No 10-20 V DC between S2 and S3 — Serial signal confirmation issue

What does Amplitude of 10 to 20 V DC not present between S2 and S3 mean?

The expected amplitude of 10 to 20 V DC is not detected between outdoor terminal block S2 and S3. This measurement is used to confirm the serial signal.

• Faulty serial signal transmission
• Problem with the outdoor control board
• Wiring issue affecting signal measurement

Click steps to track your progress.

1. 1

   Ensure the bridge between outdoor terminal block S2 and S3 is correctly placed (if applicable for testing).

2. 2

   Turn off the power supply before checking connections.

3. 3

   If the voltage is not present, replace the inverter P.C. board.

4. 4

   Verify connections and wiring integrity.