Common symptoms
- The equipment shows H5 or a power protection related alarm.
- The compressor attempts to start and then stops.
- The inverter board enters protection after power-up.
Pilot technical case
H5 error, IPM and compressor not starting
An H5 Error usually requires an ordered review of the power circuit, DC bus, IPM module, capacitors and compressor condition. This workflow does not issue a definitive diagnosis.
Possible cause and recommended checks. Requires technical validation. Escalate to human support if measurements are unclear.
Possible causes
- IPM module in protection or with internal damage.
- DC bus out of range or with abnormal ripple.
- Degraded capacitors or reduced capacitance.
- Compressor winding, insulation or current outside expected parameter.
Recommended checks
- Confirm model, board code and power supply conditions.
- Review connectors, terminals, solder joints and visible damage signs.
- Record measurements before replacing components.
DC bus check
- Verify DC voltage with a suitable instrument and safe procedure.
- Compare the reading against the equipment documentation.
- Escalate if the bus fluctuates, drops under load or does not match the technical reference.
IPM measurement
- Check shorts across power terminals according to the manufacturer technical guide.
- Compare readings across phases to detect relevant differences.
- Do not confirm IPM failure before ruling out supply, compressor and peripherals.
Compressor test
- Validate continuity and balance between windings.
- Check insulation with suitable equipment.
- Confirm measurements are consistent before energizing again.
Technical validation
Escalate this case with the support team
Attach measurements, board photos, model code and symptoms to guide the review.