Field Work Instruction; Burnt-Out Compressor Due To Insufficient Refrigerant Charge; Insufficient Cooling Performance When A Long Piping Is Applied - Hitachi FSG Series Service Manual

5. FIELD WORK INSTRUCTION

5.1.

BURNT-OUT COMPRESSOR DUE TO INSUFFICIENT REFRIGERANT CHARGE

n Question and Answer for Field Work
Example 1: Burnt-out Compressor due to Insufficient Refrigerant Charge
Phenomenon
Cause
Countermeasure
Remarks
5.2.

INSUFFICIENT COOLING PERFORMANCE WHEN A LONG PIPING IS APPLIED

n Question and Answer for Field Work
Example 2: insufficient Cooling Performance When a Long Piping is Applied
Phenomenon
Cause
Countermeasure
Remarks
After commissioning, alarm code "08" sometimes occurred and compressors were burnt out
after 2 month operation.
Refrigerant piping work was performed during summer season. Additional refrigerant was not
sufficiently charged from the discharge side.
This insufficient refrigerant charge resulted in discharge gas overheating and oil deterioration
finally due to separated operation despite "08" alarm.
1. The compressor was replaced with a new one.
2. Correct refrigerant amount was charged according to refrigerant piping length and
connected indoor units.
Additional Refrigerant Charging: Open the liquid stop valve slightly when the additional
refrigerant is charged from the check joint of the liquid stop valve (discharge side) during the
cooling operation. If the liquid valve is fully open, it is difficult to charge the additional
refrigerant. Do not charge refrigerant from the gas stop valve.
Sufficient Cooling was not available for an Indoor Unit which located at the farthest position.
In the case that an Outdoor Unit is Located 20 meters lower than Inddoor Units, reseting of
the dip switch, DSW3 is required.
However, no setting was performed. Therefore, the largest discharge pressure was not
increased, resulting in insufficient cooling performance for the Indoor.
Insufficient
Cooling
Setting for DSW3 was Changed
Pay a sepecial attention to the liquid pipe size if the lift between ther Indoor Units and
Outdoor Units is higher than 20 meters. For details, see the "Piping Work in TC"
FIELD WORK INSTRUCTION
I.U
O.U
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DSW3