Hitachi RAM-68NP3B, Service Manual, Page: 67 / 79

Checking Electrical Parts of Outdoor Unit
Turn ON circuit breaker.
Measured voltage between L N terminal
is AC220~240V?
LD353 always lit?
Check power cable.
Normal
breaker operated
Breaker is Normal
Turn OFF breaker and re-fitting power
cable connection.
Please check electric leakage. Then switch
ON the breaker again to proceed inspection.
Is the 25A fuse normal?
Abnormal
Please replace both Main PWB and
Inverter PWB.
Is the main power supply circuit normal?
Please refer to “Main Power Supply
Circuit” page for detail.
Does LD353 blink?
Abnormal
Is the F3 (2A fuse) blow?
No
No (OFF)
Reversing valve
is normal.
Please replace Main PWB.
(Main power supply circuit is abnormal)
Abnormal
Yes
Please replace Main PWB and reversing
valve coil.
(Valve or valve driver circuit is abnormal)
LD353 not blink.
Main power supply circuit is normal.
Is the breaker operated normally?
Abnormal
Please check indoor electrical.
(Consider as communication error)
Yes
Yes
Yes
Unit is entering “Hibernation Mode”
during stanby?
(All LED is OFF)
Normal
Yes
Yes
No
Yes
No
No
Just in case, turn ON the power
supply again.
Please be cautioned. When 25A fuse
blown, other parts compounded
might become broken also.
(Especially varistor, diode bridge,
IPM, smoothing capacitor and etc.)
Please check reversing valve.
Please replace both Main PWB and
Inverter PWB.
(Micon or LED is abnormal)
Please replace Main PWB.
(Main power supply circuit is abnormal)
Please replace both Main PWB and
Inverter PWB.