Microwave runs but does not heat; no error code displayed
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.
Possible Causes
How to Fix / Troubleshooting
Critical Safety Warning: The high-voltage section of a microwave is lethal. If the unit runs (light, fan, turntable) but does not heat, internal high-voltage components are likely at fault. Do not open the cabinet unless you are trained.
User-level checks:
- Confirm the unit is not in demo mode (check manual).
- Test with a microwave-safe cup of water for 1–2 minutes. If the water stays cold, heating is not occurring.
- Stop using the microwave and unplug it.
Technician-level steps:
- Discharge the high-voltage capacitor safely.
- Test the magnetron, HV diode, capacitor, and transformer for proper operation.
- Replace any failed component with Summit-compatible parts.
Due to the danger, most homeowners should have a professional perform this repair or replace the microwave.