Mitsubishi Electric MSZ-HM15NA Service Manual page 20

9-3. INSTRUCTION OF TROUBLESHOOTING
Start
Indoor unit operates.
Outdoor unit does not
operate.
Outdoor unit Outdoor unit
operates only does not
in Test Run operate even
operation. * in Test Run
operation. *
Check room
Refer to "How
temperature
to check
thermistor.
inverter/com-
Refer to 9-7.
pressor".
"Test point
diagram and
voltage".
Upper lamp Upper lamp
Blink ON 2-time blink
and OFF at Cause:
0.5-second Indoor unit
intervals • Trouble
Cause: of room
Indoor/Outdoor temperature
unit / indoor coil
• Miswiring or thermistor.
trouble of se-
rial signal.
Refer to Check room
9-6. "How temperature
to check mis- thermistor
wiring and and indoor
serial signal coil thermis-
error". tor. Refer
to 9-7."Test
point diagram
and voltage".
OBH746D
Indoor unit operates. Indoor unit does not
Outdoor unit does not receive the signal from
operate normally. remote controller.
Indoor unit
Unit does not
operates, when
operate nor-
the emergency
mally in COOL
operation switch
or HEAT mode
is pressed.
operation.
Refer to Refer to 9-6.
"Check of R.V. "Check of remote
coil". controller and
indoor elec-
tronic control P.C.
board".
Upper lamp
Upper lamp
3-time blink 4-time blink
Cause: Cause:
Indoor unit Indoor unit
• Trouble of • Trouble
indoor fan of indoor
motor. unit control
system.
Refer to Replace the
9-6. "Check indoor elec-
of indoor fan tronic control
motor". P.C. board.
OPERATION INDICATOR
lamp on the indoor unit is
blinking ON and OFF.
Indoor unit does
not operate, when
the emergency
operation switch
is pressed.
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".
Upper lamp Upper lamp
5-time blink 6-time blink
Cause: Cause:
Outdoor unit Outdoor unit
• Outdoor • Trouble of
power sys- thermistor in
tem abnor- outdoor unit.
mality.
Refer to Refer to
"How to "Check of
check outdoor ther-
inverter/com- mistors".
pressor".
20
* "Test Run operation" means the
operation within 30 minutes
after the emergency operation
switch is pressed.
If blinking of OPERATION INDI-
CATOR lamp cannot be checked,
it can be checked with failure
mode recall function.
Refer to outdoor unit service manual.
Upper lamp Upper lamp
7-time blink 14-time blink
Cause: or more
Outdoor unit Cause:
• Trouble of Outdoor unit
outdoor con- • Other ab-
trol system. normality
Replace the Check "Flow
inverter P.C. chart of the
board or detailed
the outdoor outdoor unit
electronic failure mode
control P.C. recall func-
board. tion."