14 Charging refrigerant
Installation and operation manual
28
RXYSA4~6A7V/Y1B
VRV 5-S system air conditioner
4P600329-1A – 2020.01
▪ Mount the refnet joint so that it branches either horizontally or
vertically.
▪ Mount the refnet header so that it branches horizontally.
A
B
±
3
0°
a
b
c
a
a
Horizontal surface
b
Refnet joint mounted vertically
c
Refnet joint mounted horizontally
13.3
Checking the refrigerant piping
13.3.1
Checking refrigerant piping: Setup
p< p>
N2
C
b
c
e
a
g
f
d
A
B
R32
a
Pressure reducing valve
b
Nitrogen
c
Weighing scales
d
Refrigerant R32 tank (siphon system)
e
Vacuum pump
f
Liquid line stop valve
g
Gas line stop valve
A
Valve A
B
Valve B
C
Valve C
Valve
State of valve
Valve A
Open
Valve B
Open
Valve C
Open
Liquid line stop valve
Close
Gas line stop valve
Close
NOTICE
Indoor units should also be leak and vacuum tested. Keep
any possible (field supplied) field piping valves open as
well.
13.3.2
To perform a leak test
To check for leaks: Vacuum leak test
1
Evacuate the system from the liquid and gas piping to
–100.7 kPa (–1.007 bar)(5 Torr absolute) for more than 2 hours.
2
Once reached, turn off the vacuum pump and check that the
pressure does not rise for at least 1 minute.
3
Should the pressure rise, the system may either contain
moisture (see vacuum drying below) or have leaks.
To check for leaks: Pressure leak test
1
Test for leaks by applying a bubble test solution to all piping
connections.
2
Discharge all nitrogen gas.
3
Break the vacuum by pressurising with nitrogen gas to a
minimum gauge pressure of 0.2 MPa (2 bar). Never set the
gauge pressure higher than the maximum working pressure of
the unit, i.e. 3.52 MPa (35,2 bar).
NOTICE
Make sure to use a recommended bubble test solution
from your wholesaler. Do not use soap water, which may
cause cracking of flare nuts (soap water may contain salt,
which absorbs moisture that will freeze when the piping
gets cold), and/or lead to corrosion of flared joints (soap
water may contain ammonia which causes a corrosive
effect between the brass flare nut and the copper flare).
13.3.3
To perform vacuum drying
To remove all moisture from the system, proceed as follows:
1
Evacuate the system for at least 2 hours to a target vacuum of
–100.7 kPa (–1.007 bar)(5 Torr absolute).
2
Check that, with the vacuum pump turned off, the target
vacuum is maintained for at least 1 hour.
3
Should you fail to reach the target vacuum within 2 hours or
maintain the vacuum for 1 hour, the system may contain too
much moisture. In that case, break the vacuum by pressurising
with nitrogen gas to a gauge pressure of 0.05 MPa (0.5 bar)
and repeat steps 1 to 3 until all moisture has been removed.
4
Depending on whether you want to immediately charge
refrigerant through the refrigerant charge port or first pre-charge
a portion of refrigerant through the liquid line, either open the
outdoor unit stop valves, or keep them closed. See
29] for more information.
13.3.4
To check for leaks after charging
refrigerant
After charging refrigerant in the system an additional leak test must
be performed. Refer to
"14.6 To check for refrigerant leaks after
31].
14
Charging refrigerant
14.1
Precautions when charging
refrigerant
WARNING
▪ Only use R32 as refrigerant. Other substances may
cause explosions and accidents.
▪ R32 contains fluorinated greenhouse gases. Its global
warming potential (GWP) value is 675. Do NOT vent
these gases into the atmosphere.
▪ When charging refrigerant, ALWAYS use protective
gloves and safety glasses.
NOTICE
If the power of some units is turned off, the charging
procedure cannot be finished properly.
