24
Indoor unit operates.
Outdoor unit does
not operate.
Indoor unit does not
receive the signal from
remote controller.
OPERATION INDICATOR
lamp on the indoor unit is
blinking ON and OFF.
Outdoor unit
operates only
in Test Run
operation. *1
Indoor unit
operates, when
the emergency
operation switch
is pressed.
Indoor unit does
not operate, when
the emergency
operation switch
is pressed.
Check room
temperature
thermistor.
Refer to 9-7.
"Test point
diagram and
voltage".
Refer to 9-6.
"Check of remote
controller and
indoor electronic
control P.C. board.
1. Check indoor/out-
door connecting wire.
(Check if the power is
supplied to the indoor
unit.)
2. Refer to 9-6. "Check
of indoor P.C. board
and indoor fan motor".
Left lamp
2-time blink
Cause:
Indoor unit
• Trouble
of room
temperature
/ indoor coil
thermistor
Left lamp
Blink ON
and OFF at
0.5-second
intervals
Cause: In-
door/ Out-
door unit
• Miswiring
or trouble of
serial signal
Left lamp
3-time blink
Cause:
Indoor unit
• Trouble of
indoor fan
motor
Left lamp
4-time blink
Cause:
Indoor unit
• Trouble
of indoor
unit control
system
Start
Check room
temperature
thermistor
and indoor
coil thermis-
tor. Refer to
9-7. "Test
point diagram
and voltage".
Refer to 9-6.
"How to
check mis-
wiring and
serial signal
error (when
outdoor unit
does not
work)".
Refer to
9-6. "Check
of indoor fan
motor".
Replace the
indoor elec-
tronic control
P.C. board.
Outdoor unit
does not
operate even
in "Test run
operation". *1
Check the
outdoor unit.
*1 "Test Run operation" means the operation within 30 minutes after the emergency operation switch is pressed.
If blinking of OPERATION INDICATOR lamp cannot be checked, it can be checked with failure mode recall function.
*2 There is possibility that diesel explosion may occur due to the air mixed in the refrigerant circuit.
First, ensure that there are no leakage points on the valves, flare connections, etc. that allow the air to flow into the
refrigerant circuit, or no blockage points (e.g. clogged or closed valves) in the refrigerant circuit that cause an increase
in pressure.
If there is no abnormal point like above and the system operates cooling mode normally, the indoor thermistor might
have a problem, resulting in false detection.
Check both the indoor coil thermistor and the room temperature thermistor, and replace faulty thermistor(s), if any.
(Do not start the operation again without repair to prevent hazards.)
Left lamp
6-time blink
Cause:
Outdoor unit
• Trouble of
thermistor
in outdoor
unit
Refer to
"Check of
outdoor ther-
mistors".
Refer to outdoor unit service manual.
Left lamp
7-time blink
Cause:
Outdoor unit
• Trouble
of outdoor
control
system
Replace the
deicer P.C.
board.
Left
lamp 14-
time or more
blink
Cause:
Outdoor unit
• Other ab-
normality
Indoor/out-
door unit
• Trouble of
thermistors
• Check “Flow
chart of the
detailed
outdoor unit
failure mode
recall func-
tion.”
• Check
thermistors.
Refer to
“Test point
diagram and
voltage” in
the service
manual of
indoor and
outdoor unit.
*2
MS-CP30VA
OBH782A
