Hitachi RAS-5HVRNM1E Service Manual page 72

3 Piping work and
refrigerant charge
1. Stop valve
2. Flare nut
A. Do not apply two spanners at this position. If applied,
leakage will occur
C A U T I O N
– At the test run, fully open the spindle. If not fully
opened, the devices will be damaged.
– Do not attempt to turn service valve rod beyond its
stop.
– Do not loosen the stop ring. If the stop ring is
loosened, it is dangerous since the spindle will hop
out.
– Do not apply force to the spindle valve at the end of
opening (5 Nm or smaller). The back seat
construction.
• Evacuation and refrigerant charge
– Connect the gauge manifold using charging hoses with a vacuum pump or a nitrogen cylinder to the check joints of
the liquid line and the gas line stop valve.
– Check for any gas leakage at the flare nut connection, by using nitrogen gas to increase the pressure at 4.15 MPa
for outdoor units inside of the field-supplied piping.
– Operate the vacuum pump for 1 to 2 hours until the pressure decreases lower than a pressure of 756 mmHg in
vacuum.
– For charging refrigerant, connect the gauge manifold using charging hoses with a refrigerant charging cylinder to
the check joint of the liquid line stop valve.
– Charge the proper quantity of refrigerant according to the piping length (Calculate the quantity of the refrigerant
charge).
– Fully open the gas line stop valve, and slightly open the liquid line stop valve.
– Charge refrigerant by opening the gauge manifold valve.
– Charge the required refrigerant within the difference range of ±0.5 kg by operating the system in cooling.
– Fully open the liquid line stop valve after completing refrigerant charge.
– Continue cooling operation for more than 10 minutes to circulate the refrigerant.
– See the example below.
64
SMGB0060 rev. 1- 12/2010
A
1
2