Has your gas oven stopped heating up? Repair Clinic has identified the top 6 causes of this common problem that routinely frustrates those of us who are now unable to bake those cookies or broil that roast. The number one cause of a gas oven not heating up is a faulty oven igniter. Gas ovens will use one of two different kinds of igniters: a hot surface igniter or a spark igniter. If your oven uses a hot surface igniter, get out your multimeter, because we’re about to explain the two important tests you can conduct that can help determine why your gas oven isn’t heating up.
How a hot surface igniter is used to heat a gas oven
As always, it’s going to be helpful to provide some background on how a hot surface igniter is used to heat a gas oven.
The oven control sends 120 volts of alternating current to the bake or broil igniter
When you select the bake or broil function on a gas oven, the oven control sends 120 volts of alternating current to the bake or broil igniter. If the igniter is a hot surface igniter, the component’s filament will begin to glow orange as it heats up. The igniter is wired to a safety valve, and as the component gets hot, it draws an increased current, or amps, through the valve. A bimetal arm inside the valve reacts to the heat generated by the increased current draw which causes the arm to flex and open, releasing gas into the oven’s bake or broil burner tube.
The igniter is now hot enough to ignite the gas into a flame to heat the oven
The igniter is now hot enough that it ignites the gas into a flame to heat the oven. An igniter will remain on to keep the safety valve open until the oven reaches the designated temperature. A thermostat sensing bulb, or an oven sensor, monitors the temperature and when the selected temperature is reached, the control will shut off the voltage to the igniter. The bimetal arm inside the safety valve will then close, shutting off the gas supply to the burner. This cycle is repeated throughout the baking or broiling process to maintain the proper temperature.
The temperature designated by the oven control is only an average
It’s important to remember that the temperature designated by the oven control is only an average as the actual temperature will fluctuate throughout the cycle. Convection ovens can reduce this fluctuation by using a motorized fan, with or without its own heating element, to circulate the heated air more evenly throughout the oven cavity. Still, if you use an oven thermometer, don’t be surprised if the temperature reading doesn’t exactly match that 350° Fahrenheit setting you’ve entered using the oven’s touchpad buttons. In fact, most ovens will take up to an additional ten minutes to reach a designated temperature after the display indicates that pre-heating is done.
Observe whether or not the hot surface igniter is glowing
The first step you should take if your oven is not heating properly is to remove any covers or shields placed over the igniter and burner tube then observe whether or not the hot surface igniter is glowing. If the igniter is glowing but the burner has not been lit after 90 seconds, there is a high probability that the igniter has weakened and is unable to draw the proper amps to open the safety valve and light the burner. Replacing the hot surface igniter with a new one is recommended. However, if you observe that the igniter is not glowing at all, it’s a good idea to test the igniter.
How to test a gas oven’s hot surface igniter
There are two tests you can perform using a multimeter to determine if the oven’s hot surface igniter is functioning properly: a continuity test on the igniter itself and a test to determine if the voltage is reaching the igniter.
Testing for electrical continuity in the hot surface igniter
Here are the 4 steps for testing a hot surface igniter for electrical continuity – a continuous electrical path present in the igniter:
- Remove or isolate the hot surface igniter from the oven (remember to unplug the oven’s power cord or shut off the power supply before removing any panels to uninstall the igniter. This will help you avoid electrical shock).
- Rotate the range selection dial on the multimeter to the lowest setting for ohms of resistance.
- Contact the black meter lead to one of the igniter’s power terminals or wires and the red meter lead to the other power terminal or wire.
- Observe the multimeter display. If the meter display shows a result between 80 and 180 ohms of resistance, the igniter has proper electrical continuity. However, if you see little change in the meter display when the meter leads come into contact with the igniter power terminals or wires, the hot surface igniter has no electrical continuity and has likely burned out.
If the igniter proves to have proper electrical continuity, you will want to test for voltage reaching the igniter.
Testing for voltage reaching the igniter
Here are the 7 steps to test that the appropriate voltage is reaching the igniter:
- Remove any panels to access the power wires leading to the hot surface igniter.
- If you haven’t already done so for the previous test, disconnect the igniter’s wire connector or detach the power wires from the terminals.
- Rotate the multimeter’s range selection dial to “Volts AC”.
- Restore power to the appliance by plugging the power cord back into the electrical outlet or switching the appropriate circuit breaker back on (with the oven receiving power, be sure not to touch any electrical components or wiring with your bare hands).
- Depending on which input you’re testing, select “Bake” or “Broil” on the oven control panel and press the start button.
- Contact the black meter lead to one of the incoming power wire connector terminals or wires and the red meter lead to the other incoming power terminal or wire.
- Observe the multimeter display. The display should indicate close to 120 volts of alternating current available to the igniter. If adequate voltage is present, the igniter is probably faulty or the gas safety valve could be malfunctioning. But if the test determines the igniter is not receiving the proper voltage, the oven’s thermal fuse, temperature sensor, temperature control thermostat, or control board could be at fault.
Explore Repair Clinic’s “Videos & Articles” for free repair content
To help determine the cause of any problem you may be experiencing with your gas oven, we recommend exploring the “Videos & Articles” section of the Repair Clinic website. It’s there that you’ll find free repair content such as the step-by-step procedure to replace a safety valve on a Frigidaire gas oven (model FFGF3052TSA) or troubleshooting tips on why your oven temperature is incorrect. Enter your range or oven’s full model number for model-specific videos, guides, and schematics.
Shop genuine OEM oven parts at Repair Clinic
As your repair partner, Repair Clinic always recommends using genuine original equipment manufacturer (OEM) parts to fix your gas oven or anything other appliance, lawn & garden equipment, or heating and cooling unit. OEM parts are specifically designed to work with the product you’re trying to repair so you stand a better chance of achieving a successful repair with a genuine OEM component than when using a generic part. Shop genuine OEM oven parts by entering the full model number of your oven or range in the Repair Clinic search bar for a complete list of OEM parts compatible with your GE, Bosch, KitchenAid, Electrolux, LG, Kenmore, Samsung, Hotpoint, or whatever other brand name range/oven you need to repair.