LG Microwave Combi Oven: not heating

Professional Repair Guide

What is this symptom?

If your LG Microwave Combi Oven powers on but does not heat food, you're likely facing a common issue. This symptom can occur when the microwave turns but lacks any warming effect during operation, leaving your meals cold. Understanding the potential causes, like magnetron failure, is essential for troubleshooting and repair.

Urgency: Medium

Important Tips for LG Models

  • Official support notes general causes of microwave not heating and refers users to correct settings and service options.

Possible Causes

Magnetron failure

How to Identify: Microwave runs and may sound normal but food remains cold; no heat generated even though unit turns on.

Part: Magnetron

DIY Solutions

Check settings and container

Easy 5–10 minutes
  1. Ensure cooking mode is set to appropriate heating power.
  2. Use microwave-safe containers (no metal or reflective trim).
  3. Test with a 200 ml cup of water and 1–2 minutes heating to check performance.
⚠️ Safety First: Do not use metal containers; can cause sparks and damage.

Power reset

Easy 10 minutes
  1. Unplug the microwave from the power outlet.
  2. Wait 10 minutes to allow internal systems to reset.
  3. Plug back in and test heating with water.
⚠️ Safety First: Ensure the microwave is unplugged before touching plug or outlet.

Next step

Choose the next step for not heating

Confirm the diagnosis before ordering. An error code can identify the system involved, but it does not prove that a specific part has failed.

Check during diagnosis

Most relevant component to inspect

Microwave Magnetron

Generates microwave energy for heating food and requires high-voltage service procedures.

Typical part-only price
$80 - $220
DIY difficulty
Hard
Estimated time
60-120 mins
Where can I find the model number?

Check the rating label around the door, lid, frame, rear panel, or inside the appliance cabinet. Use the complete model number, including suffixes.

Find a part that fits my model

Verify the complete model and part number on the retailer's compatibility page before ordering.

Other parts options

Check related components first; use model search as a fallback.

Model number required

Model-compatible Microwave Combi Oven parts

Enter the complete model number to browse compatible replacement parts. This is a model-based parts search, not a diagnosis that a specific component failed.

Find a part that fits my model

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Professional Repairs

Replace magnetron

Estimated Cost: $80 - $200 for part, plus labor

Replace high-voltage diode or thermal fuse

Estimated Cost: $20 - $80 parts, plus labor

Replace door switches

Estimated Cost: $15 - $50 parts, plus labor

When to Call a Professional

Water test shows little or no heating after basic checks
Signs of electrical component failure such as sparks, burning smell, or noise
Door switch or high-voltage component malfunction suspected

Preventive Maintenance

  • Use microwave-safe containers: Avoids heating inefficiency and interior damage
    Frequency: every use
  • Clean interior regularly: Improved microwave efficiency and avoids uneven heating due to soiling
    Frequency: monthly

Frequently Asked Questions

Why is my LG Microwave Combi Oven not heating?
Common causes include magnetron failure, faulty high-voltage diode, or malfunctioning door switches.
How do I fix LG Microwave Combi Oven not heating myself?
Check settings, use microwave-safe containers, and perform a power reset to troubleshoot the issue.
How much does it cost to fix not heating?
Replacing the magnetron can cost $80 - $200, while other parts range from $15 to $80, plus labor.
When should I call a technician for not heating?
If simple DIY solutions don't resolve the issue, or if you're uncomfortable with repairs, consider professional help.

References & Sources

Community Analytical Insights

Guidance from available sources; statistical claims are shown only for samples of at least 10 discussions

Common Issues Reported by Users

  • Faulty magnetron
  • Defective high voltage capacitor
  • Broken door switch or latch

User Suggested Solutions

  1. Test and replace the magnetron if necessary. Disconnect the microwave from power, remove the outer casing, locate the magnetron, and test it with a multimeter for continuity. If defective, replace it with a new one.

  2. Inspect and replace the high voltage capacitor. Ensure the microwave is unplugged, discharge the capacitor safely, and test it for functionality. Replace if faulty.

  3. Check the door switch and latch. Open the microwave door and press the switch manually to see if it engages. If not, replace the switch or repair the latch mechanism.

Limited-source guidance; percentages and success-rate claims are not shown
View Sources

Data compiled from real discussions on r/appliancerepair and r/Appliances:

  1. LG never again

Community Discussions

Microwave stopped working, seemed like the magnetron.

DIY replaced the magnetron.

DIY View on Reddit →

Source: Reddit r/appliancerepair

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