Low Pressure / Voltage Detected / Inverter PCB Fault

What does E49 mean?

This fault indicates a low pressure condition, low voltage detected within the system, or an inverter PCB fault. The manual lists these three distinct sub-causes for E49, any of which can lead to system malfunction.

• Low pressure in the refrigerant circuit, indicating potential refrigerant shortage or blockages.
• Voltage drop across the inverter PCB, suggesting a power supply issue or component failure.
• Malfunction of the inverter's internal voltage sensing circuit.

Click steps to track your progress.

1. 1

   Measure the system's low-side refrigerant pressure using a manifold gauge set, checking for low charge.

2. 2

   Measure the input AC voltage to the outdoor unit and check for low voltage conditions at the main terminals.

3. 3

   Inspect the inverter PCB for visible signs of damage, burnt components, or loose connections.