Mitsubishi Heavy Industries SRRM40HENG-L, Handbook, Page: 1089 / 1106

1087
FDC-HKXR
Is the 52C turned ON?
Can the compressor
operate?
Does the LD1 (green) on
the inverter PCB blink?
Do voltage appear at
the 52C coil?
Defective outdoor PCB
Defective inverter PCB
Turn on the SW
3-4
on the outdoor unit PCB
(See page 1075)
Can the
compressor operate
Does a voltage
appear at U.V and W of
the compressor?
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
Defective inverter PCB
Defective 52C
→
Replacement
Continued from
the next page
• Is the indoor unit suction thermistor
nomal?
• Doesn't the thermistor stop?
(See page 1091)
Turn off the SW
3-4
on the outdoor unit PCB
Turn on the 52C forcedly
(Manual operation)
Defective compressor
Defective outdoor unit
control PCB
(See page 1091)
Full load to command an unconditonal
35Hz operation from the inverter PCB
Strap the connector Cn
15
on the inverter
PCB (1)
(3) When the remote controller indication is nomal but the compressor cannot operate:
(No check indication)
• Give instructions so that the requested best frequency may be output,
irrespective of the thermostat condition, from outdoor to indoor. A ccord-
ingly, if the indoor/outdoor transmission is faulty, the compressor cannot
operate.
• When the SW
3-4
is turned on, error indication is not provided if the indoor
unit is not connected.
At remote controller operation, check if E3 (no mate) or E5 (transmission
error) is indicated.
Notes (1) The expansion valve of the indoor unit may be closed or the indoor unit fan may stop. After the compressor is operated, stop it at once.
Otherwise, this will cause a failure to the compressor.
(2) The next page shows a checking procedure using only the outside unit.