Furnace Problem: Electric Ignition

Service Man Inspects Furnace
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Electric systems are safer and more energy efficient than standing pilot designs. But electric systems aren’t without problems. Here’s a quick look at common electrical ignition issues and how you can solve them.

Types of Electric Ignition

Knowing which kind of ignition you have in your home will help you diagnose the problem and communicate with your pro. Here are the two types of electric ignition:

  • Intermittent Pilot. Intermittent designs use a small spark to ignite the pilot and burner. Unlike standing pilot designs, which feature a constantly burning pilot, intermittent designs only light during warming cycles.
  • Hot Surface Ignition. Hot surface ignition systems use electricity to heat metal and ignite the gas burner.

Signs of an Issue

The first step to addressing a malfunctioning igniter is knowing you have a problem. The following are common problems associated with a faulty igniter:

  • Limited heat. A faulty igniter will limit the amount of heat your furnace can produce.
  • Frequent cycling. An unsteady burner will cause your thermostat to constantly start and stop your furnace’s heating cycles.
  • Overactive blower. An inaccurate limiting switch will turn your igniter off, which tells your blower to run to clear the warm air.
  • Lack of maintenance. Hire a pro to look at your furnace if you haven’t had it serviced recently. Some furnace problems are difficult for homeowners to spot, but can still impact your home.

    Call a pro if you notice any of these problems. Sometimes ignition issues are related to a larger malfunction in your furnace. Tackling a repair can lead to damage to your furnace or home.

    Identifying the Problem

    Problems with your electric ignition can vary. Here’s a look at the common causes of faulty electric ignition:

    • Old igniter. Electronic ignition systems aren’t designed to last for the lifetime of your furnace. Have a pro inspect your igniter to ensure it’s in working order.
    • Faulty temperature limiting switch. The temperature limiting switch is a safety feature that turns off the burner when the furnace becomes too hot. Clogged air filters and problems with the switch itself can cause the igniter to turn off early.
    • Wrong igniter. The wrong igniter won’t match your furnace’s voltage, causing it to fail. A mismatched igniter is usually the result of a faulty DIY job.
    • Overpowered current. A surge of power can cause your igniter to burn out. This is especially true with hot surface igniters.

    Before Calling a Pro

    Dirty filters, large electrical surges and tripped breakers can affect your furnace’s ignition. Use this checklist to troubleshoot your furnace before calling a pro:

    Check the Breaker

    Large surges of power can trip your breaker and cut power to your furnace. Make sure your breakers aren’t tripped or blown. Call a professional if your furnace automatically trips or blows its reset fuses.

    Re-light the Pilot Light

    Pilot lights can go out for a variety of reasons. Here’s a quick, step-by-step guide to lighting your pilot:

    • Check the power: The power switch to your furnace should look like a light switch. Make sure it’s in the on position.  
    • Turn off the furnace: Turn off your furnace’s power and gas supplies. Wait several minutes for the gas to clear.
    • Find the ignition button. Turn your furnace back on. Most electric furnaces have an ignition button with a smaller red button next to it. Press the two buttons simultaneously. If your pilot lights, release the ignition button and hold the smaller, red button for one minute.

    Be sure to read your owner’s manual before re-lighting your pilot light. Following your manufacturer’s instructions will ensure you ignite your pilot light correctly. Call a pro if your pilot won’t re-light.

    Replace Filters

    Dirty filters restrict airflow and affect the overall performance of your furnace.

    Swap out your older or clogged filters.

    Check the Gas Line

    Your furnace’s gas line has an on-off valve. Be sure the valve isn’t off or partially closed.

    When to Call a Pro

    If troubleshooting your furnace doesn’t solve your ignition problems, it’s time to call pro. Fixing furnace-related problems requires expert knowledge of gas and electrical systems. A mistake during a DIY repair can lead to gas leaks, carbon monoxide leaks and other hazards. Tackling furnace repairs yourself can also result in expensive mistakes and recurring malfunctions. An HVAC professional will identify your problem and provide an appropriate solution.

    Call a Pro Immediately If You’re Experiencing Any of the Following

    • A strong smell of gas. Gas leaks are a serious threat to any home. Evacuate your home and call a professional immediately if you notice a strong natural gas odor in your home.  
    • Furnace banging or scraping. Scraping or banging sounds are the sign of a serious malfunction. Turn off your furnace and call a professional to make any necessary repairs.