Collecting Refrigerant For Replacing Indoor Unit - Hitachi FSG Series Service Manual

2
SERVICING
58

2.12 COLLECTING REFRIGERANT FOR REPLACING INDOOR UNIT

1. Prepare an empty refrigerant cylinder at -760mmHg with a
charging hose. Measure the empty cylinder's weight.
2. After shutting the stop valve on the cylinder, connect the
charge hose to the liquid line stop valve.
Connect a pressure gauge to the check joint on the gas line
stop valve.
3. Air purge inside of the hose between the liquid line stop
valve and cylinder by loosening connection of the liquid line
stop valve and close the connecting port of the cylinder
after air purging.
4. Operate the inverter-driven compressor only as cooling
mode by using dip switch, DSW7.
5. Open the liquid line stop valve on the cylinder to collect
refrigerant into it. The cylinder capacity shall be equivalent
to half of the total refrigerant capacity. Check the refrigerant
quantity by measuring the weight.
6. Close the liquid line stop valve on the cylinder gradually
during the cooling operation.
7. Fix the opening of the liquid line stop valve at a slightly
opened position. Continue the cooling operation.
8. Finally close the liquid line stop valve and then gas line
stop valve and stop the units at the same time when the
pressure at the liquid line stop valve reaches at -400mmHg.
NOTES:
The cylinder capacity shall be equivalent to half of the total
refrigerant capacity.
In case of 8HP to 20HP outdoor units;
Operate the inverter-driven compressor only by using the
dip switch, DSW7.
NOTE:
In the case that the collected refrigerant is recharged into
the system, charge it by let the cylinder up side down so
that refrigerant and oil can be charged together.
Hose
Pressure Gage
Gas Line
Liquid Line
Stop Valve
Stop Valve
Connecting
Port
Cylinder