Hitachi UTOPIA ES Serie Bedienungsanleitung Seite 22

REFRIGERANT PIPING & REFRIGERANT CHARGE
8.3 BRAZING WORK
!
C A U T I O N
• Use nitrogen gas for blowing during pipe brazing. If oxygen, acetylene
or fluorocarbon gas is used, it will cause an explosion or poisonous
gas.
• A lot of oxidation film will occur inside of tubes if no nitrogen gas
blowing is performed during brazing work. This film will be flecked
off after operation and will circulate in the cycle, resulting in clogged
expansion valves, etc. This will cause bad influence to the compressor.
8.4 REFRIGERANT CHARGE
!
C A U T I O N
• Do not charge OXYGEN, ACETYLENE, or other flammable and
poisonous gases into the refrigerant because an explosion can occur.
It is recommended that oxygen free nitrogen be charged for these
types of tests cycle when performing a leakage test or an airtight test.
These types of gases are extremely dangerous,
• Insulate the unions and flare-nuts at the piping connection part
completely.
• Insulate the liquid piping completely to avoid a decrease of
performance; if not, it will cause sweating on the surface of the pipe.
8.5 CAUTION OF THE PRESSURE BY CHECK JOINT
When the pressure is measured, use the check joint of gas stop
valve (A), and use the check joint of liquid piping (B) in the figure
below.
At that time, connect the pressure gauge according to the
following table because of high pressure side and low pressure
side changes by operation mode.
Check Joint for Gas Stop Valve "A"
Check Joint for Piping "B"
Check Joint for Liquid Stop Valve
"C"
8.6 REFRIGERANT CHARGING QUANTITY
Outdoor Units has been charged with refrigerant for 30m
of actual piping length. An additional refrigerant charged is
required in systems with actual piping length longer than 30m.
1 Determine an additional refrigerant quantity according to the
following procedure, and charge it into the system.
2 Record the additional refrigerant quantity to facilitate service
activities thereafter.
!
C A U T I O N
• When charging refrigerant accurately measure refrigerant to be
charged.
• Overcharging or undercharging of refrigerant can cause compressor
trouble. In case of actual piping length less than 5 m, consult your
distributor.
W (kg) is the outdoor unit refrigerant charge before shipment
0
explained before, and it's shown in the following table:
12 PMML0396B rev.0 - 11/2015
Cooling Heating
Operation Operation
Low Pressure High Pressure
High Pressure Low Pressure
Exclusive for Vacuum Pump
and Refrigerant Charge
• Use a reducer valve when nitrogen gas blowing is performed during
brazing. The gas pressure should be maintained within 0.03 to 0.05
MPa. If a excessively high pressure is applied to a pipe, it will cause
an explosion.
• 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 tightened too hard, the flare nut may crack after a
long time and cause refrigerant leakage.
?
N O T E
Be careful that refrigerant and oil do not splash to the electrical parts at
removing the charge hoses.
When the cap is removed,
obscure sound may be
heard because the gas
trapped at O-ring thread
face is released. However,
this is not gas leakage.
Refrigerant charge before
Model
shipment (W
RAS-8HRNSE
RAS-10HRNSE
Setting of Pipe Length DSW
DSW2 setting will be required only when the refrigerant pipe
length is shorter than 5 m or longer than 30 m. Pipe length
setting shall be performed as shown below.
(The  side in the table below shows the DSW location)
DSW2 on Outdoor PCB1
Factory setting Factory setting
Pipe Length 5 m or
Additional refrigerant
(kg)) charge (P) (g/m)
0
6.0 65
6.2 120
Factory setting
Pipe Length 30 m or
shorter longer