Mark HCNI 533, Technical Manual

Page: 74 / 84

74
8.6.3 IPM Continuity Check
Warning: Electricity remains in capacitors even when the power supply is off. Ensure
the capacitors are fully discharged before troubleshooting.
1. Turn off outdoor unit and disconnect power supply.
2. Discharge electrolytic capacitors and ensure all energy-storage unit has been discharged.
3. Disassemble outdoor PCB or disassemble IPM board.
4. Measure the resistance value between P and U (V, W, N); U (V, W) and N.
Digital Tester
Normal
Resistance value
Digital Tester
Normal
Resistance value
(+) Red (-) Black
∞
(Several M
Ω
)
(+) Red (-) Black
∞
(Several M
Ω
)
P
N U
N
U W
W V
V -