May 9

Why is My Microwave Not Heating Up? – 4 Solutions


Author: Gisele Perez and its partners may earn a commission if you purchase a product through one of our links.

It’s quite easy to get really worried when you discover that your microwave is not heating up. If you do not have alternatives, this can get really worrisome.

The most likely reason why your microwave is not heating up is either the Magnetron is damaged or the components that POWER the Magnetron are damaged. Magnetron Assembly is the device that generates microwave heat.

So if you are sitting there and wondering why is my microwave not heating up, then the short guide here will help.

In this article, we will consider the various other reasons why your microwave might not be heating up. Most of these will require professional help.

However, if you are a handy person yourself and are knowledgeable about handling electronic repairs, you might not even have to spend money on a technician with our ‘ How to Repair Microwave Oven Not Heating‘ post.

Also Read:

 Why is My Microwave not Heating Up

There are simpler as well as more complicated explanations. Let us start with simpler ones first.

1. Your Microwave Door is Faulty

Most people don’t understand how important doors are in all oven types. They help trap heat and ensure the proper working of your electronics.

So if your microwave oven (see here how microwave ovens cook) is refusing to heat up, it might be that the door is faulty.

If you suspect your microwave door is damaged or is leaking heat, cease operating it immediately. Do not attempt any repair on them since they are specialized doors made to block microwave heat from escaping.

How to Check

Why is My Microwave Not Heating Up
Heat leaks from doors are rare but possible. Read: Ways to check a microwave for leak

Fortunately, this is quite easy to check. There is a likelihood that your microwave would have been giving warning signs through the hinges before the door decides to stop functioning.

Although oven doors hardly malfunction with microwave ovens, it is not totally impossible.

Simply check if the microwave oven door is opening and closing properly. If not, you might need to change your microwave oven door or hinge. It is better to take advice from a handyman.

If you suspect a leak, you can use a bulb that reacts to microwave or professional testing equipment to check. A straight fluorescent light bulb can be used in absence of professional equipment.

2. If the Door Switch is Faulty

If your microwave oven does not start to heat AT ALL, then a door switch should be the first culprit you need to investigate.

Microwave ovens are designed in a way that if the door switch is not engaged, the microwave control panel will prevent you from switching it on.

This is for your own safety.

How to check

Test the switch, you can use the multimeter. I recommend that you keep one home with you at all times. If you discover that it isn’t working perfectly, you might have to replace it with a new one.

3. Malfunctioning Power Component

Microwave oven repairing
Check for internal power components

If your microwave isn’t heating up without any prior probable reason, you might want to consider that there is a damaged power component.

There are four main culprits here

  • Fuse
  • Transformer
  • Capacitor
  • High Voltage Diode

The fuse is a protection device. If your oven isn’t turning on at all, it is worth checking out the fuse. The fuse blows up if it experiences short circuits. Therefore, make sure there are no short circuits before your attempt to repair the fuse.

The Transformer is the main power component that steps the high 220/110 wall socket voltage down to a lower level.

The High Voltage Diode and Capacitor are responsible for rectifying the AC current to DC.

All these components work to provide power to the magnetron assembly. If any of these is damaged, the magnetron will not function properly.

How to Check

This does require professional skills. You should be warned that tampering with high voltage components is dangerous even when the microwave oven is turned off.

Unplug your microwave from the electricity to ensure that it is safe to touch

Remove or unplug the high voltage capacitor, if you don’t know how to identify the parts of the microwave, use the devices handbook or check if there are prints or writings on the microwave, this will go a long way.

You will need to use a multi-meter to check the continuity of power that is passing through. You can do the multi-meter continuity test for each of the power components mentioned above.

4. The Magnetron is Faulty

Repariting Microwave Oven
A technician testing the magnetron assembly. Source: IndiaMART

Most times, when microwave ovens refuse to heat up as they should, it’s likely that the microwave oven Magnetron has become defective.

This main part of the microwave oven is responsible for generating the microwaves themselves.

When the magnetron of a microwave oven is damaged, it causes a ripple effect which might end up damaging a couple of other parts of the microwave oven too such as the fuse and the high voltage components.

How to Check

Unplug the microwave oven from the socket to ensure safety.

Take out the microwave detachable parts like the oven case.

Before you check out the magnetron, ensure you are well versed with using a multimeter and handling high voltage components.

Finally, using the multimeter, plug its leads to the magnetron and check for 2-3 ohms of resistance using the continuity test.

Calling an Electrician

If you are not a big fan of tampering with electrical appliances or you are not very familiar with a multimeter, you might want to call your electrician immediately, this will likely save time and stress because an electrician will know where to look and microwave ovens are relatively easy to fix.

Fixing the Problem

Even if you have figured out the exact issue with your microwave oven, you will still need to contact your electrician or electrical repair shop to replace the damaged or worn-out parts.

Be sure to do this as soon as possible so that other parts don’t get damaged by the microwave oven fault.


In this article, we looked at a common query: why is my microwave oven not heating up and explored the possible causes of such a dreadful issue.

We particularly looked at a common few, there could be other possible reasons why your microwave oven is not heating up. So be sure to check off all the options before calling an electrician.

Finally, remember to observe proper hygiene and cleanliness because letting food get stuck on the parts of the ovens very often might damage the oven pipes and in turn damage the microwave oven.

The same is true if your microwave oven is infested with cockroaches or insects. They can damage the sensitive components.

Also, remember to wear proper electricity-safe gloves when checking for likely faults. This is to ensure that you are constantly safe when you are working directly with electricity.


1. Why does my microwave turn on but not heat?

When your microwave switches on but does not heat up, it may be a faulty door switch. When the door switch is closed, it instructs the other microwave components to supply power and to turn off the heating. When the door switch is opened, it instructs the other microwave components to supply power and turn off the heating. Additionally, the door switch is referred to as an interlock switch.

2. How much does it cost to replace a microwave magnetron?

A microwave magnetron replacement costs between $100 and $200. This includes a part cost of $50 to $100 and labor cost of $50 to $100. A magnetron is the primary component of an appliance that generates heat.

3. Are microwaves worth repairing?

According to some experts, it is not worth repairing a malfunctioning countertop microwave because the average cost of repairs is around $70–$100, not including parts—roughly half the price of a new one of comparable quality.

4. How long does a microwave magnetron last?

A typical microwave magnetron tube has an average operating life of 2,000 hours. This means that a typical microwave oven should be able to cook and heat food for 2,000 hours before losing power. This may not seem like a significant amount of time until you consider how frequently you use your microwave oven.

5. Can you reset a microwave?

Yes, you can reset a microwave. If the controls continue to be inoperative, reset the microwave by unplugging it for 2-3 minutes. Reconnect the microwave and attempt to use it. If the controls continue to be inoperative, the microwave will require repair.
You can watch also the video below for other option on how to reset the microwave.

About the author

Gisele Perez

When not giving in-home, hands-on cooking classes, or developing recipes, Gisele "cooks" wonderful posts for us. She writes about various topics related to cooking appliances and cooking methods.


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