Outdoor Unit LED 1 Flash — Serial forward transfer error

What does 1 Flash (Outdoor Unit) mean?

The LED on the outdoor unit flashes once, indicating a problem with the serial forward communication. This means data is not being sent correctly from one part of the system to another.

• Incorrect wiring or loose connections.
• External interference from electromagnetic waves.
• A fault with the interface PCB in the outdoor unit.

Click steps to track your progress.

1. 1

   Stop the heat pump system by disconnecting power, wait at least one minute, then restart the system.

2. 2

   Check all electrical connections between the hydraulic unit and the outdoor unit, ensuring they are secure and correctly wired.

3. 3

   Inspect the area for any equipment generating strong electromagnetic waves that might be interfering with the system's communication.

4. 4

   Verify the power supply voltage to the outdoor unit is between AC 198-264 V at terminals N and L. Consult a qualified technician for voltage checks.

5. 5

   Check the serial signal voltage between terminals 2 and 3 of the outdoor terminal block; it should fluctuate between AC 70 V and AC 130 V. If not, the Interface PCB may need replacement by a professional.