Hitachi RAS-18YH4 Service Manual page 74

OUTDOOR UNIT
Remove the compressor connector.
IPM
INTELLIGENT
POWER MODULE
SELF DIAGNOSIS LAMPS
If your first attempt
fails, wait 3 minutes
(for the unit to re-
start) and check the
self-diagnosis lamp
status again.
LD301
LD302
LD303
With the unit set in the operating
state, press the start/stop
button.
Does the unit operate for
approximately 2 seconds (the
LD303 coming on) and then
stop due to a failure of switching
(the lamp blinking 4 times)?
Check outdoor electrical parts.
– 77 –
SERVICE SWITCH
Yes
No
• Check the drive
circuit (IMP) using
the PRD checker.
• Check the position
sensor circuit.
Normal
Check the refrigerating
cycle.