Oven Not Heating

An oven's temperature sensor monitors the temperature inside the oven cavity in order to maintain an accurate temperature. If the temperature sensor is faulty, the oven may not heat at all. The sensor can be tested for a proper ohm reading at a set temperature with a multimeter to help determine if the part is defective or not.

For bake & broil burner ignition an oven burner spark electrode is used to ignite the gas. The electrode is a device that sits right next to the burner. It functions like a spark plug. As power is applied to it a spark jumps from the spark electrode tip to the to the electrode shield, igniting the gas. If the electrode is broken or worn out the spark may not occur. Visually inspect the electrode assembly for cracks in the porcelain housing or damage to the electrode tip itself. Be aware that a proper ground and the correct polarity of the incoming voltage to the range is necessary for the electrode control to sense the presence of a flame once the burner is ignited. If the burner goes off after ignition check for proper ground and the correct polarity at the wall outlet.

Inspect the broil element for holes or blisters. When the broil element is heating properly, it glows red hot. If the element does not glow red, this indicates that the element is not heating. Often, if the broil element has burned out, it will be visibly damaged. To determine if the broil element has burned out, use a multimeter to test the element for continuity. If the broil element does not have continuity, replace it.

For gas ovens using a spark igniter, a faulty spark module could be responsible for the oven not heating. If you do not see a spark near the bake or broiler burner tube when the oven is turned on, use a multimeter to determine if voltage is reaching the spark module. If power is present, the spark module is likely defective and will need to be replaced.

Electric ovens require 240 volts of alternating current. Gas ovens require 120 volts. If an oven won't turn on there could be an incoming power problem. To determine if the electrical outlet is providing sufficient voltage, use a multimeter to test the incoming power at the wall socket.

If the oven gets too hot, the thermal fuse trips to shut off power to the oven. If the thermal fuse has blown, the oven will not heat. However, this is not a common occurrence. To determine if the thermal fuse is at fault, use a multimeter to test the fuse for continuity. If the thermal fuse does not have continuity, replace it. The thermal fuse cannot be reset—if the fuse has blown, it must be replaced.

One of the wires that supply power to the oven element or igniter might be burnt out. These wires commonly burn out near the heat source. To determine if a wire has burned out, inspect the wires leading to the element or igniter. If a wire is burned out, it will often be visibly burnt.

Some ovens are equipped with a relay board. The relay board has several relays which control the electrical current to the heating element. If one or more of the relays on the relay board has failed, the oven won’t heat. If the relay board is defective, replace it.

The oven control board has relays that send voltage to the bake and broil circuits according to the user settings and sensor input. If the control board is defective, it may not send voltage to the heating components. However, this is rarely the case. Before replacing the control board, first test all of the heating components. If you determine that all of the heating components are working properly, replace the oven control board. Since it’s not easy to test the oven control board, you will have to replace the control board if you suspect it is defective.

The gas oven safety valve works with the oven igniter to provide gas to the burner. If the safety valve fails, the oven won’t heat. However, this is rarely the cause. Before replacing the safety valve, first test all of the more commonly defective oven components, particularly the igniter. If all of the other heating components are working properly, use a multimeter to test the safety valve for continuity. If the safety valve does not have continuity, replace it.

The oven thermostat regulates the broiler temperature. If there is an oven broiler problem the oven thermostat might be defective. The oven thermostat has a thin copper tube attached to a slightly thicker tube which sticks into the oven. Inside this tube is a type of hydraulic fluid. As the broiler temperature rises the fluid expands which puts pressure on a small activator inside the thermostat and shuts off the heat. As the broiler cools, the pressure reduces and the activator allows the broiler to heat. The oven thermostat is difficult to test and is not repairable. If this is the cause of the problem the oven thermostat will have to be replaced.