amount of gas. When your thermostat calls for heat, the main gas valve opens. The pilot light then ignites this larger amount of gas to create the main flame that heats your home.
Standing pilot systems use a component called a thermocouple to keep safe. The thermocouple is a safety device that senses if the pilot light is on. If the pilot goes out, the thermocouple cools down and shuts off the gas to prevent leaks.
Common Standing Pilot Light Problems
Standing pilot lights have their own set of problems that differ from hot surface ignitors:
Pilot light goes out: The most common issue is when the pilot light simply goes out. This can happen due to drafts, dirty gas ports, or problems with the gas supply.
Thermocouple issues: If the thermocouple gets dirty or wears out, it might shut off the gas even when the pilot is lit. This is a safety feature, but it can be annoying when it happens by mistake.
Dirty pilot orifice: The tiny hole where gas comes out for the pilot can get clogged with dirt or debris. When this happens, the pilot flame may be too small or might not light at all.
Gas pressure problems: If the gas pressure is too low, the pilot might not stay lit. This could be due to issues with your gas supply or problems with the furnace’s gas valve.
Signs Your Standing Pilot System Has Problems
Here’s how to tell if your standing pilot ignition system is having issues:
- The pilot light won’t stay lit after you release the pilot button
- The pilot light is yellow or orange instead of blue
- The pilot light is too small
- Your furnace won’t turn on even though the pilot is lit
- You smell gas near your furnace (this requires immediate attention!)
A healthy pilot light should be blue with perhaps a small yellow tip. If your pilot flame is mostly yellow, it suggests incomplete combustion, which can create carbon monoxide – a serious health hazard.
Comparing Hot Surface Ignitors vs. Standing Pilots
Both ignition systems have pros and cons. Understanding the differences can help you know what to expect from your furnace.
Energy Efficiency
Hot surface ignitors are much more energy efficient. They only use electricity when your furnace is starting up. Standing pilots burn gas 24/7, even in summer when you don’t need heat. This constant gas usage can add up on your energy bills.
A standing pilot light might use $5-$10 worth of gas each month when not in use. That might not sound like much, but it adds up to $60-$120 per year of wasted energy.
Reliability and Durability
Standing pilot systems tend to be more reliable in the long run. They have fewer parts that can break and don’t rely on electricity to work. This means they’ll still function during power outages.
Hot surface ignitors, while more efficient, typically need replacement every 3-5 years. Standing pilot systems can last much longer, though the thermocouple might need replacement every 5-10 years.
Maintenance Needs
Both systems need regular maintenance, but in different ways:
Hot surface ignitors need gentle handling during furnace cleaning. They should never be touched or cleaned directly, as they break easily.
Standing pilots need their flame checked regularly. The pilot orifice and thermocouple may need cleaning to remove soot and debris that builds up over time.
DIY Troubleshooting for Furnace Ignitor Problems
Before calling a professional, there are some safe troubleshooting steps you can try yourself.
For Hot Surface Ignitors
- Check power: Make sure your furnace has power. Check the switch on the side of the furnace (it looks like a light switch) and check your circuit breaker.
- Look for error codes: Many modern furnaces have a small window that shows blinking lights. Count the blinks and check your owner’s manual to decode what the problem might be.
- Inspect the ignitor: If you can see the ignitor through a viewing window, watch to see if it glows when the furnace starts. No glow could mean a bad ignitor or wiring problem.
- Check the air filter: A very dirty filter can cause the furnace to overheat and shut down before the ignitor can do its job.
For Standing Pilot Systems
- Check if the pilot is lit: Look through the viewing window or remove the front panel to see if the pilot light is on.
- Relight the pilot: If it’s out, follow the instructions on your furnace to relight it. This usually involves holding down the pilot button while using a long lighter.
- Inspect the pilot flame: It should be blue and strong enough to reach the thermocouple. A yellow or weak flame needs attention.
- Clean around the pilot: Sometimes gently blowing compressed air around the pilot area can remove dust that’s causing problems.
Safety warning: If you smell gas, don’t try to fix anything yourself. Leave your home immediately and call your gas company from a safe location.
When to Replace Your Furnace Ignitor
Sometimes troubleshooting won’t fix the problem, and you’ll need to replace your furnace ignitor. Here are signs it’s time for a replacement:
- The ignitor is visibly cracked or broken
- The ignitor doesn’t glow at all when it should
- Your furnace keeps failing to light even after cleaning
- The ignitor is more than 5 years old and giving you trouble
Replacing a hot surface ignitor costs about $150-$250 when done by a professional. The part itself usually costs $40-$100, but the labor makes up the rest.
If you’re handy and careful, you might be able to replace a hot surface ignitor yourself. However, working with furnace parts can be dangerous if you don’t know what you’re doing. Always turn off power to the furnace before attempting any repairs.
Preventing Future Furnace Ignitor Problems
An ounce of prevention is worth a pound of cure, especially when it comes to furnace ignitors. Here’s how to keep your ignition system working well:
Regular Maintenance
The best way to prevent furnace ignitor problems is with yearly professional maintenance. A technician will:
- Clean around the ignitor or pilot without damaging it
- Check all electrical connections
- Test the ignitor to make sure it’s working properly
- Clean or replace air filters that could cause overheating
DIY Prevention
Between professional visits, you can:
- Change your air filter every 1-3 months
- Keep the area around your furnace clean and dust-free
- Listen for unusual sounds when your furnace starts up
- For standing pilots, check the flame occasionally to make sure it’s blue and strong
Upgrading Your System
If you have an older furnace with a standing pilot, you might consider upgrading to a newer model with a hot surface ignitor. While the initial cost is higher, you’ll save money on gas in the long run. Modern furnaces are also more reliable and have better safety features.
Frequently Asked Questions About Furnace Ignitors
How long do furnace ignitors last?
Hot surface ignitors typically last 3-5 years before needing replacement. Standing pilot systems can last much longer, but the thermocouple might need replacement every 5-10 years.
Can I replace a furnace ignitor myself?
Yes, but it requires care and some technical knowledge. You’ll need to turn off power to the furnace, identify the correct replacement part, and carefully install it without touching the ignitor element. If you’re not comfortable with this, it’s best to call a professional.
Why does my furnace ignitor keep failing?
Repeated ignitor failures might be caused by:
- Voltage problems in your home’s electrical system
- Gas pressure issues
- A dirty furnace that’s causing overheating
- Poor quality replacement parts
Is it normal for a hot surface ignitor to glow red?
Yes, hot surface ignitors normally glow orange to white-hot when working. This is how they ignite the gas. If your ignitor glows but the furnace still doesn’t light, there might be a problem with the gas valve or flame sensor.
Why won’t my pilot light stay lit?
A pilot light that won’t stay lit is usually caused by:
- A dirty or faulty thermocouple
- Drafts blowing out the flame
- Low gas pressure
- A clogged pilot orifice
Getting Professional Help for Furnace Ignitor Problems
While some furnace ignitor problems can be fixed with DIY troubleshooting, others require professional help. Here’s when to call in the experts:
- You smell gas near your furnace
- Your furnace is making unusual noises
- You’ve tried basic troubleshooting and the problem persists
- Your furnace is short-cycling (turning on and off repeatedly)
- You don’t feel comfortable working with gas or electrical components
Professional HVAC technicians have the tools and knowledge to diagnose furnace ignitor problems quickly. They can also spot other issues that might be causing or contributing to the problem.
Keeping Your Home Warm and Safe
Understanding your furnace ignitor type and common problems can help you stay warm when temperatures drop. Whether you have a hot surface ignitor or standing pilot, regular maintenance is key to preventing issues.
Remember that furnace ignitor problems are one of the most common reasons for heating system failures. By knowing the signs of trouble, you can often catch problems early before you lose heat completely.
For safety and peace of mind, consider scheduling annual furnace maintenance before each heating season. This simple step can prevent many furnace ignitor problems and extend the life of your heating system.
Ready to get your furnace checked or need help with an ignitor problem? Contact Shipton’s Heating & Cooling to schedule an appointment with our experienced technicians. We’ll make sure your home stays warm and comfortable all winter long.