Why Won’t My Gas Oven Heat Up?

An ignition failure in a gas oven is one of the top appliance failures that appliance repair technicians face. One of these common problems can prevent the oven from igniting:

• Lack of an adequate gas supply.
• Bad igniter.
• Wiring failure.
• Defective electronic control board.
• Failed safety gas valve.

Your best bet on getting this type of failure fixed quickly is to schedule a Sears Technician to visit your home and fix the oven.

For advanced DIY appliance repair enthusiasts, we recommend that you view our troubleshooting video below to help you figure out what’s wrong with your oven and fix it.

Here’s a written narrative of the troubleshooting shown in the video.

Check the Stove's Gas Supply

First, verify that you have an adequate gas supply provided to the range by starting a surface burner and see if it lights up. If it does, then you know that the gas supply to the range is good.

If the burner isn't getting gas, check your gas supply cut-off valve to make sure that it's open. If the gas supply valve is open, then you'll need to contact your gas supplier to restore the gas supply to the range.

Some ranges have a service cut-off valve on the pressure regulator that shuts off the gas supply to the oven and not the surface burners. If your range has one, make sure that the service valve is open.

Check the Oven Burner Igniter

Next, check the oven burner igniter.

Before testing the igniter, you'll need to know how the ignition system works so that you can understand how to test it.

This range uses a glow bar igniter and safety gas valve to light the oven burner. These components are wired in a series type of electrical circuit. They work together to light the oven burner.

When you start the oven, the electronic control sends current to the igniter. Current travels through the igniter first and then the current goes through the safety gas valve since the components are wired in series. When the igniter is cold, it has high resistance, restricting the current flow going to the gas valve. The igniter is using up all the current to heat from the cold start. The gas valve won't open yet because it's only getting scant current as the igniter heats. As the igniter heats up, its resistance goes down and more current flows to the gas valve. The igniter continues to heat until it reaches ignition temperature. At ignition temperature, igniter resistance is so low that current flows freely to the safety gas valve. The strong current flow heats up the bi-metal disc inside the safety gas valve. The bi-metal disc warps due to the heat and snaps open the gas valve, allowing gas to flow to the burner. The hot igniter lights the gas and your oven heats up.

So why the long explanation? Because the most frequent failure of this ignition system is the igniter. The igniter may heat and glow and lead you to think that it's okay, but if it doesn't heat all the way up to ignition temperature, then the gas valve won't open and your oven won't heat.

Now, pull the bottom panel out and see if that igniter glows when you start the oven.

When the igniter glows, you know that all the components in the ignition circuit have continuity. The ignition circuit includes the electronic control, the wiring, the igniter and the safety gas valve.

When you see the igniter glowing and the oven not lighting, you can suspect that the igniter is not heating enough to allow current to flow freely to the safety gas valve.

In this situation, you'll probably need to replace the igniter even though it glows. This may not have made sense to you without the explanation of how the ignition system works.

To verify this diagnosis, you can use a multi-meter with an ammeter clamp.

Set your meter to measure amperage. Clamp the ammeter around one wire in the ignition system.

Start the oven and monitor the amp draw. When the amperage exceeds 3.2, the safety gas valve snaps open and the burner ignites.

If you start the oven and the amperage never reaches 3.2, then you'll need to replace the igniter.

This oven uses a square igniter. Some ovens use a round igniter. The ignition threshold for the round igniter is 2.8 amps instead of 3.2 amps.

Check the Other Oven Ignition Components

So – what if the igniter doesn't glow?

If the igniter doesn't glow, then one of the components in the ignition system is broken.

Use your multi-meter to check the wiring, igniter and safety gas valve for continuity.

First, unplug the range to disconnect electrical power.

Pull the range forward and remove the back panel to access the electronic control board.

Unplug the yellow wire from the Bake spade and the white wire from the Neutral spade on the control board. Measure the resistance through the yellow and white wires. You should measure between 10 and 2000 ohms through those wires. If so, then you'll likely need to replace the electronic control board because the all of the other components in the circuit are okay.

If you measure an open load through the yellow and white wire, then you have a bad igniter, a failed safety gas valve or a break in the wiring.

Check the resistance directly at the igniter. You should measure between 10 and 2000 ohms through the igniter. If you measure an open load through the igniter, replace it.

If the igniter is okay, check the safety gas valve. You should measure about 1 ohm or resistance through the safety gas valve. If you measure open load, replace the safety gas valve.

If the safety gas valve and igniter are both okay, then you'll need to find the break in the wiring. Measure the resistance in the yellow wire between the electronic control board and the igniter. Next, check the resistance in the white wire between the igniter and the safety gas valve. Then check the resistance through the white wire between the safety gas valve and the electronic control board. You should measure near zero ohms of resistance through those sections of wiring. If you measure an open load in a section of wiring, repair or replace the wire.

These troubleshooting tips should help you figure out what’s wrong with your gas oven when the burner won’t ignite.

If you get to a point where you’re not completely confident that you can conduct the troubleshooting described or you can find the cause of the ignition problem on your own, schedule a repair call and we’ll send a Sears Technician right out to your home.

To prevent oven heating problems and keep your range in top shape, have a Sears Technician perform an annual Clean & Maintain service on your range. The service tech will check your range and oven for proper functioning, wear and tear, gas leaks and clean internal components. Having your stove professionally maintained and cleaned yearly will also extend the life of your range and help keep you safe.