How to Adjust an Igniter on an Oil Furnace

Oil furnaces are a really valuable part of your home, and they can help keep you toasty during chilly weather. The igniter, or the probed electrodes attached to the fuel nozzle, is an especially valuable part of the furnace, as it helps...

Cleaning and Realigning Your Igniter

Power down the furnace and close the oil valve. Search around your furnace for an on and off switch. Move this switch to the off position, then search for the oil line, or the pipe that feeds oil into your furnace.^{[2] X Research source} Twist the valve clockwise to lose the oil valve completely, which will stop oil from flowing into your furnace.^{[3] X Research source}
1. The on and off switch is likely attached to your furnace or somewhere else nearby. If you're having trouble finding it, look at your furnace's schematics for guidance.
Turn off the circuit breaker that powers the furnace. Keep in mind that your oil furnace uses electricity to power the igniter, so it's hooked up to a circuit breaker. Switch off any power lines that connect to your furnace, or else you may give yourself a nasty shock while you try to adjust your igniter.^{[4] X Research source}
1. Double-check your home schematics to see which circuit breaker or power lines feed into the furnace.
Unscrew the access panel from the furnace. Look for a large, metal rectangle that's screwed into place on the front of your furnace, otherwise known as the access panel. Remove each of the screws with a screwdriver, then set both the access panel and the screws aside.^{[5] X Research source}
1. The access panel covers the igniter.
Remove the cowling from the side of the blast cone. Look for the blast cone, which is a metal structure attached beneath the main burner in your furnace. Search for a cooler, or conical metal piece, that's attached to the side of the blast code. Twist or slide out the cowler so you can access the fuel nozzle and igniter.^{[6] X Research source}
1. The cowler may twist off like a screw, or you may be able to slide it out, depending on the type of furnace you have.
2. The igniter refers to the 2 large electrodes connected to the fuel nozzle.
Clean out the fuel nozzle and get rid of any oil clogs. Gently pull the fuel nozzle and igniter out of the furnace with both hands and set it on a clean, flat surface. Spritz the tip of a clean cloth with an all-purpose cleaner spray and clean off the cowler, as well as any screws or bolts attached to the nozzle. Spray the cleaning spray down the fuel nozzle along with some compressed air to clean out any built-up oil. Once the nozzle and igniter are clean dry, put the cowler and other small parts back in their rightful places.^{[7] X Research source}
1. If you don't feel confident disassembling and cleaning the nozzle on your own, contact a professional for help.
2. Make sure that the cleaning spray is safe to use on metal.
Attach the igniter wires to the tip of the ignition transformer. Insert the fuel nozzle and igniter back into the blast cone area of the furnace. Look near your ignitor to find the ignition transformer, or a small metal box that helps create a spark in your furnace. Search around the ignition transformer for a place to connect the 2 wires from your igniter.^{[8] X Research source}
1. Don't worry about rewiring anything—just make sure that the wires attached to the igniter connect over to the transformer.
Power on your circuit breaker again. Flip back the switches that power your igniter. Leave the access panel off for now so you can examine your igniter up close.^{[9] X Research source}

Checking for Power

Press the ignition button next to the furnace to see if it sparks. Search around your oil furnace for a red button or other prominent button that ignites your furnace. Press this button once, and look at your igniter to see if there's a visible spark.^{[10] X Research source}
1. If you can see a spark coming from your igniter, you can replace the access panel and turn the power and oil back on.
Shut off the circuit breaker if you don't see a spark. Return to your circuit breaker and flip off any switches that connect to your oil furnace. If you don't turn off these switches, you could be setting yourself up for a nasty shock.^{[11] X Research source}
Test the wires on the ignitor transformer with an ohmmeter to see if they work. Power on an ohmmeter or multimeter and hold the leads attached to the device. Touch these leads to the 2 wires along the ignition transformer and see what reading you get.^{[12] X Research source} If the ohmmeter reads '0,' you'll need to replace the electrodes in your igniter. If you get a reading on your device, then the issue is in some other part of your furnace.^{[13] X Research source}
Check the ignition tip on your ignition transformer with an ohmmeter. Place your ohmmeter leads on the ignition transformer itself, directly where the wires connect to the transformer. If your device doesn't pick up a reading, contact a heating and cooling professional to replace your transformer overall.^{[14] X Research source}