H3
Haier Low voltage or power supply under-voltage protection

Microwave shows H3 and will not heat

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Line voltage too low, Overloaded household circuit, Faulty internal power supply, Loose power cord connection

How to Fix / Troubleshooting

Safety: Unplug the microwave before moving or inspecting the cord.

  • Check circuit load: Ensure the microwave is on a dedicated circuit or not sharing with high-draw appliances (heaters, refrigerators, etc.).
  • Try another outlet: Plug the microwave into a different outlet on a separate circuit and test.
  • Inspect power cord: Look for cuts, kinks, or burn marks on the cord and plug. Do not use the microwave if the cord is damaged.
  • Power reset: Unplug for 10 minutes, then test again.
  • Persistent H3: Indicates an internal power supply or control board issue. Have the main PCB inspected and replaced by a technician.
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Repair Difficulty

Medium 3/5

Required Part

Power Cord or Main Control Board
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