This is normal. The door may be opened at any time to add or remove food, and/or to start another cooking cycle. The cooling fan allows for proper cooling of the microwave oven. The microwave cooling fan may continue to run for several minutes after the cooking cycle has been completed.
If your microwave still operates even when the door is open, this is a good sign that the door interlock switch is faulty. The switch is meant to send a signal to the control board to turn the microwave off when the door opens, so when it becomes faulty, it won't be able to do this.
If the microwave is running, it is very dangerous as it will emit microwaves into the air. That's is a health hazard. The fan can run with the door open as it is a vent fan on a separate switch and is part of normal operation.
DO NOT USE IT. You risk going blind. crasic's point is that the magnetron, the thing that generates the microwave radiation won't work at nearly 100% efficiency while the door is open. But even 5% of a microwave can permanently damage your eye.
A faulty door seal on a microwave can cause some radiation to leak. Don't worry, these leaks will not cause you to become radioactive. However, microwave leaks can create extreme heat, and it's not something you want to take lightly.
The microwave syndrome
Researchers who have conducted scientific studies of occupational exposure to microwaves described symptoms such as fatigue, dizziness, headaches, difficulty sleeping, concentration and memory problems. These symptoms were associated with exposure to radio waves or microwaves.
Fan running during cook function
This is normal. The vent fan will automatically turn on during any cook function (on some models), acting as a cooling fan to protect the microwave.
Most over-the-range microwaves have a vent fan thermostat that will turn the vent fan on to keep the microwave from overheating. It is normal for the vent fan to come on by itself when cooking on the stovetop under the microwave. The fan will shut off after the microwave cools back down.
Leave the Microwave Door Open After Use
Remember to get back to it, as most microwaves have a built-in light that stays on for the duration that the microwave door is open. Leaving the door open will waste electricity and run down the light bulb.
4. Don't slam the door! Your microwave door has three (or sometimes four) safety interlock switches that disable the oven when the door is open. For the microwave to work properly, the switches have to line up with their corresponding latches when the door is closed.
If you leave your microwave door open, nothing will happen, except that the lightbulb will turn on if your appliance is still plugged in. There is no fear of leftover radioactivity. Microwave energy is only produced when the oven is operating. As soon as the appliance stops, it ceases to emit microwaves.
The most common cause of a constantly running microwave oven is a control board issue. The control panel relays messages from the touchpad to the internal fuse. You'll notice this issue if you also have a defective touch-pad or control panel that won't respond.
Microwave door switches are normally mounted to a bracket near the door latch. Also, microwaves usually have three or four door switches. There is a latch (sometimes referred to as a hook) attached to the inside of your microwave door that comes in contact with and activates the door switch when the door is closed.
Press the cancel/reset button to do a soft reset on your microwave. If necessary, perform a hard reset by unplugging your microwave for 30 minutes, then plug it back in.
The cooling fan should only run for an hour after you've finished cooking. If the cooling fan on your appliance has continued to run for more than an hour it could indicate an issue.
Ducted or vented microwaves feature exhaust fans that vent air outside of the house. Recirculating, non-ducted or updraft microwaves filter air then push it back into the kitchen. Convertible microwaves give you the option to select your ventilation type.
The fan you can hear is actually a cooling fan which is located behind the control panel. This will continue to run for a while after the oven has been turned off to assist the cooling process. The fan will stop automatically when the oven has cooled down sufficiently.
To turn off oven fans:
Turn off the convection fan. On electric ovens, select Bake Mode to take the oven out of Convection Mode. On Gas Ranges, turn the convection fan off using the Fan switch above the oven door.
The oven control board sends voltages to the heating elements—bake and broil—depending on the user input and sensor settings. If one of the control board's relays ends up shorting, the board may send continuous voltage, which means the oven may continue to heat even after it is turned off at the controls.
Microwave radiation leaks are hard to detect because you can't smell or see microwaves. The U.S. Food and Drug Administration (FDA), which regulates radiation-emitting products such as microwave ovens, advises against standing directly in front of or up against the oven while it is operating.
With normal usage for an average family and good maintenance, a microwave often lasts for 7 to 8 years. If the microwave is used less frequently by a single person or a couple and is well-maintained, the lifespan can increase to up to 10 years.
from getting in. Because of this shielding effect, your hand inside a non-running microwave actually receives less radiation than your hand out in the open air. Either way, the radiation you are exposed to is so low-energy that there is nothing to be concerned about.
The FDA rules also say that only a certain amount of radiation can leak from the microwave at about 2 inches away or farther. The amount is 5 milliwatts per square centimeter, which is a level of radiation that is not dangerous to people.