Troubleshooting a Gas Oven That Won't Heat Up

If you turn on your gas oven and it doesn't heat up, there are several possible causes, and you may be able to remedy the problem yourself, without calling a repair service.

1. Check the Circuit Breaker

If you are lucky, the problem may simply be that the electrical circuit supplying power to the oven has tripped a circuit breaker. Even though the oven heats with gas, it requires electrical power to operate the timer and other components, and if the circuit breaker has tripped, the oven will refuse to heat.

Since this is a gas oven, it will be connected to a circuit with a standard 15- or 20-amp breaker, not a large double-pole (usually 50-amp) breaker such as those used by electric ovens. Your oven may have its own breaker, or it may be tied into one of the small appliance or kitchen receptacle (outlet) circuits with a common breaker. If the breaker serving the oven has not tripped, the next thing to check is the gas supply and igniter. 

2. Check the Gas Supply

Although rare, it is possible that your supply of natural gas or liquid propane gas has been interrupted for some reason. This usually happens when the main gas valve has been shut off to make some repair or replacement in the system and hasn't been turned on again. Check the main gas valve, as well as any valves located on branch lines, to make sure they are in the ON position. If your oven has just been repaired or replaced, it's also possible that the gas valve on the supply pipe hasn't been turned back on. If the gas supply checks out to be fine, then turn to the gas igniter on the oven itself.

3. Check the Igniter

The problem could be that your oven igniter has simply gone bad. In normal operation, when the oven control is turned to bake, the igniter turns on and starts to glow bright orange. After the igniter gets hot, the gas valve opens and sends gas through the burner. The igniter lights the gas coming from the burner and the oven begins to heat.

If, however, the igniter doesn't glow hot enough, the oven will not light, and you'll likely smell a little gas. Don't worry though; the gas valve is equipped with a safety mechanism that shuts off the gas if the igniter isn't working properly.

1. To check the igniter, turn off the circuit breaker to the oven, then confirm the power is off by making sure the oven light, clock, and any other electrical functions are not working.
2. Remove the oven racks and the large metal plate (there may be more than one) at the bottom of the oven. This should expose the gas burner and igniter.
3. Inspect the igniter for discoloration on the coil or element that is different from the rest of the igniter. This is sometimes a sign of a failed or failing igniter.
4. If the igniter looks okay, you can turn the power back, set the oven to heat, and observe the igniter at the beginning of the heating cycle. It should glow a bright orange within a few seconds. If it does not, and the gas does not ignite quickly, turn off the oven to stop the ignition function. The igniter has failed the test and will need to be replaced.
   

4. Check the Temperature Sensor

It may be that the temperature sensor for your oven's thermostat is not functioning correctly. This measures the heat levels inside the oven. Temperature control is connected to the sensor and when the resistance in the sensor changes the temperature control turns the heating element on and off. If it's not detecting the temperature accurately, several problems can occur including uneven temperature throughout the oven and faulty temperature readings.

Try checking the temperature sensor with the following method:

1. Unplug the oven.
2. Find the thermostat and remove it from the oven.
3. Test the thermostat using a multimeter, set to measure resistance and turned to the lowest ohm rating.
4. Place the multimeter on the thermostat.
5. Read the thermostat. If the reading on the scale is zero or close to zero then the temperature sensor is working. If the multimeter shows no reading, the sensor is bad.
   

5. Check the Oven Safety Valve

If your oven won't heat up, another possibility is the failure of the safety valve or gas valve. This part guarantees that gas only comes to the oven when the igniter is hot enough to light up the gas. Using a multimeter you can test for a break in the electrical flow at the valve.

1. Shut off the power supply to the oven.
2. Disconnect the safety valve wires from the terminals.
3. Touch one probe of the multimeter to one terminal and the other probe to touch the other terminal.
4. Check the multimeter for a reading between 0 and 5 ohms. This means the safety valve is working.
5. Check the multimeter for a still needle or no significant change in a digital reading. This means the valve is defective and will need replacement.
   

Replacing the Igniter

It's easy enough to replace an oven igniter if you understand the process.

1. Before you can replace the igniter, you'll have to order a replacement for the defective one. Not all igniters are the same. In fact, they are pretty much all different and have different electrical connections. The only way to get the right replacement part is to start with the oven's model number and serial number. This may be on the back of the unit, inside the door or drawer, or even on a card or tab that slides out from behind the control panel of the oven. With your model and serial numbers in hand, you can search online for a replacement part, or call or visit a local appliance parts supplier. You can also contact the oven manufacturer online or by phone.
2. Shut off the power before doing any work on the oven, and be careful not to touch the igniter coil. Sometimes, these are black-colored spring-like coils; other times they are flat prong-like loops extending from the base of the igniter. The coil is very fragile, and oil from your hands getting on it can shorten the lifespan of the igniter. 
3. Remove and replace the gas igniter, following the instructions included with the new igniter. It is an easy job, requiring only screwdrivers, a circuit tester, and a replacement igniter.

Replacing the Temperature Control Thermostat

If the igniter is not the issue, try replacing the temperature control thermostat. This is a job that can be tackled by the homeowner with the right steps.

1. Turn off the power supply to the oven at the circuit breaker.
2. Remove the back panel or open the control panel and locate the thermostat.
3. Remove screws holding the thermostat in place and disconnect it. Pull it out gently.
4. Position the new thermostat in the same place.
5. Secure it with the same screws and connect the wires as recommended by the manufacturer.
6. Turn the power supply on and test the new thermostat.
7. Reassemble the back panel or control panel cover.

When To Call a Professional

Although there are many things you can do as the homeowner to troubleshoot what is going on with your gas oven, it's always a safe idea to call a professional to repair it. If you suspect any kind of gas leak associated with your oven, you should seek expert help immediately as these can lead to fire and health hazards.