Hitachi RAS-18YH6 Service Manual page 72

OUTDOOR UNIT
Remove the compressor connector.
1/ 2/ IPM (Intelligent Power Module)
3/ Service Switch
4/ Self-Diagnosis Lamp
MAIN P.W.B.
IPM
If your first attempt
fails, wait 3 minutes
(for the unit to re-
start) and check the
self-diagnosis lamp
status again.
LD303
LD302
LD301
HIC
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.
– 70 –
SERVICE SWITCH
Yes
No
Check the drive
circuit (IPM) using
the PRD checker.
Check the position
sensor circuit.
Normal
Check the refrigerating
cycle.