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Why Is My Microwave Not Heating?

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A microwave, like any other electrical device, may fail, and it generally fails when you need it the most. In this post, we will attempt to assist you in diagnosing your microwave issue and determining why your microwave is not heating.

It is important to remember that you should never try to open the rear of a microwave oven if you are not a skilled electrical specialist. Even after the microwave has been disconnected for many hours, there remains a significant risk of electrical shock. Always delegate the repair to someone who is trained to work on microwaves.

Microwave Problems & Troubleshooting

Faulty Door Switch

Problem Microwaves often feature three to four door switches. When you shut the door, the switches engage and notify the microwave that it is safe to begin operation. If any of the three switches fails, the device will not function.

The light inside the microwave does not turn off when the door is closed, which is the most prevalent symptom of this issue.

Cause Slamming the microwave door, or for touch-based drawer microwaves, pushing the door closed, worn or malfunctioning components.

Repair & Maintenance It might be something as easy as a piece of plastic that has worn out or broken, or it could be an electrical problem that needs a professional specialist to diagnose and fix.

Microwave Power Failure Error

Problem Following a power outage, you may discover that your microwave displays PF or 8888 instead of the typical display. The PF stands for power failure, and the 8888 is likewise a power failure code.

Because the microwave’s power went off. This is common during power outages.

Repair & Maintenance This is a transitory problem for which you do not need to contact an expert. To get rid of the problem, just hit the CLEAR button. After you’ve fixed the problem, you may reset the time if you like.

A Faulty Capacitor

Problem You try to use your microwave, but it just creates a buzzing noise instead of cooking your food. It most likely has a faulty capacitor. A capacitor is an electrical storage device. A high-voltage capacitor is frequently important to the functioning of a microwave oven. If the capacitor fails, your oven will not function properly.

Cause Old and/or faulty parts.

Repair & Maintenance A qualified expert is needed to remove the capacitor and determine whether it is the root of the issue. If the capacitor is the source of the issue, it must be changed.

It is critical to remember that anybody working with the capacitor should first discharge it before testing. One of the most harmful components of a microwave is the capacitor. Even after the microwave has been switched off and disconnected, the capacitor may store enough power (like a battery) to kill someone.

Faulty Magnetron Switch

Problem The microwave looks to be operational, however it emits a buzzing sound when turning the food, and the food stays cold.

Cause Aged magnetron or faulty magnetron switch.

Repair & Maintenance The Magnetron is in charge of heating the food you place in the microwave. When in operation, the magnetron generates microwave frequencies by using high voltage electrical power. If either the magnetron or the switch is damaged, you must call a professional technician to replace it.

Faulty Thermoprotector

Problem Everything looks to be functioning well, but the food is not heating.

Cause Tripped fuse or faulty thermoprotector.

Repair & Maintenance Thermoprotector is a switch used to regulate the amount of heat in a microwave. When the temperature inside the unit surpasses a particular threshold, the gadget shuts off.

For obvious reasons, the microwave oven cannot function if this critical component fails. In certain circumstances, the device may have just tripped a fuse due to overheating and should be reset rather than replaced.

Dimming Microwave Light

Problem The light is weak at times and bright at others. It sometimes fades in and out.

Cause Microwave settings.

Repair & Maintenance Many microwaves may dim the illumination when used on lower power settings for operations such as defrosting or reheating. To put this to the test, microwave a cup of water on high for 30 seconds. Because it is working at full power, the microwave will light up properly. If the light is flickering, there is most likely a problem with the bulb.

Faulty Power Diode

Problem Although there is a buzzing noise during microwaving, the food continues to heat.

Cause Possible faulty power diode.

Repair & Maintenance A power diode is an electrical device that allows electricity to flow in just one way. The gadget transforms alternating current to direct current, thereby doubling the voltage to 5,000 volts. This power is then transferred to the magnetron, where it is converted to microwave energy. To test the diode, you will need to call a professional technician.

Faulty Triac

Problem Only at maximum power does the microwave cook food.

Cause Faulty controller switch.

Repair & Maintenance This issue may be resolved by a qualified technician.

Faulty Main Control Board

Although this is not a typical issue, the main control board might be faulty. If the control board malfunctions, you will be unable to input the necessary settings. As a result, you should talk with the dealer since it is most likely a manufacture flaw.

Microwave Repair Options

  1. If you bought your microwave lately, you may be able to return it to the retailer where you got it.
  2. If it is still under warranty, you may be able to get it fixed for free.
  3. If your microwave equipment is no longer under warranty, you will need to get it serviced by a local electrical specialist.

While we had planned to provide some do-it-yourself solutions, the severity of these microwave issues is better left to a specialist. With the price of microwaves these days, it may be wiser to buy a new one than hire a specialist to repair your old one.

Did you find this tutorial useful? Please share your microwave hacks and techniques in the comments.


How do you fix a microwave that is not heating?

How to Repair a Non-Heating Microwave
Step 1: Check the power supply of the microwave. Ensure that the microwave’s power source is hooked into a grounded, functional outlet.
Step 2: Check that the door is correctly shutting.
Step 3: Examine the microwave controls.
Step 4: Examine the error or display codes.

Why does my microwave run but not heat?

The most frequent cause of your microwave functioning but not cooking your food is a damaged magnetron. The magnetron is a critical component of a microwave that generates the microwaves required to heat your meal.

Can a fuse cause a microwave not to heat?

If the microwave is not heating, it is usually due to a faulty door lock or a blown fuse. If the problem is severe, a high-voltage capacitor, magnetron, or diode may need to be replaced.

What causes a microwave to suddenly stop working?

The primary fuse has blown, which is the most typical reason of a microwave not functioning. A power fluctuation or a faulty door switch may often cause the fuse to explode. It may potentially explode because another component, such as the magnetron or capacitor, is faulty.

Is it worth fixing a microwave?

Our poll findings indicate that you should try fixing the damaged microwave if it is still under warranty or if it is less than 5 years old, but you should absolutely replace it if it is more than 5 years old. There are additional options after you spend $500 or more on an OTR microwave.

How long should a microwave last?

A microwave may survive for 7 to 8 years with regular household usage and proper maintenance. If a single person or couple uses the microwave less often and maintains it properly, the lifetime may be extended to up to ten years.

What is the most common cause of microwave failure?

The magnetron is the most prevalent cause of microwave failure. The magnetron generates the microwaves that cook your food, yet it is also the most prone to failure. A malfunctioning or burned-out magnetron may cause a microwave to not heat food correctly or to stop working entirely.

How much does it cost to replace a microwave magnetron?

On average, replacing a microwave magnetron costs between $100 and $200. Because labor for changing the magnetron accounts for half of the cost, consider installing this replacement component yourself to save money.

Can a blown fuse cause no heat?

Wiring issues or blown fuses

Your car’s wiring, like your faulty HVAC controls, might be damaged or have a short in it. This would imply that the heating is not activated when the driver instructs it to do so.

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