Oven Shuts Off During Preheat? Here’s Why (+ How to Fix)

The best way to fix an oven that shuts off during preheat depends on the cause. It can be as simple as a clogged vent or as serious as a bad control board, sensor, heating element, safety valve, or limit switch (or thermal fuse). You can fix most of these problems on your own, though.

Here are 11 ways to fix an oven that shuts off during preheat, depending on the problem:

1. Check if the oven trips the circuit breaker.
2. Clean the oven vent and remove any obstruction.
3. Check the fans, depending on the type of oven.
4. Test the limit switch or thermal fuse.
5. Inspect the temperature sensor or thermostat.
6. Test the safety valve and replace it if it is broken.
7. Check the igniter in a gas oven and replace it.
8. Inspect the control board and replace it if it is bad.
9. Test an electric oven’s heating elements for continuity. 
10. Investigate a short circuit on an electric oven.
11. Verify and replace the heating element if damaged.

Also, the best fix for the problem depends on the type of oven (gas, electric, range, built-in, etc.) That means their specific components will vary, though their fundamental workings are the same. Keep reading to know the likely causes of and how to fix an oven that shuts off during preheat. 

1. Check if the Oven Trips the Circuit Breaker

There are a couple of signs an oven shuts off during preheat, such as:

• The oven stops working with or without an error code on the control panel display.
• The oven is not as hot as the set temperature. 

Some reasons an oven may shut off during preheat include:

• The convection fan stops working, and the oven stops preheating abruptly.
• The oven trips the circuit breaker during preheating, so you have to reset it.

Before you check for other problems, you should first verify if the circuit breaker is the issue. Here’s a checklist you can use:

• Check if the circuit breaker is functioning. A faulty breaker may trip, causing the appliance to shut off during preheat. 
• Confirm that you’re using the right voltage for the oven. Generally, gas ovens run on 110V / 120V, and electric variants require 220V / 240V. 
• Verify if you have an appropriate breaker for your oven. Electric ovens require a double-pole circuit breaker, rated for the required amperage (current). On the other hand, gas ovens use a single-pole circuit breaker.
• Check if the oven shuts off completely or if only the fan stops working. A convection fan doesn’t necessarily operate throughout the preheating time. In other words, a fan stopping for a while isn’t necessarily a cause of the oven turning off during preheat.

Doing these preliminary steps (plus checking the error code on the oven’s control panel display) can cut down the guesswork you have to do. Afterward, you can refer to the manual, interpret the error code, and choose the recommended solution. But if your oven doesn’t display error codes, you’ll have to take other steps.

2. Clean the Oven Vent and Remove Any Obstruction

Oven vents can accumulate greasy, grimy, and dusty buildup over time. When an oven becomes clogged with the aforementioned buildup, it can lead to overheating. This, in turn, causes the oven to shut off before preheating to the temperature you set.

Therefore, you may have to clean your oven vent to solve the problem. First, find where the vent of your oven is. Some gas ovens like GE have a vent at the center under the control panel. On the other hand, an electric oven may have a vent around the center or towards the rear, often under one of the surface elements. 

Clean the vent according to the manufacturer’s recommendations. For instance, GE suggests using soap or vinegar and water. You shouldn’t clean a gas oven with powders, abrasives, steel wool, and commercial cleaners.

3. Check the Fans, Depending on the Type of Oven

Convection ovens have at least one fan. Other ovens, like built-in and single-cavity models, have a cooling fan. These fans should work during preheat for the oven to function normally.

Like clogged vents, malfunctioning fans can cause overheating. 

Check the fan to confirm whether it’s working properly. Specifically, you should listen to how the fan sounds. A fan that’s in good shape should make a steady humming sound, rather than clicking, banging, or screeching noises. Also, watch out for failed starts and abrupt stopping of the convection fan motor. 

Fan issues don’t always require professional assistance. Sometimes, an oven fan may have a loose nut, blade, etc. All you have to do is tighten these parts, and the fan will work flawlessly. 

However, a fan motor can go bad, the bearings can fail, or the unit could be extensively worn-out. In this case, you have to replace the convection fan. 

If the convection fan is the issue, here are the general steps to replace it:

1. Turn the circuit breaker off, and unplug the oven from the power socket.
2. Inspect the convection fan inside the oven for signs of wear and tear or damage.
3. Spin the fan’s blade to test if it feels rigid or gets stuck somewhere. 
4. Tighten any loose nuts and check if the bearings work as you spin the blades.
5. Anything but an effortless spin means worn-out bearings or a bad motor.
6. On the rear panel of the oven, remove the screws and nuts. 
7. Take off the rear panel to check the motor of the convection fan. The motor may be damaged if it’s hot to the touch or looks burned. 
8. Remove the two wires connected to the motor’s terminals. 
9. Get a multimeter and test the resistance for these terminals. A reading of 20 to 90 Ohms indicates the motor is okay. Readings beyond 90 Ohms or zero resistance mean the motor is bad.
10. Match the part number to get an identical motor and replace the old one.

Your oven may have a cooling fan instead of a convection fan. Like the latter, this one can make loud noises or not work at all, resulting in the oven overheating and shutting off during preheat. 

Here’s how you can replace the cooling fan in a built-in oven:

4. Test the Limit Switch or Thermal Fuse

Electric ovens have a limit switch or thermal fuse as a safety feature. Also known as the high limit switch, this feature protects against electrical overloads. Interestingly, an oven’s limit switch can offer this protection to the heating elements alone or the entire oven. You’ll know this based on where the limit switch is within the oven’s circuit. 

Here are the two typical locations of a limit switch or thermal fuse:

• The limit switch is between the incoming hot wire and the heating elements.
• The switch or thermal fuse is between the incoming hot wire and the control panel.

In the latter scenario, a faulty limit switch will turn off the control panel of your oven. Therefore, if your oven shuts off and the display is blank, a defective limit switch may be the problem. 

The limit switch can fail or work intermittently. Your oven may start, stop, start again, and do other unusual things. 

Some limit switches reset on their own after you turn off the oven and restart in a few minutes. You can also manually reset the limit switch by pressing a button and letting it go as you hear a click signaling that the limit switch has been reset. 

However, you cannot reset a thermal fuse.

Here are the steps to test and fix a limit switch or thermal fuse on ovens:

1. Turn the circuit breaker off and unplug the oven.
2. Remove the rear panel to access the limit switch or thermal fuse.
3. Disconnect the wires from the two terminals of the switch or fuse.
4. Test the terminals with a multimeter. The reading should be between 0 and 1 Ohm. If there’s no resistance, reading, or beep on the multimeter, it means the switch or fuse is bad.
5. Replace the switch or fuse, whichever your oven has.

5. Inspect the Temperature Sensor or Thermostat

Some ovens don’t have a limit switch or thermal fuse, especially the gas ones. Gas and electric ovens that don’t have a limit switch use thermostats or temperature sensors to protect against electrical overloads. The thermostat or thermistor signals the control board to shut off the oven if it’s too hot.

Therefore, a bad or malfunctioning temperature sensor will not read the temperature on the oven correctly, turning it off during preheat. So, an inspection of the thermostat is in order.

You can check the temperature sensor for cracks, deformation, and other damage. Also, make sure the device is fitted snugly inside the oven. Finally, check if the wires of the temperature sensor are loose or snugly fit. 

Note that an oven temperature sensor can be faulty even if there’s no visible sign of damage. That’s because your oven may have a thermistor or a thermostat with a sensing bulb. These sensors usually have the same levels of resistance to different temperatures. 

In other words, a faulty thermostat can falsely detect a high temperature even when the oven isn’t that hot. The oven will then shut off. 

Here are the steps to test an oven’s thermistor or temperature sensor:

1. Find the thermistor in your oven, which is usually on the rear side. Older ovens with knobs in front may have a thermostat with a sensing bulb connected to the control panel.
2. Remove the nuts and screws to take out the temperature sensor. Disconnect the wires.
3. Take the thermistor out and test its resistance using a multimeter set to Ohms. 
4. A multimeter should read around 1,080 Ohms at room temperature. A reading between 1,000 and 1,200 Ohms is acceptable. Anything below or above that is worth a second look.
5. Replace the faulty thermistor. If you have a thermostat with a sensing bulb, you’ll need to replace the whole thing.

6. Test the Safety Valve and Replace It if It Is Broken

If your gas oven shuts off during preheat, you should test the safety valve for continuity. A gas oven can have one or two safety valves depending on the number of burners. Your oven could have one safety valve for the baking burner and another for the broiler function. 

The safety valve regulates the gas supply when the igniter is sufficiently hot. Therefore, a bad safety valve can close and disrupt gas flow into the oven, despite a glowing hot igniter. In effect, your oven won’t work in preheat. 

Like other components, safety valves don’t necessarily stop working completely. A valve may fail intermittently. Therefore, you should test the safety valve for continuity and replace it if the multimeter reads anything other than 1 to 5 Ohms.

To replace the safety valve on a gas oven like Frigidaire, watch the YouTube video below:

7. Check the Igniter in a Gas Oven and Replace It

A gas oven will shut down during preheat if the igniter isn’t glowing hot. A weak or damaged igniter doesn’t retain heat, causing the safety valve to close and shut the gas. You can check the igniter to see if it’s red hot as the gas oven preheats. Otherwise, let the igniter cool and check if it’s loose, sooty, cracked, or deformed. 

If the igniter is dirty but otherwise okay, you can just clean it with sandpaper. If it’s cracked, damaged, or deformed, you’ll need to replace it. 

Here’s a video on how you can replace a gas oven igniter:

8. Inspect the Control Board and Replace It if It Is Bad

If every component I’ve talked about works well and you’re still experiencing a preheating issue, you may have a bad control board. Generally, a failing control board is the most common reason ovens shut off during preheat. Therefore, you should inspect the control board.

Specifically, look for signs of damage. Check if anything looks burned. Inspect all the wiring harnesses and receptacles. Control boards have plenty of tiny circuits, relays, and similar features, so it can be difficult to tell whether everything is okay or just one element is kaput. 

That said, check the heating elements and whether the oven has a short. If anything is wrong with either, it may be time to replace the control board.

9. Test an Electric Oven’s Heating Elements for Continuity

Note that this step applies only to electric ovens. Checking whether there’s something wrong with an oven’s heating elements isn’t easy unless you can spot visible signs like cracks and burned portions. In this case, you should test the continuity of the heating elements. 

The good news is that you don’t have to remove the heating elements from the oven for the continuity test. To test an electric oven’s heating elements for continuity, follow these steps:

1. Ensure the oven is unplugged for your safety. 
2. Set the multimeter to the least resistance (Ohms).
3. Go to the rear panel and disconnect the wires from the heating element terminals.
4. Place the multimeter probes on the terminals and check the reading. A reading between 30 to ~100 Ohms implies the heating element has continuity. Otherwise, the heating element is damaged, and your oven may be at risk of a short. 

10. Investigate a Short Circuit on an Electric Oven

Again, this only applies to electric ovens. If you suspect a short in your oven after taking the steps in Item No. 9, here’s how you can check if that’s the issue:

1. Keep the oven unplugged, and the rear panel removed. 
2. Set the multimeter to over 1,000 Ohms.
3. Connect one probe of the multimeter with a terminal of the heating element.
4. Take the other probe of the multimeter and touch the bare metal body of the oven.
5. If the multimeter detects continuity, the oven has a short due to the heating element.

11. Verify and Replace the Heating Element if Damaged

A damaged heating element can also cause a short. Further, broken or malfunctioning heating elements may keep cycling on and off, effectively shutting and restarting the oven. In this case, you should not use an electric oven for the sake of your safety. 

Some ovens have more than one heating element. If you have one of those ovens, inspect each element’s condition. Fortunately, replacing the heating element is easier than it sounds. 

Here’s how you can install a new heating element in an electric oven:

Key Takeaways

Whenever an oven shuts off during preheat, rule out the obvious problems first. To do so, you should:

1. Check the circuit breaker, clean the vents, and test the fans to fix them.
2. Replace the limit switch or temperature sensor, whichever is faulty.
3. Test and replace a bad safety valve. 
4. Clean the igniter or replace it if necessary.
5. Investigate the control board and get a new one if necessary.
6. Replace damaged heating elements. Do not operate a shorted oven. 

If you are wondering if you can leave your oven on overnight, the answer is yes, but it is never recommended, especially if you leave it unattended. Leaving an oven on overnight is dangerous if you’re asleep and no one watches it. No one will be able to prevent any risk or danger from happening. 

Finally, if your meal needs to be prepared for over 12 hours, never leave it unsupervised. Every oven, whether electric or gas, may be left open if you watch what you’re cooking. To prevent any risk or danger, turn your ovens off after any dish is ready to serve. 

Steve Rajeckas

Steve Rajeckas is an HVAC hobbyist with an avid interest in learning innovative ways to keep rooms, buildings, and everything else at the optimal temperature. When he’s not working on new posts for Temperature Master, he can be found reading books or exploring the outdoors.