Mitsubishi Heavy Industries SRK25GZ-L1 Handbook page 361

(b) Inspection method when there are fault lamps (outdoor unit LED)
1
Open phase at L phase (Primary side)
3
Outdoor unit
Red LED 1 time flash
Green LED Stays OFF
2
Overcurrent of the compressor motor
Outdoor unit
Red LED 2 time flashes
Green LED Stays OFF
Power supply
checked at - ,
L L L
1 2
or - phase of 52C
L L
2 3
secondary side?
YES
Compressor
overcurrent?
NO
Defective outdoor unit PCB
Replacement (Defective
CT input circuit)
3
The wiring (secondary wiring of 52C) to the compressor is open.
Outdoor unit
Red LED 3 time flashes
Green LED Stays OFF
52C secondary side
or phase open?
L L
2 3
NO
Defective outdoor unit PCB
Replacement
(Defective CT circuit)
Defective outdoor unit PCB
- NO
• 3 Phase: Open phase at
L
1 3
or phase
L
2
• Is the power supply voltage correct
(not too low)?
(1)
• Are the power supply wires appro-
YES
priate (not too thin)?
• Is the overcurrent setting correct
(SW3 setting)?
• Is not it operated under overload?
(1)
YES
Repair
(2)
Is phase at
YES
L
3
primary side at open
phase
NO
Replacement
• Defective 52C
L
• 3 phase: Broken wire at
1
phase between 52C ~ CM or
TB ~ 52C
1
Note (1) Measure and check the current value.
Confirm that the overcurrent setting by SW
unit PCB is correct.
Notes (1) When voltage is detected at 52C primary side
phase but not at the secondary side, check also 52C (bro-
ken coil, poor contact).
(2) When voltage is detected at 52C primary side
phase and there is no error at 52C (52C is energized if TB
or
L
2
are short circuited), the outdoor unit PCB (defective X
circuit or X
circuit) is defective.
FDT ( N ) -H
Correction
or
L L
1 2
Inspect at the unit side.
• During cooling: Is FM operating?
0
• At heating:
Is FM operating?
1
Is the service valve (gas side) opened
fully?
Is the filter clogged?
• Is it overcharged?
• Is the installation space of indoor
outdoor unit adequate?
• Is there any short circuit on the indoor/
outdoor unit?
3
terminal and 52C coil secondary side connector
L
3
) or indoor unit PCB (defective thermostat
01
of outdoor
or
L L
2 3
or
L L
2 3
1
01
359