Do Furnace Ignitors Wear Out?

Print this articleServicing a furnace used to mean cleaning the unit every few years and forgetting about it the rest of the time. Today’s energy efficient units have many more working parts that need frequent monitoring to keep the furnace in working condition. One of the most troublesome parts is the furnace ignitor, which tend to wear out every three to five years. This part replaces hand-lit burners common in older furnaces.

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The most common cause for ignitor failure is improper handling of the unit itself, particularly for older style gray glass ignitors. Even bumping the ignitor against another part can cause it to crack and wear out more quickly. Homeowners can easily replace ignitors, adding to the problem. When replacing an ignitor, wear gloves so as not to touch the glass portion as skin oils can cause it to burn out. The wrong type will also cause an ignitor to burn out quickly even though it will initially work. Check manufacturer recommendations for the proper replacement part.

Limited Cycling Life

Ignitors have a limited number of on-off cycles, thus two-stage furnaces, which run more frequently, are prone to ignitor problems. Conditions that cause furnaces to cycle frequently will also shorten the life of this part. Short cycling is caused by furnaces too big for the homes they heat. These units turn on and off constantly, even on the coldest days of the year. Dirty filters or blower squirrel cage will prevent the furnaces from getting proper airflow through the heat exchanger. This condition is also a fire hazard. Dirty air conditioning evaporator coils also cause restricted airflow. Coils tend to accumulate dust and dirt on the installation’s underside. Improper thermostat heat anticipator setting is another cause. Setting the amp draw to a slightly higher setting will conserve the ignitor life by causing the furnace to run longer.


Too much gas pressure from the home’s supply line can cause overheating, which results in short cycling because the furnace shuts off frequently to avoid fire. Hissing noises, somewhat like the sound of a jet, are clues that the pressure is too high. To remedy this problem, a professional HVAC technician should adjust the home’s gas valve. Improper adjustment can result in delayed ignition, blow back or a mini explosion.

High Voltage

Too much electricity entering a home can also affect the ignitor. Residential voltage levels should be between 110 and 125. Anything over 125 volts will cause ignitors to wear out quickly. To lower voltage, have your electric company place a transformer on your line.

ReferencesPreferred Home Repair: Gas Furnace Troubleshooting Repair GuideArnold Service: Troubleshooting Heating ProblemsWebHVAC: Prolonging the Life of Your Carrier IgnitorResourcesDSL Reports: Faulty Furnace IgnitorRead Next:

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