Hitachi UTOPIA R32 Series Installation And Operation Manual page 54

✓ Charge the proper quantity of refrigerant according to the piping length (Calculate the
quantity of the refrigerant charge). Charged quantity needs to be controlled by a weighing
equipment.
✓ Charge refrigerant by opening the gauge manifold valve. Charge the required refrigerant by
operating the system in cooling.
✓ With the gas line stop valve fully open, slightly open the liquid line stop valve.
✓ Operate the compressor at the cooling mode. At this time, liquid valve is slightly opened.
Continue cooling operation for more than 10 minutes to circulate the refrigerant.
✓ Fully open the gas valve and liquid valve.
!
CAUTION
• If the total refrigerant amount is excessive or insufficient, the compressor will be damaged.
• Be sure to charge the refrigerant in the liquid condition.
• The additional refrigerant charge must be performed from the check joint of the liquid valve. If
the additional refrigerant is charged from the check joint of the gas valve, the compressor will
be damaged.
• Insulate the liquid pipe for prevention of the capacity decrease according to the ambient air
conditions and the dewing on the pipe surface by the low pressure. Insulate the flare nut and
union of the piping connection.
• Check for refrigerant leakage in detail to ensure that there is no gas leakage. When large
amount of the refrigerant leaks, the troubles as follows may occur.
✓ Oxygen deficiency: it will cause difficulty with breathing or harmful gases would occur.
✓ Generation of harmful gas due to chemical reaction with fire.
• An excess or a shortage of refrigerant is the main cause of trouble to the units. Charge the
correct refrigerant quantity according to the description of label at the inside of service cover.
• Never use the refrigerant charged in the outdoor unit for air purging. If used, insufficient
refrigerant will lead to failure.
PMEN0654 rev.0 - 12/2023
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