5 Installation
Installation and operation manual
11
RKXYQ5T7Y1B
VRV IV compressor unit for indoor installation
4P408443-1 – 2015.07
a
Pressure reducing valve
b
Nitrogen
c
Weighing scales
d
Refrigerant R410A tank (siphon system)
e
Vacuum pump
f
Liquid line stop valve (circuit 2: to indoor units)
g
Gas line stop valve (circuit 2: to indoor units)
h
Gas line stop valve (circuit 1: to heat exchanger unit)
i
Liquid line stop valve (circuit 1: to heat exchanger unit)
A, B, C
Valves A, B and C
D
Refrigerant line splitter
Valve
State of valve
Valves A, B and C
Open
Liquid line and gas line stop
valves (f, g, h, i)
Close
NOTICE
The connections to the indoor units and to the heat
exchanger unit, and all indoor units and the heat
exchanger unit itself 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 10
5.4.4
To perform a leak test
The leak test must satisfy the specifications of EN378‑2.
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) 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
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).
5.4.5
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).
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
compressor unit stop valves, or keep them closed. See
"5.6.3 To charge refrigerant" on page 12
5.5
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.
Ambient
temperature
Humidity
Minimum thickness
≤30°C
75% to 80% RH
15 mm
>30°C
≥80% RH
20 mm
Condensation might form on the surface of the insulation.
▪ If there is a possibility that condensation on the stop valve might
drip down into the indoor unit or into the heat exchanger unit
through gaps in the insulation and piping because the compressor
unit is located higher than the indoor unit or higher than the heat
exchanger unit, this must be prevented by sealing up the
connections. See below figure.
a
b
a
Insulation material
b
Caulking etc.
5.6
Charging refrigerant
5.6.1
Precautions when charging refrigerant
WARNING
▪ Only use R410A as refrigerant. Other substances may
cause explosions and accidents.
▪ R410A contains fluorinated greenhouse gases. Its
global warming potential value is 2087.5. Do NOT vent
these gases into the atmosphere.
▪ When charging refrigerant, always use protective
gloves and safety glasses.
