6 Installation
Installer and user reference guide
21
RXYSCQ4~6TMV1B
VRV IV-S system air conditioner
4P404224-1C – 2019.07
NOTICE
The connections to the indoor units and all indoor units
should also be leak and vacuum tested. Keep any possible
(field supplied) field piping valves open as well.
Refer to the indoor unit installation manual for more details.
Leak test and vacuum drying should be done before the
power supply is set to the unit. If not, see also the flow
chart earlier described in this chapter (see
checking the refrigerant piping" on page 20
6.5.4
To perform a leak test
The leak test must satisfy the specifications of EN378‑2.
To check for leaks: Vacuum leak test
1
Once reached, turn off the vacuum pump and check that the
pressure does not rise for at least 1 minute.
2
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
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 operation pressure of
the unit, i.e. 4.0 MPa (40 bar).
2
Test for leaks by applying a bubble test solution to all piping
connections.
3
Discharge all nitrogen gas.
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).
6.5.5
To perform vacuum drying
NOTICE
The connections to the indoor units and all indoor units
should also be leak and vacuum tested. Keep, if existing,
all (field supplied) field valves to the indoor units open as
well.
Leak test and vacuum drying should be done before the
power supply is set to the unit. If not, see
checking the refrigerant piping" on page 20
for more
information.
To remove all moisture from the system, proceed as follows:
1
Check that, with the vacuum pump turned off, the target
vacuum is maintained for at least 1 hour.
2
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
charge refrigerant" on page 22
for more information.
INFORMATION
After opening the stop valve, it is possible that the pressure
in the refrigerant piping does NOT increase. This might be
caused by e.g. the closed state of the expansion valve in
the outdoor unit circuit, but does NOT present any problem
for correct operation of the unit.
6.6
To insulate the refrigerant piping
After finishing the leak test and vacuum drying, the piping must be
insulated. Take into account the following points:
▪ Make sure to insulate the connection piping and refrigerant branch
kits entirely.
▪ Be sure to insulate the liquid and gas piping (for all units).
▪ Use heat resistant polyethylene foam which can withstand a
temperature of 70°C for liquid piping and polyethylene foam which
can withstand a temperature of 120°C for gas piping.
▪ Reinforce the insulation on the refrigerant piping according to the
installation environment.
▪ If there is a possibility that condensation on the stop valve might
drip down into the indoor unit through gaps in the insulation and
piping because the outdoor unit is located higher than the indoor
unit, this must be prevented by sealing up the connections. See
below figure.
a
b
a
Insulation material
b
Caulking etc.
6.7
Charging refrigerant
6.7.1
About charging refrigerant
The outdoor unit is factory charged with refrigerant, but depending
on the field piping you have to charge additional refrigerant.
Before charging refrigerant
Make sure the outdoor unit's
external
refrigerant piping is checked
(leak test, vacuum drying).
Typical workflow
Charging additional refrigerant typically consists of the following
stages:
1
Determining how much you have to charge additionally.
2
Charging additional refrigerant (pre-charging and/or charging).
3
Filling in the fluorinated greenhouse gases label, and fixing it to
the inside of the outdoor unit.
6.7.2
Precautions when charging refrigerant
INFORMATION
Also read the precautions and requirements in the
following chapters:
▪ General safety precautions
▪ Preparation
WARNING
▪ Only use R410A as refrigerant. Other substances may
cause explosions and accidents.
▪ R410A contains fluorinated greenhouse gases. Its
global warming potential (GWP) value is 2087.5. Do
NOT vent these gases into the atmosphere.
▪ When charging refrigerant, always use protective
gloves and safety glasses.
