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Microwave not heating
By the Repair.com team
Let's fix this!
Your microwave not heating means either unappetizingly cold meals or at least 20 more minutes until chow time. How inconvenient of this modern convenience! Scan this chart for possible reasons and recourse for your microwave not heating.
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First, use this water method to double-check if there is actually an issue with your microwave not heating:
- Fill a glass measuring cup with water to the 1-cup mark.
- Set the microwave to heat on full power for 1 minute.
- Repeat the process with fresh water a handful of times.
- If the water is not consistently warm, your problem is confirmed.
WARNING: Microwave ovens (even unplugged) are extremely dangerous to work on because of their complex high-voltage circuitry. Repairing a malfunctioning microwave is not a recommended DIY project. Schedule microwave repair service with a qualified professional to test and repair.
|
Problems |
Possible causes |
What to do |
|---|---|---|
Microwave sounds normal and appears to be working but is not heating |
|
1. You may be on a previously programmed setting. Press the STOP/CANCEL button and start the heating process again, but this time on a higher power setting. 2. There may be an issue with the circuit board and its connections. Arrange for the help of a microwave repair expert. 3. Some microwave models use a relay in the high-voltage circuitry. Leave this repair to a service pro. |
Microwave is on but not starting the heating process |
Defective or loose door-safety interlock switch |
If the latch is broken, the microwave senses an open door and will not run. Schedule microwave repair service to secure or replace the interlock switch. |
Microwave is buzzing or humming loudly
|
|
Have a repair expert test and replace the magnetron, diode or high-voltage capacitor. Note: Consider purchasing a new microwave if the magnetron is the issue. The cost of one is nearly the price of a microwave. |
Microwave fails to heat intermittently |
|
1.Schedule microwave repair service to replace the safety switch on the door. 2. Microwaves installed above the range may be affected by steam from cooking. Condensation collecting on the circuitry can interrupt heating. Allow the circuitry to dry. 3. Have an microwave service professional check the wiring and fix it if loose. |
Microwave suddenly shut off while heating |
Blown internal thermal fuse |
Fuses may blow if there is an electrical overload or if mechanical safeties trip. Old age of the microwave is another reason. |
Repair or replace?
Microwave problems can be especially frustrating because these appliances aren’t easy to tinker with and fix. In fact, a deadly mistake is a real possibility when working on a microwave, making professional repair service highly recommended.
You’ll need to factor quality service into the cost of getting your microwave up and running again.
The good news is that some fixes can be made without breaking the bank. Other problems may make getting a new microwave more practical, especially when you consider that quality countertop models can be found for as low as $150. Of course, if your microwave is an expensive, built-in model, you'll have more incentive to pursue repair.
Keep in mind, also, that microwaves have an average life span of 8 years. If yours is older, your money might be better spent on a replacement.
You may want to consider replacing your microwave if the problem is the:
- Magnetron
- Circuit board
- High-voltage capacitor
- Keypad
Repair may be an option if the problem is the:
- High-voltage relay
- Interlock switch
- Diode
- Wiring
- Fuse
No matter the issue, remember to play it safe and schedule microwave repair service with a qualified professional.
Video: Troubleshooting a microwave not heating
Service pro’s plea: If in doubt, stay out. Don’t risk causing more damage to your product (or yourself!) by attempting to fix it on your own. It’s also easier and quicker for a service technician to diagnose and fix a problem when the product is assembled. In the end, you’ll save time and money.
✓ Reviewed and approved by Repair.com expert Ralph Feldkamp, Ralph's Appliance Service.
The Repair.com team
The Repair.com team is made up of experienced writers, editors and repair experts dedicated to providing you with the most reliable and comprehensive information about keeping your home running right.