11 Maintenance notes
General notes
SMGB0091 rev.2 - 11/2015
284
11.1 General notes
11.1.1 Checking the power source and the wiring connection
Check the following items in the case of abnormal operation:
No.
Check item
Procedure
1
Is the breaker of the fuse cut
out?
Check the secondary voltage of the breaker and the fuse by means of a tester.
2
Is the secondary power
source on the transformer
correct?
Disconnect the secondary side of the transformer and check the voltage by means of a tester.
Primary side 220,
230 or 240 V
Circuit
and
voltage
Secondary
side
Indoor unit
transformer
12 V
12 V
3
Is the wiring loosened or
incorrectly connected?
Check the wiring connection on the PCB.
•
Thermistor connectors
•
Connector of the remote control cable
•
Connector of the transformer
•
Each connector in a high-voltage circuit
Check the connectors according to the electrical wiring diagram.
11.1.2
Burnt-out compressor due to an insufficient refrigerant charge
Question and answer for the field work:
Example 1: Burnt-out compressor due to an insufficient refrigerant charge
Phenomenon
After commissioning, the alarm code "08" sometimes occurred and the compressors were burnt out after
operating for two months.
Cause
The refrigerant piping work was performed during the summer season. The additional refrigerant was not
sufficiently charged from the discharge gas side.
This insufficient refrigerant charge resulted in the overheating of the discharge gas and the oil deterioration,
which was finally due to the separated operation despite the alarm code "08".
Countermeasure
1
The compressor was replaced with a new compressor.
2
The correct refrigerant amount was charged according to the refrigerant piping length and the connected
indoor units.
Remarks
Additional refrigerant charge: Open the liquid stop valves slightly when you charge the additional refrigerant
from the check joint of the liquid stop valves (the discharge gas side) during the cooling process. If the liquid
stop valve is fully open, it is difficult to charge the additional refrigerant. Do not charge the refrigerant from the
gas stop valve.