Microwave Overheated And Won’t Turn On? Here’s How To Fix It

Categorized as Microwave Repair and Troubleshooting
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Microwaves are essential kitchen appliances that allow us to quickly heat up or cook food. However, like any appliance, they can run into problems. One common issue many microwave owners face is the microwave overheating and refusing to turn back on.

This can be frustrating, especially if you rely on your microwave daily. But there’s no need to panic or rush out to buy a new one just yet. In most cases, this issue can be easily fixed with a few troubleshooting steps.

In this comprehensive guide, we’ll cover:

  • Common reasons for microwave overheating
  • Step-by-step instructions to get your overheated microwave working again
  • Tips to prevent overheating issues in the future
  • FAQs on microwave overheating

What Causes A Microwave To Overheat?

Before diving into solutions, let’s first understand what causes a microwave to get so hot that it shuts itself down. Here are some of the most common culprits:

Blocked Vents

Microwaves require proper ventilation to prevent internal heat buildup. If the exterior vents become covered or blocked by debris, the trapped heat can trigger the internal safety mechanisms, causing the microwave to shut off.

Faulty Door Seals

The door seal ensures microwaves stay contained inside when cooking. If this seal is damaged or deteriorating, heat and microwave energy can leak out. This not only leads to uneven cooking but can also overwork the microwave and cause overheating.

Broken Fan

Most microwaves have an internal cooling fan that circulates air to regulate temperature inside. If this fan malfunctions, heat gets trapped, leading to the microwave shutting itself down temporarily.

Failed Thermal Fuse

A thermal fuse will blow to shut off power if the microwave overheats dangerously. If your microwave’s fuse keeps tripping, it likely has an underlying issue causing chronic overheating.

Excessive Use

Using the microwave continuously for long periods, especially at high power, can overwhelm the internal components and cause overheating.

Damaged Or Faulty Components

Problems with key components like the magnetron, high voltage diode or transformer can disrupt normal functioning and heat circulation, leading to overheating.

Now that we know why microwaves overheat, let’s look at how to get an overheated unit working again.

How To Fix An Overheated Microwave That Won’t Turn On

Follow these troubleshooting steps in sequence to get your overheated microwave back up and running.

Step 1: Unplug The Microwave

As soon as you notice the microwave is overheated and not turning on, unplug it from the power source. This cuts power to the device and allows the internal components to start cooling.

Do not attempt to use the microwave until it has had time to cool down. This is critical, as you do not want to risk damaging already overheated parts.

Wait at least 30 minutes before moving to the next step. This gives time for any tripped thermal switches to reset.

Step 2: Check And Clear The Vents

Carefully inspect the external vents at the back or sides of the microwave. See if any are blocked by dust, grease or debris.

Use a vacuum with a brush attachment to gently clear any obstructions. Compressed air can also help dislodge stubborn dirt and lint buildup.

The vents must be completely unobstructed for proper airflow and cooling inside the appliance.

Step 3: Inspect The Door Seals

Examine the rubber seal around the microwave door. Check for any signs of deterioration, cracks, or melting.

Look to see if the door sits squarely when closed. Misaligned seals prevent a tight door closure, allowing heat leaks.

If the seals are damaged in any way, they will need replacement. Contact the manufacturer or authorized service center to source the correct replacement seal kit.

Step 4: Check Internal Components

This step requires opening up the microwave interior and should only be done with the power disconnected.

Look for any obvious problems like burnt or damaged wires, blocked fan blades, or cracks in critical parts like the magnetron.

Unless you are familiar with microwave repair, it’s best to have a professional technician inspect and diagnose any internal faults. Internal components should only be handled by someone qualified.

Step 5: Reset The Microwave

Check your owner’s manual on how to perform a hard reset for your specific microwave model.

On many microwaves, holding down the cancel button for 3 seconds resets the control panel. Refer to manual instructions.

Resetting your microwave will clear any fault codes and reset safety features tripped during overheating.

Step 6: Test Operation

Plug the microwave back in and try running it empty for 1 minute at medium power. Ensure the turntable rotates smoothly.

Listen for any abnormal noises like buzzing or humming. The microwave should run quietly.

If it does not turn on or trips any breakers, overheating issues are still present. You’ll need to repeat the above steps.

Do not attempt to run a microwave you suspect is still overheating.

If troubleshooting does not restore normal operation, the unit likely needs professional servicing or replacement.

Tips To Prevent Microwave Overheating

Once you get your overheated microwave working again, keep it running safely with these tips:

  • Allow adequate ventilation – Don’t cram the microwave in tight spaces. Leave at least 3 inches clearance on all sides. Keep the top vent unobstructed.
  • Use microwave-safe cookware – Damage or faults in containers used inside the microwave can lead to arcing and overheating.
  • Keep it clean – Regularly wipe down the interior and exterior, especially the door seals. Remove food splatter right after use.
  • Don’t block the fan – Ensure nothing is placed near the fan opening that could obstruct airflow.
  • Follow recommended cook times – Don’t overcook food past the suggested times for your microwave wattage.
  • Don’t run it empty – The microwaves need something to absorb the energy. Without food or liquid inside, it can overheat quickly.
  • Have it serviced yearly – Annual servicing by a technician can detect and resolve minor issues before they become big problems.

FAQs About Microwave Overheating

Got questions about dealing with an overheated microwave? Here are answers to some frequently asked questions.

What are the most common reasons a microwave overheats?

The most common reasons are blocked vents, faulty door seals, broken cooling fans, damaged internal components, and excessive continuous use especially at high power.

Why does my microwave shut itself off when it overheats?

This safety feature shuts the microwave down to prevent permanent damage to its internal parts which can be fragile. Allowing it to run while overheated risks serious damage.

How long should you wait before using an overheated microwave?

Wait at least 30 minutes after unplugging to allow the appliance to cool completely. This gives internal components time to reset and return to normal temperatures.

What happens if you keep using an overheated microwave?

Continuing to use an overheated microwave that hasn’t been allowed to properly cool risks causing severe, permanent damage like melting wiring, cracking magnetron tubes and short circuiting.

Does overheating damage a microwave permanently?

Not necessarily. If promptly unplugged and allowed to cool, most overheated microwaves can return to normal function after troubleshooting. But chronic, repeated overheating can definitely shorten its lifespan.

Should you repair or replace an overheating microwave?

For older microwaves, repair costs likely exceed the value of the appliance. But for newer units just outside the warranty period, repair may be worthwhile before replacing the entire unit.

Can I prevent my new microwave from overheating?

Yes! Follow the overheating prevention tips outlined above. Key steps are providing adequate ventilation, keeping vents/filters clean, using microwave-safe cookware, and not overcooking.

In Closing

We hope this guide gives you a detailed overview on how to get your overheated microwave working again. The most important first step is always to unplug it and allow sufficient time for it to cool completely before attempting troubleshooting.

Prevention is also key to avoid recurring overheating issues through proper usage and maintenance. With some diligent care and attention, your microwave should give you many years of reliable service.

By Rosie Elliott

I’m Rosie. I’m a professional chef with experience in Western, Mediterranean, and Italian cuisine. I’ve been cooking for over 15 years, and I have two daughters that keep me busy!

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