Breville Microwave: buzzing noise, fan running after cycle

Professional Repair Guide

What is this symptom?

Is your Breville Microwave producing a buzzing noise during or after cooking, with the fan running longer than expected? This could indicate several issues, including normal cooling operations or potential blockages. Understanding the causes can help you troubleshoot effectively and restore your microwave's functionality.

Urgency: Medium

Important Tips for Breville Models

  • Breville microwaves may exhibit fan overrun controlled by internal temperature sensors; fan running after heavy cooking can be normal but extended run due to faulty thermostat/control board is reported in community guides.

Possible Causes

Normal cooling fan operation

How to Identify: Fan runs for a few minutes after heavy or long cooking as part of normal cooling process with moderate buzzing fan noise.

Part: Cooling fan

Blocked vents or poor ventilation

How to Identify: Fan runs longer than usual if vents are clogged with debris, kitchen heat or poor surrounding ventilation.

Part: Air vents/exhaust

Faulty thermostat or temperature sensor

How to Identify: Fan continues running even when unit is cool, possibly accompanied by overheating symptoms or incorrect fan shut-off.

Part: Temperature sensor/thermostat

Stuck fan relay on control board

How to Identify: Fan runs continuously regardless of temperature, unit not cooling correctly, reset does not stop fan.

Part: Control board (fan relay)

Fan motor wear or obstruction leading to buzzing

How to Identify: Buzzing louder than normal, grinding sound from fan area, possible debris or worn bearings.

Part: Cooling fan motor

DIY Solutions

Ensure proper ventilation and cool down periods

Easy 5–10 minutes
  1. Ensure microwave has adequate space around it for airflow (following Breville guidelines).
  2. Check and clear any visible dust/debris from vents or exhaust grills.
  3. Allow time between back-to-back cooking cycles to let unit cool naturally before next use.

Power reset and observation

Easy 10–15 minutes
  1. Unplug microwave from the power outlet for 10 minutes.
  2. Plug back in and observe fan behavior without running a cycle to check if fan runs continuously.
  3. Run a short heating cycle and check if fan still runs past a few minutes cooling period.

Professional Repairs

Replace faulty thermostat or temperature sensor

Estimated Cost: $50–$150

Control board repair or fan relay replacement

Estimated Cost: $100–$300

Cooling fan motor replacement

Estimated Cost: $30–$100

When to Call a Professional

Fan continues to run indefinitely even when unit has cooled and after resetting power
Fan buzzing is unusually loud or grinding, suggesting mechanical wear
Any unusual electrical smells, overheating, or signs of component failure

Preventive Maintenance

  • Clean vents and exhaust regularly: Excessive fan run time due to blocked airflow
    Frequency: monthly
  • Allow cool down gaps between long cooking cycles: Overheating that causes extended fan operation
    Frequency: as needed (when heavy use)

Frequently Asked Questions

Why is my Breville Microwave buzzing noise, fan running after cycle?
Common causes include normal cooling fan operation, blocked vents, or a faulty thermostat.
How do I fix Breville Microwave buzzing noise, fan running after cycle myself?
Check for proper ventilation, clear dust from vents, and perform a power reset.
How much does it cost to fix buzzing noise, fan running after cycle?
Professional repairs can range from $30 to $300, depending on the issue.
When should I call a technician for buzzing noise, fan running after cycle?
If DIY solutions fail or you suspect a faulty control board or fan motor.

Community Analytical Insights

Analysis based on real user discussions from appliance repair communities

Can I Fix This Myself?

55%
DIY Success Rate Difficulty: Either

Common Issues Reported by Users

  • Faulty high-voltage capacitor causing buzzing noise and continuous fan operation
  • Defective magnetron leading to abnormal sounds and fan running post-cycle
  • Worn-out cooling fan or fan motor malfunction resulting in persistent noise

User Suggested Solutions

  1. Inspect the high-voltage capacitor for any visible damage or bulging. If damaged, discharge the capacitor safely and replace it with a new one.

  2. Test the magnetron with a multimeter for continuity. If it fails the test, replace the magnetron following safety precautions.

  3. Check the cooling fan for obstructions and test the fan motor. Replace the fan motor if it is not functioning properly.

Analysis based on 1 community discussions
View Sources

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

  1. Breville Smooth Wave Microwave making buzzing noise?

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