Hitachi RAS-10HRNM, Service Manual, Page: 467 / 482

12.2 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.
12 Maintenace notes
459
SMGB0060 rev. 1- 12/2010
12