General Assist Technical Reference
Transformer (Power Supply) Testing
anywAiR ducted controller
Voltage outputs, resistance checks, control-box diode testing and normal LED indications
The anywAiR ducted controller uses a dual-output power supply to provide 24 V AC and 12 V DC to the control system. This procedure provides the expected readings required to assess the power supply and the control-box power input circuit.
Electrical safety: Testing includes a 240 V AC supply. Live-voltage testing must only be performed by appropriately licensed and competent personnel. Isolate and prove the supply is de-energised before disconnecting plugs or performing resistance and diode tests.
1. Power supply specifications
| Function | Connection | Expected output |
|---|---|---|
| Mains input | AC input pins 1 and 2 | 240 V AC |
| Low-voltage output | Blue and white conductors | 24 V AC |
| DC output | Red positive and black negative | 12 V DC |
Connector identification: Confirm conductor colours and plug orientation before taking measurements. Do not rely on physical pin position alone where a harness has been repaired or altered.
2. Power supply resistance test
Disconnect the power supply from mains power and from the control box. Set the multimeter to resistance (Ω), then compare the readings with the values below.
| Black meter lead | Red meter lead | Expected resistance |
|---|---|---|
| Blue | White | Approximately 1.5 Ω |
| Red | Black | Approximately 3.8 kΩ |
| AC input pin 1 | AC input pin 2 | Approximately 60 Ω |
An open-circuit reading, a near-zero reading where resistance is expected, or a reading substantially different from the reference value may indicate a damaged winding, harness or internal component. Confirm meter-lead resistance and test directly at the power-supply connector before condemning the assembly.
3. Control-box power input plug diode test
Keep mains power isolated and disconnect the power-supply plug from the control box. Set the multimeter to diode-test mode and test the control-box terminal using the polarity shown below.
| Black meter lead | Red meter lead | Expected display |
|---|---|---|
| Black | Red | 1.0 V to 1.13 V |
| Red | Black | 0.5 V to 0.7 V |
| Blue | White | O/L |
| White | Blue | O/L |
Control-box plug colour layout: black and red form the DC circuit; white and blue form the AC circuit. A result that does not correspond with the reference readings requires further investigation of the control-box input circuit before reconnecting the power supply.
4. Control PCB LED verification
After the electrical checks are complete, reconnect all plugs, restore power and observe the control PCB LEDs.
| LED | Normal indication | Interpretation |
|---|---|---|
| SYS_OK | On for 2 seconds, off for 0.5 seconds | Normal system heartbeat |
| BUSY | Solid green | Control system active |
| C9 | Dim flash | Normal display condition |
5. Diagnostic sequence
- Confirm the incoming supply: verify 240 V AC is available at input pins 1 and 2.
- Confirm both outputs: verify 24 V AC across blue and white, and 12 V DC across red positive and black negative.
- Isolate power: disconnect the assembly before resistance or diode testing.
- Test the power supply: compare winding resistance with the reference values.
- Test the control-box input: compare diode-mode readings with the specified values.
- Reconnect and verify: inspect connector seating and confirm the normal SYS_OK, BUSY and C9 LED patterns.
| Symptom | Checks | Likely area |
|---|---|---|
| Controller has no power | 240 V input, 24 V AC output and 12 V DC output | Supply, transformer or harness |
| Intermittent restart or unstable operation | Output stability, plug fit and conductor condition | Power supply, connector or control-box input |
| Supply protection operates | Resistance and diode readings with components disconnected | Short circuit in supply, harness or control box |
| No LED activity with correct outputs | Power-input plug orientation, seating and diode readings | Control-box input or PCB |
6. Important notes
- Resistance and diode tests must be completed with mains power isolated and the relevant plug disconnected.
- Observe polarity when testing or reconnecting the 12 V DC red and black conductors.
- Inspect plugs for heat damage, loose terminals, corrosion and backed-out pins.
- Do not reconnect a suspect power supply to a control box until both assemblies have been assessed.
- After replacing a power supply or control box, confirm normal tablet operation, zone control and temperature display.
- Use the correct approved replacement assembly for the controller model.