General Assist Technical Reference
4-Way Valve & Solenoid Coil Testing
Circuit, resistance, valve operation and coil voltage checks
Use this procedure to check the electrical connection and operation of the 4-way valve solenoid circuit, then confirm whether the fault is associated with the wiring, solenoid coil, valve body or Control PCB.
Electrical safety: Live voltage testing must only be completed by suitably qualified personnel using appropriate PPE and safe test methods. Isolate power before disconnecting CN6 or carrying out resistance checks.
Source data note: The supplied procedure references a DC12 V control signal in Check Point 1 and 220 V ± 20 V at CN6 in Check Point 4. Confirm the correct voltage for the applicable model using the relevant service data before carrying out live testing.
Parts
| Component | Part Number |
|---|---|
| 4-Way Valve | 9970035012 |
| Solenoid Coil | 9900191016 |
1. Circuit Connection
- Confirm correct wiring between connector CN6 on the Control PCB and the Solenoid Coil.
- Ensure there is a DC12 V control signal during heating operation, as specified in the supplied procedure.
- Verify the Black/White wiring is secure and free from corrosion, damaged terminals or conductor breaks.
2. Solenoid Coil Resistance
Power must be isolated before this test.
- Disconnect CN6 from the PCB.
- Measure resistance across the solenoid coil.
Expected resistance: approximately 1.6 kΩ
If the coil is open circuit or the resistance is significantly outside the expected range, replace the Solenoid Coil.
3. 4-Way Valve Operation
Check pipe temperatures to confirm that the valve changes refrigerant flow correctly between heating and cooling operation.
| Mode | Coil State | Expected Refrigerant Direction |
|---|---|---|
| Heating | Energized | Hot gas directed to the indoor heat exchanger |
| Cooling | De-energized | Hot gas directed to the outdoor heat exchanger |
If the electrical checks are correct but the valve does not switch correctly, replace the 4-Way Valve.
4. Solenoid Coil Voltage
- Measure voltage at CN6 on the Control PCB during heating operation.
- The supplied procedure specifies an expected reading of 220 V ± 20 V while the compressor is running.
Before testing: Confirm the correct CN6 voltage for the applicable model because the supplied source also references a DC12 V control signal earlier in the procedure.
If the required voltage is not present and the wiring is confirmed correct, the supplied procedure directs replacement of the Control PCB.
Summary
| Check Point | Test Item | Expected Result | Action if Abnormal |
|---|---|---|---|
| 1 | Circuit Connection | Secure wiring and correct connection | Repair wiring / terminals |
| 2 | Coil Resistance | Approx. 1.6 kΩ | Replace Solenoid Coil |
| 3 | Valve Operation | Valve switches and pipe temperatures change with mode | Replace 4-Way Valve |
| 4 | Coil Voltage | 220 V ± 20 V stated in supplied procedure | Replace Control PCB if voltage is absent after wiring is confirmed |
Reference Image
General Assist Technical Reference