You’ve set your gas oven to pre-heat at 350 degrees Fahrenheit while you carefully align the final sheet of your much-complimented layer cake. You place the cake in the oven and start cleaning up the cake batter and frosting from the kitchen counter. After a quick chat with a friend, you turn the oven light on to see if the cake is rising. It’s not. Opening the oven door, you realize the temperature in the oven has not risen above the temperature in the kitchen. Why won’t the oven heat up? To understand that, you should probably understand how a gas oven works.
How gas ovens work
When you select the bake or broil function on a gas oven, the control sends 120 volts of alternating current to the bake or broil igniter or spark electrode. 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 amps which causes the arm to flex and open, releasing gas into the oven’s bake or broil burner tube. The igniter or spark electrode then 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.
Keep in mind, the temperature designated by the control is only an average; the actual temperature will fluctuate throughout the cycle. Convection ovens will reduce this fluctuation by using a motorized fan, with or without its own heating element, to circulate the heated air evenly throughout the oven cavity.
Top reasons why a gas oven won’t heat
Provided the range or oven is receiving incoming power and other components (such as light bulbs and cooktop burners) appear to be working properly, the most likely causes for why the oven won’t heat are:
- Faulty igniter – Over time, an igniter can weaken and fail to open the safety valve correctly. You should remove any covers or shields and, after turning the oven on, observe whether or not the igniter begins to glow. If the igniter does begin to glow, but the burner does not light within ninety seconds, the igniter is probably faulty. You can use a multimeter to test the igniter for continuity – a continuous electrical path present in the part. If the igniter tests negative for continuity then it has failed completely and will need to be replaced.
- Damaged spark electrode – Some range ovens will use a spark electrode to ignite the gas in the burner tube similar to a spark plug. Any cracks in the porcelain housing or damage to the electrode tip could indicate that the component has failed.
- Defective thermostat – As noted earlier, the thermostat monitors the oven temperature and determines when the voltage should be shut off to the igniter. If the thermostat is defective, the igniter may not receive any voltage at all. As with the igniter, you can use a multimeter to help determine if the part has electrical continuity or not.
- Loose or burnt wire connection – An igniter or electrode power supply wire will commonly burn out near the heat source and appear visibly damaged. You should confirm the wire is free of damage and the wire connector is secured.
- Defective safety valve – Although it’s not a common problem, the bimetal arm inside the safety valve may fail to open, preventing gas from entering the burner tube. Again, you can use a multimeter to test the valve for continuity which will determine if the valve has failed electrically.
- Malfunctioning oven control board or relay board – If you’ve ruled out the failure of other oven components, then it’s possible the oven control, or relay, board is malfunctioning. While the board cannot be easily tested, you can always inspect it for signs of burning or a shorted-out component.
Find the right gas oven parts with Repair Clinic
Repair Clinic stocks all the replacement parts that can keep your gas oven baking and broiling as expected, including igniters, spark electrodes, thermostats, oven sensors, oven safety valves, and oven control boards. Enter the full model number of your range or wall oven in the Repair Clinic website search bar to see a complete list of compatible parts, then use the part category and part title filters to narrow the list down to identify the exact part you need. While Repair Clinic carries parts that fit ovens from top brands like GE, Bosch, KitchenAid, Electrolux, LG, Kenmore, Samsung, and Hotpoint, you’ll want to make sure you’re selecting a part that is directly related to your specific range or oven model.