Hitachi RAS-2WHVRP Instruction Manual page 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.
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.
8.5 REFRIgERANT ChARgINg QUANTITY
In case of the actual piping length is more than the specified length, the additional refrigerant quantity should be charged according
to the table below:
RAS-2WHVRP
RAS-2.5WHVRP
RAS-3WHVRP
1 Determine an additional refrigerant quantity 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.
• Refer to indoor unit installation manual for refrigerant charge and minimum floor requirements.
8.6 CAUTION OF ThE PRESSURE BY ChECK jOINT
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.
Check joint for gas stop valve
Check joint for liquid stop valve
10 PMML0509 rev.0 - 02/2019
Outdoor unit refrigerant
Chargeless length (m)
charge (kg)
1.2
1.3
1.3
Cooling heating
operation operation
Low pressure High pressure
Exclussive for vacuum pump
and refrigerant charge
• 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.
• 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 tigthened too hard, the flare nut may crack after a
long time and cause refrigerant leakage.
Additional refrigerant
charge (P) (g/m)
15
15
10
<30m: 15
>30m : 40
?
N O T E
Be careful that refrigerant and oil do not splash to the electrical parts at
removing the charge hoses.
Max additional charge
(kg)
0.6
0.6
<30m= 0.6
>30m=1.6
Stop valve (liquid)
Stop valve (gas)