Microwave Not Heating – Reasons and Solutions

Microwave Not Heating

Microwaves are a convenient and essential appliance in many homes. However, when they stop heating, it can be a frustrating inconvenience. This article will explore the common reasons why a microwave may not be heating and provide solutions to fix the problem.

Whether a blown fuse or a malfunctioning door switch, we will help you troubleshoot and repair your microwave so you can enjoy your favorite warm meals and snacks. So, if you have a Microwave that is not heating, this article will guide you through figuring out the problem and fixing it.

Key Takeaways: 

  • Try switching the microwave on and off. Also, check if the cable is connected to the socket.
  • Check if the door is closed correctly since a microwave won’t function when the door is open.
  • Inspect the cord to see if there are any visible wires. A damaged cable means not enough electric current going through.
  • If all these solutions don’t work, it’s time to call a technician and have them inspect the device. Trying to tamper with a microwave is unwise as you risk further damage.

Why Is My Microwave Running but Not Heating Up?

It’s frustrating to try warming your food only for the microwave to stop heating up. In most cases, you’ll notice the device is running as usual, but it’s not heating the food. It’s often a sign that one of the internal components isn’t working or there’s something you’re doing wrong. 

Here are a few reasons why your microwave might be behaving this way:

  • A faulty door switch
  • A blown fuse
  • A malfunctioning diode
  • A defective control board
  • A faulty magnetron or transformer

A Faulty Door Switch

A faulty door switch in a microwave can prevent the appliance from heating properly. The door switch is a safety mechanism that prevents the microwave from operating when the door is open. If the door switch is faulty, it can prevent the microwave from turning on or cause it to turn off unexpectedly during use.

Also, not locking the door properly could prevent the microwave from heating. Double-check if the door is closed properly before powering the microwave on.

If your Samsung microwave is not heating food but runs, see how you can fix the faulty door switch.


A Blown Fuse

The fuse is a safety device designed to protect the microwave from electrical overloads. If the fuse is blown, it will interrupt the flow of electricity to the microwave, causing it to stop functioning.

If you suspect your microwave’s fuse is blown, you must unplug the appliance and check the fuse to see if it needs to be replaced. If your LG microwave is not heating food but runs, watch how you can replace the blown fuse.

If you are uncomfortable doing this yourself, it’s best to let a qualified technician repair the fuse.


A Malfunctioning Diode

The diode is an electronic component that converts alternating current (AC) to the microwave’s direct current (DC). If the diode is malfunctioning, it can prevent the microwave from generating the high-voltage AC power needed to produce heat. However, the device will remain functional and turn on as usual but will not heat the food.

You’ll detect an electric burning smell when the diode starts to malfunction. Unfortunately, many people conclude it’s a blown fuse when this happens.

Watch how you can test the diode if your Kenwood microwave is not heating.


A Defective Control Board

The control board is the “brain” of the microwave and controls all the appliance’s functions. If the control board is defective, it can prevent the microwave from turning on or cause it to turn off unexpectedly during use.

Several signs can indicate a defective control board in a microwave. Some of the most common signs include: 

  • The microwave not turning on
  • Display not working
  • The microwave turning off unexpectedly
  • Buttons not responding properly.
  • Strange noises from the microwave
  • Turntable not turning
  • The light is not working.

See how you can test for a defective control board if your Breville microwave is not heating.


A Faulty Magnetron or Transformer

The magnetron is the part of the microwave that generates the microwaves that cook the food. If it is broken, the microwave will not heat up. That is a severe problem that requires a repair technician’s help.

The transformer is an electronic component that converts the low-voltage AC power from the outlet into the high-voltage AC power needed by the magnetron.

If either of these components is faulty, it can prevent the microwave from generating the heat needed to cook the food.

One significant sign of a faulty magnetron or transformer is when the microwave is not heating, but the timer is working.

If your Whirlpool microwave is not heating, watch this video to learn how to test for a faulty Magnetron.

How Do You Fix a Microwave That Is Not Heating?

To fix the microwave that is not heating, you must determine the problem first. In most cases, switching the appliance off, unplugging it, and letting it rest for a while solves minor issues. 

However, some problems require practical approaches, and here are some steps you can take to solve the issues. 

  • Check the cable for signs of wear and tear.
  • Check if the cable is properly attached to the socket
  • Confirm if you have a sufficient power supply
  • Check the door switch to confirm it’s not faulty or stuck

Check the Cable for Signs of Wear and Tear

When troubleshooting a microwave that is not heating, you can check the cable for signs of wear and tear. If the cable is damaged, it can prevent the microwave from receiving the electrical power needed. 

To check the cable, unplug the microwave and carefully inspect it for any signs of damage, such as fraying or exposed wires.

If you notice any damage, it is recommended that you replace the cable with a new one. That will help ensure that the microwave has a stable and reliable power supply, which is essential for proper operation.

Check if the Cable is Properly Attached to the Socket

A loose cable could be another reason your microwave is not heating as needed. Ensure you check if it’s attached firmly to the socket before powering on your appliance.

Confirm if You Have Sufficient Power Supply

Microwaves require a minimum of 120 volts to function correctly. However, there might be a problem with your power supply, reducing the voltage reaching the microwave. So you need to:

  • Plug the power cord into a nearby outlet and turn on the microwave.
  • Observe the microwave as it is running.

If the microwave functions correctly, with the turntable rotating and the light turning on, it will likely receive sufficient power.

If the microwave does not turn on or seems to be malfunctioning, there may be an issue with the power supply. In this case, it is best to consult the owner’s manual or a qualified repair person.

Check the Door Switch to Confirm It’s Not Faulty or Stuck

A microwave door switch activates the appliance when closed, and only then does the device start heating. However, try taking these steps if you suspect the door switch is faulty or stuck.

  • Switch off the microwave and open the door to inspect the switch. A small button or lever on the door frame inside activates when the door is closed.
  • Press or move the door switch to ensure it is functioning correctly. The door switch should move freely and activate when the door is closed.

If the door switch is stuck or does not activate when the door is closed, it may be faulty. In this case, it is best to consult the owner’s manual or a qualified repair person.

Bottom Line

A microwave running but not heating indicates internal components are not working. Check the door switch, and replace the fuse, diode, magnetron, or transformer if faulty. If you’re unsure or uncomfortable doing all this, ensure you hire a technician to handle all the troubleshooting or repair tasks.

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