Parts:
4-Way Valve: P/No. 9970035012
Solenoid Coil: P/No. 9900191016
Check Point 1: Circuit Connection
Confirm correct wiring between connector CN6 on the Control PCB and the Solenoid Coil.
Ensure there is DC12V control signal during heating operation.
Verify that all wiring (Black/White) is secure and free of corrosion or breaks.
Check Point 2: Solenoid Coil Resistance
Disconnect CN6 from the PCB and measure resistance across the coil.
Expected Resistance: approximately 1.6 kΩ
If resistance is open or out of range, replace the Solenoid Coil.
Check Point 3: 4-Way Valve Operation
Check the pipe temperatures to confirm correct valve switching between heating and cooling:
Heating Operation (Valve ON):
Coil energized
Hot gas directed to indoor heat exchanger
Cooling Operation (Valve OFF):
Coil de-energized
Hot gas directed to outdoor heat exchanger
If the valve fails to switch properly, replace the 4-way valve.
Check Point 4: Solenoid Coil Voltage
Measure voltage at CN6 on the Control PCB during heating operation.
Expected Voltage: 220V ± 20V (when compressor is running)
If voltage is not present, replace the Control PCB.
Summary Table
| Check Point | Test Item | Expected Reading | Action if Abnormal |
|---|---|---|---|
| 1 | Circuit Connection | Secure, correct polarity | Repair wiring |
| 2 | Coil Resistance | ~1.6 kΩ | Replace Solenoid Coil |
| 3 | Valve Operation | Switches with temp change | Replace 4-Way Valve |
| 4 | Coil Voltage | 220V ± 20V | Replace Control PCB |
