Refrigerant Charge - Hitachi RAS-4FSN3E Manuel D'utilisation

REFRIGERANT PIPING & REFRIGERANT CHARGE

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 CHARGE AMOUNT
Although refrigerant has been charged into this unit, additional
refrigerant charge is required according to piping length.
• The additional refrigerant quantity should be determined
and charged into the system according to the following
procedure.
• Record the additional refrigerant quantity in order to facilitate
maintenance and servicing activities.

Refrigerant charge before shipment (W
W is the outdoor unit refrigerant charge before shipment
0
(Factory charge), and it's shown in the following table:
Model
RAS-(4/5/6)FS(V)N(Y)3E
!
C A U T I O N
• When charging refrigerant, measure the amount precisely.
• Overcharging or undercharging of refrigerant may cause compressor
problems.

Additional refrigerant charge calculation
method
Calculate the additional refrigerant charge amount (Additional
charge) according to the following steps:
10 PMML0389B rev.1 - 07/2016
Cooling Heating
operation operation
Low pressure High pressure
Exclusive for vacuum pump
High pressure Low pressure
(kg))
0
Refrigerant charge before shipment
(W (kg))
0
3.6
• 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.
Step 1: Additional refrigerant charge calculation for
liquid piping (W (kg))
1
The additional refrigerant charge must be calculated by
multiplying the total piping length of each diameter per its
calculation factor according to the following table. The result is
the additional refrigerant charge for liquid piping.
Additional refrigerant charge factor
Pipe size (mm)
Ø9.52
Ø6.35
Step 2: Charging work
Charge refrigerant (R410A) into the system according to the
instructions in the Service Manual.
Step 3: Total refrigerant charge of the system
(W (kg))
TOT
The total refrigerant charge (Total charge) of this system is
calculated by the following formula:
W
TOT
System example (W ) =
TOT
W is the outdoor unit refrigerant charge before shipment
0
explained before, and it's shown in its specific table.
(kg/m)
x 0.05
x 0.02
= W + W
0
+ = kg