Unit displays F2 and may stop heating or cooling; defrost cycles may be abnormal.

Safety first: Isolate power at the outdoor disconnect before opening the unit.

Steps:

• Locate ambient sensor: Typically mounted near the outdoor air intake grille, not directly on the coil, with a small plastic shield.
• Inspect condition: Check for cracked housing, broken wires, or corrosion at the connector.
• Test resistance: Disconnect from PCB and measure resistance at ambient temperature. Compare to Blaupunkt’s NTC specification.
• Replace sensor: Install a new Blaupunkt outdoor ambient temperature sensor if faulty. Mount it in the same location and orientation to avoid direct sunlight or rain affecting readings.