Microwave Not Heating Food Properly: Possible Reasons And Solutions

Microwave Not Heating

A microwave oven is a robust home appliance. It can cook, heat, and defrost. Unfortunately, it may get choppy and break down like any other technical device. That said, one of the most common failures is when a microwave seems to be working, but the heating is significantly reduced.

We will tell you about possible reasons and ways to solve the problem. At the end of the article, I will also share with you a selection of high-quality microwave ovens.

Owner Mistakes

As a rule, they result from the lack of attention or proper maintenance of the appliance. For example:

  • Wrong mode selection. When you use Heating mode instead of Defrosting.
  • Dirty Mica cover. It protects the magnetron from contamination and fat, and equally distributes microwaves in the working chamber. If the cover is sooted, it becomes more difficult for the waves to go through it.

It is recommended to clean the mica cover once a month. Add 1 tablespoon of vinegar and 1 teaspoon of dish wash detergent to 6.5 fl oz of hot water. Dip the plate in the solution for 5 minutes, then rinse with tap water. Install it back into its place after drying.

But it’s easier to order a new one or to use a protective plastic cover.

Technical issues

Most of the causes can be detected and corrected at service centers. Why Heating Can Be Reduced?

Poor Door Fitment

The opening/closing mechanism gets worn out over time, so the door settles down and starts to come off the body unnoticed. It results in tiny gaps that allow the room air to flow into the working chamber.

It is easy to check the door fitment. Just try to slip in a sheet of paper through a closed door, and everything will be clear. There is little chance to repair the mechanism by yourself, so it is better to get it replaced with a new one at a service center.

Magnetron Reduced Performance

This is the main unit assembled with a vacuum tube. The device has a cathode and an anode. When in operation, it produces a flow of electrons (thermionic emission) sufficient to generate microwaves (power factor).

The anode gets worn out over time in operation, resulting in a reduced number of charged particles reaching the cathode. The reduced flow rate results in lower microwave power. That is the case when a microwave oven works but doesn’t heat properly.

The magnetron cannot be repaired and is subject to replacement.

Low Supply Voltage

This is typical of evening time. When we come back home from work we switch on home appliances, start cooking etc.

The normal operation voltage of a microwave magnetron is about 4kV. The voltage in a domestic power grid is 125V. That is why a microwave oven circuit has some elements converting the initial household grid voltage to the required level.

It is better if a magnetron gets an increased voltage than values below 125V. You can measure the voltage by yourself with a multimeter (tester). If power surges are common in your line, I recommend buying a stabilizer.

Inaccurate Timer Operation

As a rule, going fast is typical of a mechanical timer. It turns off the heating mode too early. However, the digital versions may also work incorrectly due to a faulty control unit.

In case of a mechanical timer, you just need to get used to the way it works. The electronic unit can be replaced.

Poor Contact of Electric Elements

A microwave oven is a technically complicated device. The circuit contains various relays, microswitches, arresters, capacitors et c. Burnt contacts significantly reduce the effective contact area. As a result, it reduces the current flow, and in the worst case it may lead to a so-called intermittent fault. In this case, a unit or a board tends to work from time to time.

Inverter Malfunctioning

The models with an inverter magnetron have a power control feature. It obviously helps to save energy. When an inverter spontaneously switches to a very low power mode, it results in reduced heating.

Bottom Line

You don’t need to take your microwave to a specialist immediately in case of a microwave malfunction. Pay closer attention to the selected modes and options, and keep your working chamber clean. If you are not skilled enough to repair home appliances by yourself, I recommend you go to a dedicated service center or ask a specialist for a visit to carry out the diagnosis.

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