Hitachi RAS-(4-12)HRNM(2)(E) - Burnt-Out Compressor Due to an Insufficient Refrigerant Charge

12 Maintenace notes
463
SMGB0064 rev.0 - 08/2011
12
12.2 Burnt-out compressor due to an insufcient refrigerant charge
Question and answer for the eld work
Example 1: Burnt-out compressor due to an insufcient 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 sufciently
charged from the discharge gas side.
This insufcient refrigerant charge resulted in the overheating of the discharge gas and the oil deterioration which was
nally 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 difcult to charge the additional refrigerant. Do not charge the refrigerant from the gas stop valve.