General Assist Technical Reference
3 Wire Remote Controller Signal Test
Testing Y1, Y2 and Y3 at a 3-wire wired remote controller
Use this procedure to confirm controller power and communication signal between the wired remote controller and indoor unit.
Electrical safety: These checks are performed on an energised low-voltage control circuit. Testing should only be carried out by appropriately qualified service personnel using suitable test equipment and safe work practices.
1. Terminal identification
| Terminal | Wire colour | Function |
|---|---|---|
| Y1 | Red | 12 V DC supply |
| Y2 | White | Signal |
| Y3 | Black | COM / common |
The signal test can be completed at the Y1, Y2 and Y3 terminals on the rear of the wired remote controller.
2. Check controller supply — Y1 to Y3
| 1 | Set the multimeter to measure DC voltage. |
| 2 | Measure between Y1 (Red) and Y3 (Black / COM). |
| 3 | Expected reading: approximately 12 V DC. The detailed training diagram specifies no less than 11.4 V DC. |
If the 12 V DC supply is not present: the source training material identifies the remote controller board as a possible fault point. Confirm wiring and connections before condemning the controller.
3. Check the communication signal
Test A — Y2 terminal to Y3
- Disconnect the Y2 wire from the remote controller.
- Measure between the controller's Y2 terminal and Y3.
- A fluctuating / pulsing DC signal should be present.
Test B — Indoor-unit cable to Y3
- Leave the Y2 conductor disconnected from the remote controller.
- Measure between the disconnected Y2 wire going to the indoor unit and Y3.
- A fluctuating / pulsing DC signal should be present.
Signal voltage shown in the training material: the overview slide describes a fluctuating 7–12 V DC signal, while the detailed test diagram labels the pulse as 7–11 V DC. Treat the important diagnostic characteristic as a fluctuating/pulsing signal rather than a steady voltage.
4. Interpreting the results
| Test | Expected result | If abnormal |
|---|---|---|
| Y1 to Y3 | Approx. 12 V DC; detailed diagram states not less than 11.4 V DC. | Check wiring and supply. The controller board may be faulty if the supply is absent. |
| Controller Y2 to Y3 | Fluctuating / pulsing signal, shown as 7–11 V DC on the detailed diagram. | No pulse indicates the controller side is not producing the expected communication signal. |
| Indoor-unit Y2 cable to Y3 | Fluctuating / pulsing signal, shown as 7–11 V DC on the detailed diagram. | No pulse indicates the expected communication signal is not present on the indoor-unit side. |
Quick sequence: First confirm the 12 V DC supply between Y1 and Y3. Then disconnect Y2 and compare the communication pulse on the controller Y2 terminal and the Y2 cable leading to the indoor unit.
Terminal functions and voltage ranges in this article are based on the supplied General Assist training material for the 3-wire remote controller signal test. Always refer to the applicable model service documentation where model-specific information differs.