Hitachi RAC-70YH7 Service Manual page 72

CHECKING THE INDOOR/OUTDOOR UNIT ELECTRICAL PARTS AND REFRIGERATING CYCLE
Does the timer lamp on the indoor unit blink?
Does the operation lamp on the indoor unit
start to light or blink?
Is the compressor in the outdoor unit operating?
Yes
Remove the outdoor unit cover and
electrical parts cover, and check
self-diagnosis lamp LD301
Does LD301 blink one time ?
* Repeats 0.25-second on and
2-second off.
Blinking other than
one time
See Out door unit self-diagnosis lamp
lighting mode .
Check the refrigerating cycle.
No
Yes
No
One-time blinking
Press the service switch for 1 sec.
Does the compressor operate?
(After checking, be sure to press
the service switch to stop the
operation).
Check the outdoor electrical parts.
Timer
lamp
See Troubleshooting when the timer lamp
blinks .
Remove the terminal cover and check the voltage
between terminal (C) and terminal (D)
Terminal C
(+35V)
No
Terminal A
Terminal B
Is approx. DC 33 to 37V being generated? Is the
polarity correct?
Check to see whether the F-
cable is connected incorrectly
or disconnected
Yes
No
– 82 –
No
Normal
Check the indoor electrical parts.
Terminal D
(0V)
Yes