The first step in diagnosing a pilot light problem with your oven is to make sure the oven even has a pilot. Most ovens have a glow bar ignition system, which functions like a pilot, but is prone to different problems. If the ignition system of your oven does include a pilot, it probably also includes a spark igniter to light it so that it doesn't have to stay on and waste gas. Some oven manufacturers bypass the need for a pilot altogether by devising systems whereby an electronic spark directly ignites the gas.
Open the oven and expose the pilot and burner assembly by removing the cover plate and flame spreader, if there is one. If the oven has a pilot light, you will see a gas tube that may or may not have a small blue flame burning at its end. If the oven has a glow bar, however, you'll see an insulated electronic device centered in the burner. Consult an appliance repair person to service a glow bar.
Determine if the oven has a spark igniter by turning on the thermostat. You'll hear a clicking sound and see a spark in front of the pilot tube if there is one.
Make sure the gas is on before proceeding. Clean the tip of the pilot tube with a needle and try lighting it. If there is no spark igniter, hold in the thermostat knob while you light the pilot with a match. Keep the knob in for about a minute after the pilot lights. If there is a spark igniter, simply turn the thermostat on and off repeatedly until the pilot lights.
Observe the flame. It should be mostly blue and about an inch high. If it is orange or sputters, turn off the gas, unscrew the pilot tube with a wrench and clean it with compressed air.
Start the pilot again and turn up the thermostat. The pilot flame should widen, but it usually takes a minute or two for the flame to spread to the burner. The reason for this is that the thermocouple, which prevents gas from flowing when the oven is off, must heat up to a prescribed temperature before it sends an electric signal to the gas valve instructing it to open. The thermocouple or gas valve may be faulty if the burner doesn't ignite.
Replace the thermocouple by unscrewing it from the gas valve with a wrench and unhooking the tip from the clip that holds it next to the pilot. Hook on the new one, screw it to the gas valve and try the oven. Replace the gas valve if the problem persists.
Replace the spark igniter if it doesn't produce a spark when you turn on the oven. This may involve disconnecting some electrical wires, so have the oven manual handy.
- Can of compressed air
- Some ovens have a flame switch instead of a thermocouple. It functions in the same way, but it has electrical connections to both the thermostat and the gas valve. You must remove both connections to replace it.
- A dangerous situation can develop if your oven has a glow bar igniter instead of a pilot. As the igniter ages, it can fail to reach its normal operating temperature. Gas can then build up in the oven, and when it finally ignites, it can do so with explosive force. If this happens, stop using the oven until you replace the igniter.