Hitachi RAM-68NP3B, Service Manual, Page: 69 / 79

LD351 10 times blink
Power supply error
LD351 5 times blink
Overload lower limit cut
Measured voltage between terminal L N
is AC220~240V?
Below AC200V or more than AC270V.
Please check power supply.
Normal
Abnormal Abnormal
Secure the reactor wire connection
or please replace the reactor.
Please replace both main PWB and
Inverter PWB. (Rectify circuit abnormal)
Secure connection of connectors
CN23 and CN25.
AC200~270V
Please replace Inverter PWB.
(Voltage detection circuit abnormal)
Normal
Normal
Abnormal
Please remove the blocking object.
Yes
Yes
Is refrigerant cycle abnormal?
Please repair the abnormal portion.
No
No
Operation stop due to
compressor is heavy
loaded.
Is DC voltage DC260V~360V
on board?
Please refer label on top of the
electrical cover on how to check
the DC voltage.
Are CN23,CN25
connectors connected
properly?
Yes
Yes
Yes
No
No
No
Yes
No
Cooling : Outdoor condenser covered with dust or something block it.
Heating : Indoor unit evap or filter covered with dust?
LD352 3 times blink
LD351 Lit
Outdoor thermistor abnormal
LD352 4~9 times blink
LD351 Lit
Exp valve thermistor abnormal
Please replace outdoor thermistor.
Please replace Main PWB.
Secure the connection of outdoor
thermistor connector.
Is the outdoor thermistor connector connected properly?
Normal
Please check outdoor thermistor wire worn out or short circuit
Please replace Inverter PWB.
Please replace exp. valve thermistor.
Normal
Abnormal
Abnormal
Normal
Secure the connection of valve
thermistor connector.
Please replace Main PWB.
Are the exp. valve thermistor connectors (CN11,CN12) connected properly?
Check all thermistor wires are worn out or short circuit?
Abnormal
Abnormal
Normal
Check reactor wire.