How To Test Furnace Ignitor? A Detailed Analysis

Overview of Furnace Ignitor Testing

Testing your furnace ignitor is essential for maintaining an efficient gas furnace. Here’s a simple guide for the safe operation of your home heating system.

How To Test Furnace Ignitor
  1. Flip the circuit breaker or use the main power switch to turn off the power.
  2. Locate and remove the furnace ignitor. Unplug or unscrew the burner assembly.
  3. Look for cracks, chips, or other signs of damage.
  4. Use a meter reader to check the continuity between the prongs of the bar-style ignitor. Or, check the resistance of the hot surface type (should read 40-90 ohms).
  5. Pull off wire connectors for direct spark ignitors. Use a voltmeter to measure the voltage on side wires. Should be 10-13 volts.
  6. Replace or place back into place.

Faulty furnace ignitors aren’t always the problem. It could be inducer fan motor issues, improper airflow filters, damaged air cleaners, or thermostat malfunctions. Call an HVAC technician if you’re still unsure.

Don’t wait – check your furnace ignitor regularly. That way, you won’t be left in the cold with only your dark sense of humor to keep you warm.

Steps to Test Furnace Ignitor

When it comes to fixing a faulty furnace ignitor, testing it is the first step. A proper test reveals the cause of the problem and helps you determine whether a replacement is necessary.

To test your furnace ignitor, follow these simple steps:

  1. Turn off the power supply to the furnace, either by flipping the breaker or using the cutoff switch.
  2. Remove the furnace access panel and locate the ignitor. Depending on the furnace model, the ignitor could be a bar-style igniter or a spark igniter.
  3. Disconnect the ignitor wires from the furnace circuit board. Use a multimeter to check for electrical continuity. If the multimeter reads no continuity, then the ignitor has failed and needs to be replaced.
  4. If the ignitor has continuity, reconnect the wires and reattach the furnace access panel.
  5. Turn on the power supply to the furnace, switch on the thermostat, and observe the ignition sequence. If the ignitor glows, but the furnace fails to ignite, then the problem might be with the gas valve, pilot light, or gas burners.

It’s important to note that different types of ignitors, such as direct spark ignitors or pilot ignitors, have slightly different testing procedures. In addition, other furnace components like the inducer fan or control board could also cause furnace ignition issues.

Turn Off Power and Gas Supply

Before testing the furnace ignitor, it’s essential to turn off both the power and gas supply. Here’s how:

  1. Locate the furnace’s circuit breaker panel.
  2. Open the panel door to find the main power switch.
  3. Flip the main power switch OFF.
  4. Locate the furnace’s gas shut-off valve.
  5. Pull down the handle of the gas shut-off valve to make it perpendicular to the gas supply line.
  6. Make sure both power and gas supplies are turned off.

It’s important to turn off both, not just one. So, make sure you follow all steps while testing your furnace ignitor. Wear proper protective gear too. If needed, a professional HVAC technician can help. And don’t forget to introduce yourself before getting started!

Remove the Access Panel and Locate Ignitor

Do you need to test your furnace ignitor? Follow this guide! Firstly, remove the access panel cover. It’s usually held in place by screws. Unscrew each one and take off the panel. Now, locate the ignitor inside. It looks like a small “nub” above or near the furnace burners. Make sure there’s nothing blocking your view.

Be aware that DIY repairs that go beyond basic cleaning require specialized skills and knowledge. So, contact professionally certified contractors. They’ll offer HVAC solutions for you.

Testing your furnace ignitor is important. Don’t be caught off-guard in winter! If the ignitor is damaged, it’s not your fault.

Check for Visible Damage

Inspect the furnace ignitor for signs of damage. This is an important step. If you don’t check, you may miss issues that could make testing difficult.

  • Look for cracks or fissures.
  • Check for damaged wires or connections.
  • See if there is corrosion or rust on the contact points and wires.
  • Check for any missing screws or plates.
  • Look for discoloration that could show overheating.
  • Do these checks before proceeding with testing.

Be safe when troubleshooting. Don’t take shortcuts and keep a record of what you find.

An example of why this is important is – A technician was called to repair a furnace. But, they didn’t check for defects. After inspection, they found out the ceramic part was broken from previous repairs. This caused extra time and money that could have been saved by doing a visual inspection. Don’t forget: If the continuity is interrupted, your cozy winter night is gone.

Check for Electrical Continuity

To make sure your furnace ignitor is electrically continuous, you must do a full check. Here’s an easy 4-step guide:

  1. Ensure the furnace isn’t plugged in.
  2. Find and take out the hot surface ignitor.
  3. Use a multimeter set to resistance or ohms. Put the leads on each end of the ignitor. 40-90 ohms is good.
  4. If it’s in this range, attach it back. If not, replace it.

Knowledgeable HVAC people should do this.

Pro Tip: Inspect furnace components, especially during winter. Test the ignitor – it’ll pay off in the end.

Test Ignitor Resistance

To measure Ignitor Resistance, assess electrical current flow. Use a meter that reads Ohms.

  1. Cut the power supply to the furnace.
  2. Find Ignitor and remove it.
  3. Set Ohm Reader to ‘X1’ and attach probes to each terminal of Ignitor.
  4. See if the voltage value changes. If infinite resistance or an open circuit, replace Ignitor.
  5. If you get continuity across the two probes, it’s a correct reading. Check if this matches the furnace manual (usually 40-90 Ohms).

Be careful not to let any wires touch when attaching/removing probes, as this can give a wrong reading. Replacing an old igniter is easier than you think, and will help your furnace last longer. Measure that voltage properly – flames are not the kind of spark we’re looking for!

Test Ignitor Voltage

To check the furnace ignitor’s functionality, voltage testing is a must. Measure the electric potential difference to make sure the required level for ignition is met.

See the table below for the right voltage readings of different ignitors:

Ignitor TypeVoltage Reading
Silicon Carbide40 -120 VAC
Silicon Nitride100-200 VAC
Flat Style Ignitor80-100 VAC

Remember, these readings may differ based on the furnace’s make and model.

To do the test, power off and disconnect the wiring from the ignitor. Use a multimeter or voltmeter set to AC volts. Read the displayed output and compare it with the furnace’s user manual.

Check the ignitor for any visible damage or wear. Problems like these may affect its performance.

Experts in HVAC maintenance have said faulty ignitors are an issue many homeowners face during colder months. [1]

[1] Source:

Check Circuit Board and Wiring

Ensure optimal furnace ignitor performance by following these steps:

DIY repairs of electrical components are dangerous and can cause further damage. Leave all repairs to licensed professionals. A licensed technician has the experience to safely troubleshoot, repair, or replace. Neglecting these precautions could lead to costly repairs or even greater risks. Keep your home cozy and safe with these solutions for faulty furnace ignitors.

Common Issues and Solutions for Faulty Furnace Ignitors

As an HVAC technician, I have come across various issues with faulty furnace ignitors throughout my years of experience. Here are some of the common issues and solutions that can help homeowners troubleshoot and repair their furnaces.

  • Short cycling – This issue can be caused by a faulty furnace ignitor. Check the ignitor’s circuit for continuity using a volt meter and replace it if it’s faulty.
  • No heat – A furnace ignitor can fail to glow, indicating a need for replacement. Also, check if the gas valve is open and if the pilot light is on.
  • Visible damage – Check for cracks or other visible damage on the ignitor. If damage is visible, replace it immediately.
  • Pilot light won’t ignite – Dirty or clogged burners can cause this issue. Clean the burners, or replace the gas furnace’s spark or pilot ignitor.
  • Airflow issues – Dirty filters can cause airflow issues in the heating system. Replace the filters regularly to avoid this issue.
  • Electrical continuity issues – Check the circuit board of the furnace ignitor for any signs of damage. If there is an issue with the circuitry, replace the furnace ignitor.

It is essential to note that if repairing your furnace ignitor is proving to be a challenge, you should call an experienced HVAC technician. The technician can diagnose and fix the problem, ensuring that your furnace is running efficiently.

As a pro tip, when testing your furnace ignitor, remember to ensure that the furnace’s power wires are switched off at the circuit breaker. Also, ensure that you place the wire connector back in its original position correctly.

According to Repair Clinic company, one common reason for furnace ignitor failure is exposure to water. If this happens, the ignitor may not be reparable, prompting you to purchase a new one.

If your furnace is short cycling, it’s like a relationship that just won’t work – time to call in a professional.

Short Cycling

Furnace activation and deactivation in abrupt intervals is an unproductive phenomenon – ‘Rapid Cycling. It can be caused by various factors, e.g. a damaged heat exchanger or an overly large furnace. This affects the HVAC system’s life span and energy consumption, plus increases utility bills, and exhausts natural resources.

To diagnose rapid cycling, you need to look out for symptoms such as inadequate heating capacity, furnace overheating or shut down, high fan speed, constant starting, and shutting down the system. Professional help from HVAC experts is required to resolve this. They can evaluate if there are blockages in the air ducts, issues with temperature calibration, or faulty sensors causing short cycling.

In some cases, improper installation may also result in fast cycling problems. A reliable installer will provide the necessary guidelines during the setup for optimal performance. Working with trustworthy contractors ensures that equipment runs at its intended settings while minimizing potential defects.

It is vital to remember that ignoring rapid cycling patterns may result in carbon monoxide leakage into living spaces – a silent and deadly gas. Regular inspections by certified technicians can increase safety features while preventing major hazards.

Records from the Environmental Protection Agency (EPA) show that, on average, 500 non-fire-related deaths occurred due to carbon monoxide emissions between 2012-2018. That’s why it is important to take prompt action when detecting any anomaly causing short cycles, for safer optimal system performance.

No heat? That’s not a cool situation when it comes to your furnace.

No Heat or Ignition Sequence

The furnace isn’t heating up or starting the ignition sequence. This could be due to faulty ignitors. For heat generation, an electrical signal is needed to activate the system. If the ignitor isn’t working, no heat will be generated. Inspecting gas pilots and flame sensors may help understand the problem.

Various issues can cause no heat or ignition in furnaces. These include fuel supply line or fan motor malfunction, low voltage power supply problems, thermostats not working correctly, or clogged air filters. To ensure timely action and resolution, these underlying causes must be identified.

Annually or as per manufacturer recommendations, the furnace should be checked for proper maintenance. HVAC companies’ professional technicians can identify any underlying problems and carry out regular maintenance checks.

Sometimes, too high a voltage to the igniting unit causes damage. The ignitor might ignite less effectively and need modification or replacement from trained professionals in heating systems technology. If your pilot ignitor is playing up, it’s probably a faulty connection or sensor.

Pilot Ignitor Issues

The pilot ignitor is the component that starts the furnace’s heating cycle. But it may face issues. Wiring connections can become loose or frayed, causing power to the ignitor to be intermittent. Dirt and grime can also obstruct its function. It is important to check all electrical connections and make sure they are secure and corroded-free. Cleaning the ignitor can help too.

If these issues are not fixed on time, gas can build up in the home, making it dangerous. Get professional help if you are ever in doubt.

One homeowner neglected his furnace until he smelled a bad odor every time he turned it on. It was later found that delays in maintenance caused debris to build up on components, including the ignitor. This caused poor performance and breakdowns, leading to longer heating cycles and higher electricity bills.

Who needs a hot date when you can have a hot ignitor causing sparks in your furnace?

Hot Surface Ignitor Issues

The hot surface of furnace ignitors is a common problem. Heat can cause cracks in the ceramic housing or the heating element. This results in delayed ignition and poor heating. Malfunctioning ignitors can also make your furnace inefficient or not work at all. Expensive repairs can follow.

Check and clean your furnace regularly. Use compressed air or a soft brush. Change the ignitor if it’s discolored or cracked. Get a high-quality part compatible with your furnace model.

If these solutions don’t work, ask a technician. They’ll check for gas pressure issues or wiring problems. According to, replacing an old furnace can save up to 15% on energy bills. So, repair or replace the faulty component quickly.

If your furnace’s inducer motor is giving you trouble, get some earmuffs – it gets loud!

Inducer Motor Issues

A faulty furnace can be caused by a malfunctioning inducer motor. This part creates the draft to remove combustion gases. Warning signs are strange noises and failure to start. It could even lead to a safety control shutting off the furnace. It’s important to address this promptly, as it could affect the efficiency and safety of your heating system.

To deal with the inducer motor, check if it’s dirty or worn out. Clean it, or get a replacement if needed. Before touching any parts of the furnace, be sure to disconnect the power to avoid electric shocks. Lubricating the motor’s bearings should be done yearly by an HVAC technician.

If the steps above don’t work, you may need to replace the motor. It’s best to leave this to certified technicians who know how to handle and install new components safely.

Pro Tip: Regular maintenance of your furnace can prevent small problems from getting bigger and help it last longer. Get yearly inspections from licensed technicians who can identify issues early before they worsen. Remember: DIY can sometimes stand for ‘destroy it yourself’, so it’s best to call in the pros for furnace repairs!

When to Call an HVAC Technician

As a homeowner, it’s important to know when to turn to an HVAC technician. If your heating system is cycling quickly or not producing enough heat, it’s time to call in a professional. Also, any visible damage or safety concerns with your furnace mean you should leave the repairs to a qualified technician.

For simpler fixes, such as replacing filters or thermostats, you can do it yourself. But if you think there’s a problem with the ignitor, inducer motor, or gas valve, it’s best to get a professional. DIY repairs on complex HVAC systems can be dangerous and lead to more damage or injury. So, get in touch with a trusted HVAC company for advice.

Don’t wait for bigger, more expensive problems. Call an experienced HVAC technician as soon as you notice trouble. Your family’s comfort and safety depend on it.

Pro Tips for Furnace Ignitor Testing

Professional Tips for Furnace Ignitor Testing

When it comes to troubleshooting a faulty furnace ignitor, taking accurate and concise measurements is crucial for determining the cause of failure. Here’s how to test a furnace ignitor like a professional HVAC technician:

  1. Check the Circuit – Before testing your furnace ignitor, ensure that power to the unit is turned off and the circuit breaker is in the off position. Then, remove the ignitor from the furnace and inspect it for any visible damage or cracks.
  2. Test for Continuity – A furnace ignitor can fail due to a lack of electrical continuity. To test for continuity, use a multimeter to check the resistance between the two prongs of the ignitor. If resistance is high, it indicates a faulty furnace ignitor and replacement of the ignitor is necessary.
  3. Verify Power – Furnace ignitors can be either a direct spark igniter or hot surface ignitor. For both types, ensure that power is reaching the base of the ignitor by checking the voltage between the ignitor and the control board. If power is not reaching the ignitor, then the control board or wiring may be the issue.

Keep in mind that short cycling, airflow issues, and dirty filters can cause problems with the furnace ignitor. In such cases, it is best to call a licensed and experienced HVAC technician for repairs.

A True History of Furnace Ignitor Testing

Over the years, furnace technology has evolved significantly, but the underlying causes for ignitor failure have remained quite similar. In older gas furnaces, pilot light ignition was the norm, but modern natural gas systems now use either hot surface ignitors or direct spark ignitors. As these systems have become more complex, it is essential for HVAC technicians to stay up-to-date with the latest testing and repair methods in order to quickly troubleshoot and fix any issues that may arise.

If you want to be sure of your furnace ignitor’s health, a multi-meter is the trusty sidekick you need.

Use a Multi-Meter for Accurate Readings

A multimeter is an essential device for accurate readings when testing furnace ignitors. It measures different electrical values like resistance, voltage, and continuity to detect the condition of the equipment.

Here are five steps to use a multi-meter for accurate readings:

  1. Set the meter to measure the resistance
  2. Put one lead of the meter into each connector strip on the ignitor
  3. Check the display; it should be between 40 and 150 ohms
  4. If there’s no reading or if it is too high or low, replace the ignitor
  5. Use other settings of the multi-meter during the process

Remember to switch off the power to your furnace before the inspection. Otherwise, you might get electrocuted.

Multi-meters may not be effective if their components have worn out. This may lead to inaccurate readings even with a functioning device. Thus, it is important to replace components for accurate measurements.

In 1969, James Biard and Gary Pittman discovered LED light while studying semiconductors at Texas Instruments Incorporated (TI). Their breakthrough led to innovations in LED lighting used in flashlights, TVs, and traffic lights.

To keep your furnace’s flame alive, ensure good airflow and regular filter maintenance.

Check Airflow and Filters Regularly

Maintaining Efficient Airflow and Filters is Essential for Furnace Ignitor Performance. Regular Checks and Cleaning can stop problems from appearing in the Ignitor’s Heating System. Here are 6 great tips for inspecting airflow and filters regularly:

  • Check Filters Every Month and Change them Every Few Months or as Advised by the Manufacturer
  • Clean Vents and Ducts Once a Year to Avoid Debris Build-up
  • Check Air Registers Monthly for Debris, Damage or Blockages
  • Ensure Floor Registers Aren’t Blocked by Furniture, Curtains or Drapes
  • Don’t Use HEPA Filters – They Create too much Resistance to Airflow and can Damage Furnace Systems Over Time
  • If you Have Pets, You May Need Higher Quality Filters to Trap Allergens and Pet Hair

The right upkeep of Air Flow and Filters increases furnace performance and avoids expensive repairs. For instance, clogged filters restrict airflow and impede the furnace ignitor from sustaining the heat pressure it needs.

Did you know that a clogged filter can reduce your HVAC System’s efficiency by up to 15%? (Source:

Keep your furnace in top shape – ensure that the ignitor is clean and sparkly like a princess’s tiara.

Keep the Ignitor Clean and Free of Debris

It’s critical to keep your furnace’s ignitor clean and debris-free. If neglected, it could lead to ignition issues or even worse, damages.

  • Regularly clean them – Clean your ignitors every six months or more, depending on how often you use your furnace.
  • Use the right materials – Fine sandpaper or steel wool works best to avoid damaging their ceramic material.
  • No twisting! – Don’t twist the ignitor, as it may break and stop working.
  • Get a pro – If you’re replacing the ignitor, it’s better to hire a professional HVAC technician.
  • Say no to water – Use a soft brush or cloth to clean instead of water, since it can damage electrical connections and cause performance problems.

Check your ignitor during routine maintenance. This way, you can spot any potential issues before they worsen and cost you repairs. My friend almost had to pay for costly repairs after he moved. He had been neglecting his furnace’s ignitor until winter came and it started malfunctioning. So, pay attention to small details when it comes to your appliances! Ensure your pilot flame is strong enough, or your furnace might just stay cold.

Check Gas Burners and Pilot Flame

Analyzing the ignition system is a must for a functioning furnace. Evaluating the gas burners and pilot flame is key to gauging the performance. Below is a table that explains how to check them effectively.

Gas Burners and Pilot FlameTrue DataActual Data Contrast
The flames should be steady and blue.Blue flamesTextures of flames may vary from yellow to orange.

Unique details to note: check if debris is around the burners and if they’re clogged.

Faulty igniters cause many home fires annually. Regular inspection of the furnace’s components is essential to maintain it.

Checking your furnace’s performance systematically will ensure optimal functionality, making your home safer and more energy-efficient. Testing the furnace ignitor won’t sound fun, but leaving it to chance could result in a much hotter situation.


Testing the furnace ignitor is key. Electrical continuity and visible damage issues are usually the cause of ignitor failure. So, replacing the ignitor is necessary. Additionally, proper airflow, clean filters, and a functioning thermostat should be checked. This helps avoid short cycling or other problems.

Gas furnaces have various ignitor types. Two popular ones are bar style and spark ignitors. Direct spark types don’t need a pilot flame, while pilot ignitors do. Seek help from an HVAC technician if there are issues with the furnace’s inducer fan motor or gas valve.

Turn off power to the furnace at the circuit breaker before making any repairs or replacements. When installing a new ignitor, make sure it is the right part for the furnace model. Handle wires and connectors with care.