Mitsubishi Heavy Industries SRK25GZ-L1 Handbook page 1089

(3) When the remote controller indication is nomal but the compressor cannot operate:
(No check indication)
Turn on the SW on the outdoor unit PCB
3-4
(See page 1075)
Is the 52C turned ON?
Can the compressor
operate?
Continued from
the next page
Does the LD1 (green) on
the inverter PCB blink?
Turn off the SW on the outdoor unit PCB
3-4
Strap the connector Cn
PCB (1)
Turn on the 52C forcedly
(Manual operation)
Can the
compressor operate
Does a voltage
appear at U.V and W of
the compressor?
Defective compressor
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.
NO
Do voltage appear at
YES
Defective outdoor PCB
YES
• Is the indoor unit suction thermistor
NO nomal?
• Doesn't the thermistor stop?
NO
Defective inverter PCB
YES
on the inverter
15
Full load to command an unconditonal
35Hz operation from the inverter PCB
YES
Defective outdoor unit
control PCB
NO
NO
Defective inverter PCB
YES
• 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 is turned on, error indication is not provided if the indoor
3-4
unit is not connected.
At remote controller operation, check if E3 (no mate) or E5 (transmission
error) is indicated.
YES
the 52C coil?
NO
(See page 1091)
(See page 1091)
FDC-HKXR
Defective 52C → Replacement
1087