Alarm code
53
Inverter error signal detection.
•
The RUN indicator flashes and the ALARM indication is displayed on the remote control switch.
•
The unit no., the alarm code and the unit code are alternatively displayed in the temperature setting section and the unit
no. and alarm code are displayed on the outdoor unit's PCB1 display.
* The IPM (Transistor module) has detecting function of abnormality.
This alarm is indicated when the transistor module detects the anomaly seven times in thirty minutes (retry operation
is carried out up to sixth times).
Activation conditions:
Abnormal current to the transistor module, such as a short-circuit or earth leakage, or
Abnormal temperature in the transistor module, or
Decrease in control voltage.
Yes
Yes
Faulty
Turn off power, disconnect
U, V, W from compressor
terminals and restart.
Does the protecting function
activate? *3)
Check the transistor
module. *1) *2)
Normal
No
Is the heat exchanger of
outdoor unit clogged?
Replace the PCB2.
Remove clogging or
replace the heat exchanger.
Replace the transistor module.
Check the compressor.
Check the compressor.
Check fan motor.
Yes
Yes
Is the silicon grease coated all over
between the transistor module and the
radiated fin?
Is the fixed screw on the transistor
module loose?
No
No
No
Coat the silicon grease to all
the touched face between
the transistor module and the
radiated fin fully. Fix the
screw correctly.*4)
Check the PCB2.
Check the compressor.
Normal
Normal
Replace the PCB2 and
the transistor module.
Failure of PCB2.
Replace the PCB2.
Check pressure and
refrigerant cycle.
Connect power line
to CT (Current Transformer).
Is high pressure increased?
Check clogging for
heat exchanger.
Yes
(It trips immediately.)
No (It trips after a certain period.)
Restart operation.
Does it trip soon?
Is power line is
connected to CT?
Abnormal
Abnormal
(Itc=1, 12)
(Itc=21)
PCB1: Control PCB in Outdoor Unit
PCB2: Inverter PCB
*1): Carry out the electrical discharge when Inverter parts are checked or replaced, refer to
, see on page 267
.
*2): Regarding the method for checking the transistor module, refer to:
Checking procedures for other main parts
, see on
page 267
.
*3): Place contact 1 of DSW1 on PCB2 to the ON position when restarting with the compressor terminals disconnected.
After troubleshooting, place contact 1 of DSW1 on PCB2 to the OFF position.
8 Troubleshooting
223
SMGB0065 rev. 1 - 12/2010
8