Hitachi RAS-3HVRNME-AF, Installation And Operation Manual, Page: 29 / 40

29
PMML0205A rev.4 - 11/2012
ENGLISH
10.6. REFRIGERANT CHARGE AND VACUUM
PROCEDURE

CAUTION:
Do not charge OXYGEN, ACETYLENE, or other flammable
and poisonous gases into the refrigerant cycle when performing
a leakage test or an airtight test. These types of gases
are extremely dangerous and an explosion can occur. It is
recommended that oxygen free nitrogen be charged for these
types of tests cycle.
Charge refrigerant correctly. Overcharging or insufficient charging
could cause a compressor failure.
Check for refrigerant leakage in detail. If a large refrigerant
leakage occurred, it would cause difficulty with breathing or
harmful gases would occur if a fire were being used in the room.
If the flare nut is tigthened too hard, the flare nut may crack after a
long time and cause refrigerant leakage.
1
Connect the gauge manifold using charging hoses with a ni-
trogen cylinder to the check joints of the liquid line and the gas
line stop valves.

IMPORTANT NOTE:
For YUTAKI S80, supply power to the indoor unit and switch
the DSW1-2 ON of its PCB1. Thereby, solenoid valves SV1
and SV2 of the indoor unit will open to allow the operation
of vacuum and refrigerant charge inside the indoor unit. It
is very important to remind to switch the DSW1-2 OFF when
finishing the whole procedure.
2 Check for any gas leakage at the flare nut connection by using
nitrogen gas inside of the field-supplied piping to increase the
pressure at 4.15 MPa.
3
Connect the vacuum pump to the gauge manifold and opera-
te it for 1 to 2 hours until the pressure decreases lower than a
pressure of 756 mmHg in vacuum.
4 Fully open the gas and liquid stop valves.
5 Operate the outdoor unit in cooling operation for more than 10
minutes to circulate the refrigerant through the whole circuit.
Thermal insulation
Gas line
Cover the flare
nut and union
of the piping
connection with
thermal insulation
Liquid line
Liquid stop valve
Gas stop valve
Nitrogen tank
(For air Tight test & Nitrogen
blow during brazing)
Vacuum cylinder
Manifold
gauge
Outdoor unit
Example of Refrigerant Charge.
10.6.1. REFRIGERANT CHARGING qUANTITY
Outdoor unit is factory charged with a refrigerant charge amount
for 30m of piping length. The maximum refrigerant piping length
is 30m so it is not required an additional refrigerant charge.
”
Outdoor unit Factory Refrigerant charge (Wo Kg) is as follows:
O/U MODEL Wo (Kg)
Chargeless
Length
ℓ
(m)
RAS-3HVRNME-AF 2.4 30
RAS-4H(V)RNME-AF 3.9 30
RAS-5H(V)RNME-AF 4.0 30
RAS-6H(V)RNME-AF 4.0 30
10.7. PUMP DOWN REFRIGERANT
When the refrigerant should be collected into the outdoor unit
due to indoor/outdoor unit relocation, collect the refrigerant as
follows:
1. Attach the manifold gauge to the gas and the liquid stop
valves.
2. Turn ON the outdoor unit power source.

IMPORTANT NOTE:
For YUTAKI S80 turn ON the indoor unit power source.
3. Set the DSW1-1 pin of the outdoor unit PCB at the “ON” side
for pump down operation (test run cooling). Close the liquid
stop valve to retain all the refrigerant inside the outdoor unit.
4. When the pressure at lower pressure side (gas stop valve)
indicates -0.01 MPa (-100 mmHg), perform the following
procedures immediately.
−
Close the gas stop valve.
−
Set the DSW1-1 pin at the “OFF” side (To stop the unit
operation).
5. Turn OFF the outdoor unit power source.

CAUTION:
Measure the low pressure by the pressure gauge and keep it not
to decrease than -0.01 MPa. If the pressure is lower than -0.01
MPa, the compressor may be faulty.

IMPORTANT NOTE:
For YUTAKI S80, supply power to the indoor unit and switch
the DSW1-2 ON of its PCB1. Thereby, solenoid valves SV1
and SV2 of the indoor unit will open to allow the operation
of vacuum and refrigerant charge inside the indoor unit. It
is very important to remind to switch the DSW1-2 OFF when
finishing the whole procedure.
REFRIGERANT PIPING &
REFRIGERANT CHARGE