Hi, it’s Steve from PartSelect. Today, we’re going to try to determine the cause of gas oven not lighting or not heating. Remember, parts are specific to your model of oven and the one shown today may not be the right parts for you. To get the right part for your oven, be sure to search PartSelect.com using your model number. If you need help finding your model, use our model number locator. The link is in the description: https://www.partselect.com/Model-Number-Locator+1+repair.htm.
Gas ovens burn either propane or natural gas. Most gas ranges currently available use one of three basic gas ignition systems: a pilot flame, a spark ignitor, or a hot surface ignitor. The last two are referred to as electronic ignition systems because they use electricity to light the oven burner. Only the pilot ignition system has an actual pilot flame to light the burner.
Even though your oven is heated by gas, the controls are electric and must be powered to work properly. Whenever you have an electric appliance that will not turn on, the first thing to check is the power supply. Make sure everything is plugged in and the core is in proper working condition.
The next thing you would check is the gas supply. Make sure that any manually operated supply valves are in the on position and that there are no kinks in the gas line. This will also include checking to ensure there are no obstructions in the burner tube connecting the orifice of your gas valve to the burner. This could include cobwebs, soot or cooking debris. If you still have no gas supply to the ranger oven, then you should contact a qualified gas service technician. If the surface burners of your range function properly, then you can assume the gas supply is OK. If the surface burners of a range are spark ignition type, the oven will typically have an electronic ignition system, and therefore should not have a pilot light. Please remember that just because the surface burners might light by a spark, that doesn’t necessarily mean the oven uses a spark type ignition system too. Hot surface ignitors are the most common source of oven ignition on ranges that have spark ignitors for the surface burners.
What happens with a glow bar ignition system is that the thermostat or electronic control closes the switch to supply the line voltage power to the oven ignitor and gas valve circuit. This current flows through this circuit, the ignitor heats up and begins to glow. When the ignitor gets hotter, it draws more current than when the current level reaches a specific amount. A bimetal inside the oven safety valve will activate and allow gas to flow and the glowing hot ignitor will ignite it.
Power must continually flow through the ignitor and the oven gas valve for gas to be released into the oven burner to create a flame. Once the set temperature is achieved, the control stops. All power to the ignition circuit, which causes the ignitor to dim and the oven gas valve to close, stopping any burner flame. Cycling on and off continues to maintain the specific temperature the control is set for. Many ovens use a single oven burner and in this case they only have a single gas valve and ignitor. The same burner is used for both bake and broil functions.
On the high end models with separate bake and broil burners there will be an ignitor for each burner. They may also use dual gas valve instead of a separate valve for each burner. A model utilizing a dual gas valve, the internal construction of the valve allows the bake and boil functions to operate independently of each other. Each side of the dual gas valve should be looked at as two separate gas valves. As long as the ignitor is being powered, the control system or thermostat is operating fine. It should only take about a minute for the oven ignitor to reach the resistance that allows the proper current for the gas valve to open and the correct temperature for the gas to ignite. The ignitor, although glowing, may not be allowing the proper amount of current flow through it for the bimetal in the oven valve to open. It’s also possible for the oven burner to light and cycle a few times and then fail to ignite anymore, or take a very long time to ignite, and therefore fail to maintain the select temperature.
Proper testing of the ignitor requires an ohm meter to check for adequate current flow through the circuit to the oven valve. Another part that may malfunction is the safety valve itself. If the ignitor checks out OK, remove power from the range, remove the wires from the valve and perform a continuity test with an ohm meter. A working safety valve should read about 2-5 ohms. If open, replace the valve.
Now that you have a better idea of the problem and can identify what the solution could be, and what-if any- parts you need to repair or replace, go to PartSelect.com. There you can order your parts and find out more information about your specific repair.