Can a Microwave Work Without a Fan? Appliance Safety Advice

Microwaves require all sorts of parts to function safely, including fans, lights, magnetrons, turn tables, and more. If any of these components fail or don’t work as they should, your microwave will be compromised. While it’s usually fine if the turn table can’t rotate fast enough or the lights are dim, the fan plays an essential role.

A microwave can’t work without a fan because the fan prevents the magnetron and turn table motor from overheating. Using a microwave without a fan can result in heightened fire risks, damaged parts, and overcooked food. It can also damage the microwave’s control board.

In this article, I’ll show you why a microwave can’t work without a fan, what ruins microwave fans, and what you can do about it. Enjoy!

What Happens if a Microwave Fan Stops Working?

If a microwave fan stops working, the capacitor and magnetron will likely get too hot for most safety standards. It could cause the breaker to trip due to overheating, but you’ll also notice that the microwave feels much hotter after you open the door.

However, you can use a microwave without a light. Microwave fans are among the most important parts of the appliance. Once the fan goes out, there’s a high chance that the magnetron goes out. Since magnetrons often cost close to the same as a microwave, you’ll likely have to get a different unit.

The primary reason microwave fans are so important is that they stop excessive heat buildup. The same issue can make a tower fan catch on fire or a broken car fan smoke through a car engine. Listen for the subtle fan’s hum when you turn on the microwave to know if it’s working.

If you have an exhaust fan attached to the top of your microwave, it’s even more important to maintain it. Once the exhaust fan goes out, you won’t be able to clear the smoke from your oven, stove, and other cooking appliance.

Microwaves mounted over stoves often have two fans: one for cooling the magnetron and another to remove smoke and heat from the cooking range. Each microwave motor has its own motor that’s wired to the neutral and hot terminals on the control board.

What Causes a Microwave Fan to Fail?

Microwave fans fail due to gradual wear and tear, incorrect replacement parts, and electric surges. Your microwave fan can also fail if the control board malfunctions because it’ll stop sending electricity to various parts of the microwave. Some built-in microwave fans stop working if they’re stored in hot, humid areas.

According to Consumer Reports, microwaves should last 10 years. I’ve had microwaves that have lasted well over a decade, while others only make it about 5 years. It all comes down to user error, microwave quality, and knowing when to repair or maintain the appliance.

Here’s what can make a microwave fan stop working:

• Rust can damage a microwave fan motor. Rust forms on turn table motors and fan motors in microwaves if they’re exposed to moisture. Unfortunately, steam is almost inevitable when using microwaves. However, you can prevent premature wear and tear by wiping the inside of the appliance regularly.
• Microwave fan motors won’t work if they don’t get power from the control board. The control board is the communication center for everything in the microwave. If the control board doesn’t get power from the circuit breaker or wall outlet, it can’t supply electricity to the fan motor. A faulty control board can also make the microwave display dim.
• Rattling and rough movements can damage a microwave fan. Be careful not to toss or drop your microwave when you’re unpackaging or moving it to a new location. Never shake a microwave because it can break the fan, turn table, magnetron, and many other parts.

Since you can’t use a microwave without a fan, it’s important to take caution when handling and moving the appliance. Much like desk fan longevity, microwave fan lifespans are quickly reduced if they’re clogged by hair, grime, and other debris.

What Should You Do if Your Microwave Fan Doesn’t Work?

If your microwave fan doesn’t work, follow these instructions closely:

1. Open the front panel of the microwave to reveal the control board. Some microwaves have control boards behind the rear panel. Remove the screws, then use a flathead to gently pry the panel and reveal the control board.
2. Use a multimeter to test the voltage at the control board, then do the same for the fan terminals. Your microwave’s control board should read 120v to 220v, depending on the connected circuit breaker. Most microwaves are 120v since they don’t need higher voltage during peak operation.
3. If the control board doesn’t have voltage, replace the breaker. This reading means the control board can’t power the digital display, fan, light, motors, or anything else in the microwave. Always use the same voltage on the new breaker to prevent power surges.
4. If the control board has voltage, but the fan doesn’t work, replace the fan. You’ll notice the breaker works fine and the control board is powering the displays, lights, and so on. Swap the fan by turning off the power, removing the fan’s wires, and connecting them to a new one in the side wall or on top of the microwave.
5. If replacing the fan doesn’t work, replace the control board. This is rare because a damaged control board will usually cause problems throughout the microwave. However, if nothing works properly, the control board is almost always the culprit.

You should also make sure that your microwave is clean if you keep having to replace parts. For example, Part Select recommends cleaning the grease filter below your microwave if it’s mounted above a stove. This will prevent grease and grime from clogging the fan and corroding the wire terminals.

Note: Microwave fans need to be able to cool the magnetron. If the fan stops working, you might notice your microwave starts whistling. This happens because the magnetron is rusting and overheating, which means it might need to be replaced alongside the fan.