This guide provides diagnostic steps for verifying correct operation of the Electronic Expansion Valve (EEV) used in Fujitsu VRF J-Series systems.
Applicable parts: UTR-EV2A, UTR-EV3 (Option Kits).
1. Check Circuit Connection
Confirm proper connection at connector CN14 on the PCB.
Verify each wire corresponds to the correct pin position:
CN14 terminals: Red, Orange, White, Brown, Blue, Yellow, Common.
2. Check Solenoid Coil
Remove CN14 and measure resistance between wires to confirm coil integrity.
| Wire Pair | Expected Resistance |
|---|---|
| Red – Orange | 140 Ω |
| Red – White | 140 Ω |
| Orange – White | 300 Ω |
| Brown – Blue | 140 Ω |
| Blue – Yellow | 300 Ω |
⚠ If any resistance value is abnormal, replace the Control PCB.
3. Initialize Positioning
Power off the outdoor PCB.
Power back on to reinitialize the EEV several times.
4. Check Control PCB Voltage
With CN14 disconnected, confirm DC +12 V output from the control PCB.
If 0 V is detected, replace the main PCB.
5. Check Operation Sound
When power is turned on, listen for the magnetized clicking sound from the EEV motor.
If no sound occurs, the control PCB may be defective.
6. Verify Solenoid Valve Operation
Confirm open/close operation by measuring temperature differences:
Closed: High temperature at inlet, normal at outlet.
Open: High temperature at both inlet and outlet.
7. Check Strainer for Blockage
Inspect temperature difference across the strainer terminals:
Large temperature difference → possible clogging.
Change system mode (Heating ↔ Cooling) to verify refrigerant movement.
Summary of Key Diagnostics
| Check Point | Focus | Normal Condition |
|---|---|---|
| CN14 wiring | Electrical connection | All wires secure |
| Solenoid resistance | Coil integrity | 140 Ω / 300 Ω |
| PCB voltage | Power output | 12 V DC |
| EEV initialization | Repositioning | Audible operation |
| Thermal test | Valve response | Normal temp variation |
