Electric systems are safer and more energy-efficient for furnaces than standing pilot designs that continuously burn using gas. But the electric systems aren’t without their problems. Knowing which kind of ignition you have on your furnace will help you diagnose a problem and communicate with a professional. Here are the two main types of electric ignitions:
- Intermittent pilot: Intermittent designs use a small spark to ignite the pilot and burner. Unlike standing pilot designs, which feature a constantly burning pilot light, 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 a Furnace Problem
The first step to addressing a malfunctioning igniter is knowing you have a problem. The following are common problems associated with a faulty electric 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 off your igniter, which tells your blower to run to clear the warm air.
Call a pro if you notice any of these problems. And make sure to keep up on your regular furnace maintenance, during which the pro can spot problems you might not have seen. Sometimes ignition issues are related to a larger malfunction in the furnace.
Common Causes of Igniter Problems
Problems with an electric ignition can vary. Here’s a look at the common causes of faulty electric ignitions:
- 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 power surge can cause your igniter to burn out. This is especially true with hot surface igniters.
Before Calling a Pro
Factors you can fix yourself, such as dirty filters or tripped breakers, can affect your furnace’s ignition. Use this checklist to troubleshoot your furnace before calling a pro:
Check the Breakers
Make sure your breakers aren’t tripped or blown, cutting power to your furnace. But call a professional if your furnace automatically trips or blows its reset fuses.
Relight the Pilot Light
Pilot lights can go out for a variety of reasons. Be sure to follow manufacturer's instructions when attempting to relight your pilot, and call a pro if it doesn't work. Here are the general steps to relight a 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 red button for one minute.
Replace the Furnace Filter
Dirty filters restrict airflow and affect the overall performance of your furnace. Try swapping your old furnace filter for a new one, and see whether your problem improves.
Check the Gas Line
A 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 a pro. Fixing furnace-related problems requires expert knowledge of gas and electrical systems. And a mistake during a DIY repair can lead to gas leaks, carbon monoxide leaks, and other hazards. Plus, tackling furnace repairs yourself can also result in expensive mistakes and recurring malfunctions.
Furthermore, scraping or banging sounds coming from your furnace are signs of a serious malfunction. Turn off your furnace if you hear these noises, and call a professional to make any necessary repairs.
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.