Hitachi RAK-15QPC Service Manual page 78

1. Failure phenomenon: The power will not become turned on.
Neither initialization, remote control, nor any other step works on the vane position at power-on.
Situation
[ Estimated failure
locations ]
Cautions
Diagnosis flow
Initiating troubleshooting
Is the power supply voltage normal?
Has the varistor VA001 not become burned?
Normal power supply voltage: AC 230 V
Is a voltage of AC 2 0 V applied between WR001-WR002 3
Yes
Replace the 3.15 A fuse, disconnect the CN2
(indoor fan motor), and conduct an operation
check. Has the product worked?
Disconnect the CN2 and check for continuity
between the "red" and "black" wires of the
indoor fan motor by using a tester. Is it short-
circuited?
Apply the black lead of the tester to the red
lead of the motor. Apply the red lead of the
tester to the black lead of the motor.
Replace the "indoor electrical parts".
Is DC 5 V applied to both ends of the C106 and C113?
Is the CN16 securely connected?
Replace the "indoor electrical parts".
・ 3.15 A fuse blown out
・ Control power circuit
・ Connector loose, wire break
・ Before work, check the power supply voltage. An abnormal voltage may be being supplied in
some rare occasions due to a defect in the indoor wiring (a wire break in the neutral wire of the
single-phase 3-wire power supply).
・ If the 3.15 A fuse has blown out, eliminate the cause of the fuse blowout. Otherwise, there will occur
another fuse blowout.
・ If the 3.15 A fuse has blown out due to an abnormally high voltage to the power supply, the varistor
(VA001) will deteriorate and become destroyed as well.
・ On a repair service visit due to the failure phenomenon of "The power will not become turned on",
take a "3 .15 A fuse" and a "varistor" with you.
Normal
No
Another fuse blowout
No
Yes
Yes
Estimated cause of fuse blowout ・ Abnormally high voltage applied to the power supply
Abnormal
Replace the "3.15 A fuse".
Replace the "varistor (VA001)".
?
Yes
Yes
No
No
78
・ Indoor fan motor out of order
・ Power circuit out of order
Get the indoor wiring back to its
normal condition, then conduct
a final check.
Replace the "indoor fan motor".
Replace the "indoor electrical
parts".
Replace the "indoor fan motor".
Replace the "indoor electrical
parts".
Reconnect the connector correctly.