Hitachi RAS-1.5WHVRP2E Bedienungsanleitung Seite 20

• There is no refrigerant in the cycle of the indoor unit.
!
CAUTION
• All external piping shall be selected in size and dimension
avoiding any mechanical strength due to contraction or
expansion, vibration or refrigerant pulsation.
• All the piping shall be protected against any environmental
effect like water freezing, corrosion, etc. When flexible pipe is
used, precautions shall be taken against mechanical damages,
excessive stresses by torsion or any other.
• Flare nut connections shall be accessible for maintenance purposes.
• Ensure that refrigerant piping is earthed prior to units
interconnection and in case of additional refrigerant charging
is required.
6.2 Brazing work
!
CAUTION
• 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.
• Use a reducer valve when nitrogen gas blowing is performed
during brazing. The gas pressure should be maintained within
0.03 to 0.05MPa. If a excessively high pressure is applied to a
pipe, it will cause an explosion.
6.3 Refrigerant charge
!
CAUTION
• 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.
• 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.
6.4 Refrigerant Charging Quantity
In case of the actual piping length (L) is more than the
specified length, the additional refrigerant quantity
should be charged according to the table below:
 Outdoor unit refrigerant charge (kg)
 Chargeless length (m)
 Additional refrigerant charge (g/m)
 Maximum piping length (m)
 Maximum additional charge (kg)
 Maximum total charge (kg)
EN
PMML0640 rev.2 - 11/2024 - 1000019628
10m<L≤30m
 
1.5 HP 1.1 10
2 HP 1.1 10
2.5 HP 1.2 10
3 HP 1.2 10
L>30m
 
1.5 HP 1.1 10
2 HP 1.1 10
2.5 HP 1.2 10
3 HP 1.2 10
1. Determine an additional refrigerant quantity and
charge it into the system.
2. Record the additional refrigerant quantity to facilitate
service activities thereafter.
!
CAUTION
• When charging refrigerant accurately measure refrigerant to
be charged.
• Overcharging or undercharging of refrigerant can cause
compressor trouble.
• Refer to indoor unit installation manual for refrigerant charge
and minimum floor requirements.
• When the pressure is measured, use the check joints of the gas
stop valve and liquid stop valve.
• 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.
Cooling operation Heating operation
Check joint for gas
Low pressure
stop valve
Check joint for Exclusive for vacuum pump and
liquid stop valve
• Be careful that refrigerant and oil do not splash to the electrical
parts at removing the charge hoses.
   
15 30 0.3 1.4
15 30 0.3 1.4
15 30 0.3 1.5
15 30 0.3 1.5
   
15 50 0.6 1.7
15 50 0.6 1.7
30 40 0.9 2.1
30 40 0.9 2.1
High pressure
refrigerant charge
Stop valve (liquid)
Stop valve (gas)
6