Mitsubishi Electric Mr. SLIM PCA-M71HA2 Service Manual page 17

9-4. TROUBLESHOOTING BY INFERIOR PHENOMENA
Phenomena
(1) LED2 on indoor controller board
is off.
OCH753A
Note: Refer to the manual of outdoor unit for the detail of remote controller.
Cause
• When LED1 on indoor controller board is also off.
Power supply of rated voltage is not supplied to
outdoor unit.
Defective outdoor controller circuit board
Power supply of 220–240 V is not supplied to
indoor unit
Defective indoor power board
Defective indoor controller board
(For the separate indoor/outdoor unit power
supply system)
Power supply of 220–240 VAC is not supplied to
indoor unit.
The connectors of the optional replacement kit are
not used.
Defective indoor controller board
Defective indoor power board
• When LED1 on indoor controller board is lit.
Mis-setting of refrigerant address for outdoor unit
(There is no unit corresponding to refrigerant
address "0".)
17
Countermeasure
Check the voltage of outdoor power
supply terminal block (L, N) or (L3, N).
• When 220–240 VAC is not detected, check
the power wiring to outdoor unit and the
breaker.
• When 220–240 VAC is detected, check
(below).
Check the voltage between outdoor
terminal block S1 and S2.
• When 220–240 VAC is not detected,
check the fuse on outdoor controller circuit
board. Check the wiring connection.
• When 220–240 VAC is detected, check
(below).
Check the voltage between indoor terminal block
S1 and S2.
• When 220–240 VAC is not detected, check
indoor/outdoor unit connecting wire for mis-
wiring.
• When 220–240 VAC is detected, check
(below).
Check voltage output from CN2S on indoor
power board (13.1 VDC). Refer to "9-7-1.
Power board".
• When no voltage is output, check the wiring
connection.
• When output voltage is between 12.5 VDC
and 13.7 VDC, check (below).
Check the wiring connection between indoor
controller board and indoor power board. Check
the fuse on indoor controller board. If no problems
are found, indoor controller board is defective.
Check the voltage of indoor power supply ter-
minal block (L,N).
• When 220–240 VAC is not detected,
check the power supply wiring.
• When 220–240 VAC is detected, check
(below).
Check that there is no problem in the method
of connecting the connectors.
• When there are problems in the method
of connecting the connectors, connect the
connector correctly referring to installation
manual of an optional kit.
• When there is no problem in the method of
connecting the connectors, check
Check voltage output from CNDK on indoor
controller board.
• When 220–240 VAC is not detected, check
the fuse on indoor controller board.
Check the wiring connection between indoor
power supply terminal block and CND on
indoor controller board.
• When 220–240 VAC is detected, check
(below).
Check voltage output from CN2S on indoor
power board.
• When no voltage output, check the wiring
connection between CNDK on indoor control-
ler board and CNSK on indoor power board.
If no problems are found, indoor power board
is defective.
• When 12.5–13.7 VDC is detected, check the
wiring connection between CN2S on indoor
power board and CN2D on indoor power
board.
If no problems are found, indoor controller
board is defective.
Reconfirm the setting of refrigerant address for
outdoor unit.
Set the refrigerant address to "0".
(For grouping control system under which 2 or
more outdoor units are connected, set one of
the units to "0".)
Set refrigerant address using SW1 (3-6) on
outdoor controller circuit board.
(below).