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What Causes a Bad Furnace Ignitor? - Aireone

What Causes a Bad Furnace Ignitor?


When a furnace ignitor goes bad, it can be difficult to tell what is happening. This blog explains the different signs that you might see when an ignitor needs to be replaced.

How to Tell If The Furnace Ignitor Is Broken

The most direct way to find out if your ignitor is bad is to test it. If the oven burner does not come on when you press the "ignition" button, then your ignitor needs to be replaced.

7 Reasons For Furnace Ignitor Malfunction

1. Broken thermostat. If the thermostat is set to "cool," but your furnace heats up, it could be because the heating element has burned out or failed.

2. Push-button ignition switch broken. This is one of the most common reasons for furnace malfunctions. It prevents your furnace from heating up properly when broken.

3. Bad or defective capacitor. A capacitor helps control the electronic processes within your heater.

4. Defective fan relay. If you notice that the fan or blower inside your unit is not working properly after replacing your ignitor, it could be because your fan relay has gone bad.

5. Bad gas valve solenoid coil. When this starts malfunctioning, the gas flow to the burner will either be blocked or not shut off completely when you press "ignition."

6. Bad limit control. Limit controls prevent the heating element from overheating.

7. Bad thermocouple. A defective thermocouple is one of the most common reasons for furnace malfunctions.

How To Clean Furnace Ignitor

One way to clean your furnace ignitor is to use compressed air since dirt is the main reason for malfunction. To do this, turn off your furnace and unplug its power source. Next, remove the front grill and blow off any dirt or soot around your ignitor. Once done, wipe the area clean with a damp cloth. 
If you notice that there is still dust and dirt on it, use an old toothbrush to scrub it off. You can also try using steel wool to remove stubborn debris.

When Do You Need to Replace Furnace Ignitor

If the ignitor is covered in dust and dirt, clean it off first. Also, check to see if all wires are connected properly and undamaged. If these do not work, make sure that the power cord is plugged tightly into your furnace or gas valve.
You can also test your unit by inserting an oven thermometer inside the oven and pressing "ignition." If your oven does not heat up at all, the ignitor may need to be replaced.

Furnace ignitors can fail for a number of reasons. Knowing the symptoms that you are looking for makes it easier to detect when an ignitor needs replacement. For furnace maintenance in Toronto contact Aire One Heating & Cooling.

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