Indoor unit shows E6, compressor does not start or stops quickly; may be accompanied by humming or clicking from outdoor unit.

Safety first: High voltage and stored energy in inverter circuits can be lethal. Only open the outdoor control compartment with power isolated and capacitors discharged.

Steps:

• Visual inspection: Remove the outdoor service panel and inspect the compressor terminal cover. Ensure terminals are tight and not burnt.
• Check wiring: Confirm that the compressor leads are correctly connected to the inverter output terminals as per Blaupunkt wiring diagram.
• Measure compressor windings: With power off, disconnect compressor leads and measure resistance between all three terminals (for 3-phase inverter compressors). Values should be similar; large imbalances or open circuits indicate a bad compressor.
• Inspect inverter PCB: Look for burnt components, cracked solder joints, or bulged capacitors on the outdoor PCB. If visible damage is present, replace the entire Blaupunkt outdoor inverter PCB.
• Three-phase supply (if applicable): For commercial Blaupunkt units on 3-phase, verify correct phase sequence and that no phase is missing.

Recommendation: E6 faults usually require professional diagnosis with specialized tools.