Unit shows A2 alarm, compressor will not start, no heating or cooling

Safety warning: Refrigerant circuits must only be serviced by certified personnel. Do not open any refrigerant connections.

User checks:

• Power cycle the unit: Turn off the main isolator for 5 minutes, then turn back on and attempt to reset the alarm from the Nibe control panel.
• Check air and water flow: Ensure all air filters (for air‑to‑air/air‑to‑water models) are clean and that water circulation pumps are running. Poor heat transfer can cause abnormal pressures.
• Inspect for obvious leaks: Look around refrigerant connections and coils for oil stains, which may indicate a leak. Do not touch or tighten fittings.

Technician work required: If the A2 alarm persists, a Nibe‑qualified technician must check system pressures, test the low‑pressure switch, inspect the electronic expansion valve, and locate/repair any refrigerant leaks.