Unit displays P0 and may limit compressor speed or shut down.

Safety first: High DC bus voltages (up to ~400VDC) are present. Only perform external checks unless qualified.

Steps:

• Check mains voltage: Have a qualified person measure supply voltage at the outdoor unit. Correct any supply issues (loose connections, undersized wiring).
• Inspect terminals: With power off, tighten all power terminal screws and check for heat damage.
• Environmental factors: Avoid sharing the circuit with large inductive loads (welders, large motors) that cause voltage spikes.
• PCB issues: Persistent P0 with correct supply suggests a failing PFC or DC bus on the Blaupunkt outdoor inverter PCB, which should be replaced.