how to tell if a furnace ignitor is bad

3 min read 17-01-2025

Your furnace is a vital part of your home's comfort, especially during cold weather. When it malfunctions, identifying the problem quickly is crucial. One common culprit is a faulty ignitor. This article will guide you through the signs of a bad furnace ignitor, helping you determine if it's the source of your heating woes. Replacing a furnace ignitor is often a DIY-friendly repair, saving you money on service calls. However, always prioritize safety and consult a professional if you're uncomfortable working with gas appliances.

Signs Your Furnace Ignitor Needs Replacing

A failing furnace ignitor doesn't always announce its demise with a dramatic bang. Instead, it often presents a series of subtle symptoms that, when combined, point towards the need for replacement. Here are some key indicators:

1. Furnace Won't Turn On

The most obvious sign of a problematic ignitor is the complete failure of your furnace to ignite. If you hear nothing when you switch it on, the ignitor could be the problem. This is often accompanied by a lack of heat output, leaving your home cold and uncomfortable.

2. Clicking or Clicking Sounds

A repetitive clicking sound emanating from your furnace is a strong indicator of a faulty ignitor. This signifies the ignitor attempting to spark but failing to do so consistently. The clicking continues as the system tries repeatedly to ignite.

3. No Glow During the Ignition Sequence

Many furnaces have a visible ignitor. Observe the ignition sequence; you should see a bright orange glow if the ignitor is working correctly. If you don't see this glow, it suggests a problem with the ignitor itself, preventing successful ignition.

4. Intermittent Heating

The furnace may work sometimes but fail to light other times. This intermittent heating suggests a failing ignitor that is only sporadically able to generate the necessary spark to ignite the burner. It's an unreliable heat source.

5. Error Codes on Your Furnace Display

Modern furnaces have digital displays that provide error codes. Consult your furnace's manual to determine if the error code relates to the ignitor. These codes offer more precise diagnostics than solely relying on auditory or visual cues.

6. Pilot Light Issues (If Applicable)

For furnaces with a standing pilot light, an inability to keep the pilot lit can also suggest a problem with the ignitor or its associated components. This often manifests as a pilot light frequently going out.

How to Test Your Furnace Ignitor (Proceed with Caution!)

Disclaimer: Working with gas appliances is dangerous. If you're not comfortable with this, call a qualified HVAC technician. Improper handling can result in gas leaks, fires, or explosions.

If you decide to proceed, follow these steps:

Turn off the power: Locate the furnace's power switch and turn it off. This is crucial for safety.
Inspect the ignitor: Carefully examine the ignitor for visible damage, such as cracks or burns.
Check for continuity (Advanced): Using a multimeter, test the ignitor's continuity. This requires technical expertise and understanding of electrical circuits. A failed continuity test usually indicates a bad ignitor. (Consult online resources or a professional for guidance on this step).
Observe the glow (if accessible): With the power back on, carefully observe if the ignitor glows orange during the ignition sequence.

Replacing Your Furnace Ignitor

Once you've confirmed a faulty ignitor, replacing it is often a straightforward task. However, remember to always follow the manufacturer's instructions precisely and consult your furnace's manual. There are many online video tutorials available, but again, prioritize safety. If you're at all unsure, call an HVAC professional. This is especially true for gas furnaces.

Replacing the ignitor might require access to specific tools and parts. Purchasing the correct replacement ignitor for your furnace model is crucial for proper operation.

Conclusion

A malfunctioning furnace ignitor can leave you shivering in the cold. By understanding the telltale signs – from no ignition to intermittent heating and clicking sounds – you can quickly diagnose the problem. While replacing the ignitor is often DIY-friendly, remember to prioritize safety. When in doubt, always seek professional help to avoid potential hazards. Addressing a faulty ignitor promptly ensures the reliable and safe operation of your furnace, keeping your home warm and comfortable.