Unit attempts to start, then stops with E5; compressor may not run or runs briefly then shuts down.

Safety first: This fault involves high current and high voltage. Always isolate power at the main breaker and do not touch live components.

Steps:

• Check supply voltage: With a multimeter (and power restored briefly), verify that the supply voltage at the outdoor unit matches the Blaupunkt nameplate rating. Low or fluctuating voltage can trigger E5.
• Inspect power connections: Turn power off again and tighten all terminal screws at the outdoor unit’s power block. Look for signs of overheating or melted insulation.
• Check condenser coil and fan: Ensure the outdoor coil is clean and the fan spins freely. A stalled fan can cause compressor overcurrent.
• Compressor test (advanced): With power off and capacitor discharged, measure compressor winding resistances and check to ground. Very low resistance between terminals or any continuity to ground indicates a failed compressor.
• Board/IPM diagnosis: If compressor tests good but E5 persists, the inverter IPM on the outdoor PCB may be faulty. Replacement of the complete Blaupunkt outdoor inverter PCB is typically required.

Note: Due to the risk of electric shock and refrigerant system damage, E5 faults are best handled by a qualified technician.