Daikin VRV IV i Series Installation And Operation Manual page 23

Leak test and vacuum drying
Checking the refrigerant piping involves:
▪ Checking for any leakages in the refrigerant piping.
▪ Performing vacuum drying to remove all moisture, air or nitrogen
in the refrigerant piping.
If there is a possibility of moisture being present in the refrigerant
piping (for example, water may have entered the piping), first carry
out the vacuum drying procedure below until all moisture has been
removed.
All piping inside the unit has been factory tested for leaks.
Only field installed refrigerant piping needs to be checked.
Therefore, make sure that all the compressor unit stop valves are
firmly closed before performing leak test or vacuum drying.
NOTICE
Make sure that all (field supplied) field piping valves are
OPEN (not compressor unit stop valves!) before you start
leak test and vacuuming.
For more information on the state of the valves, refer to
"14.3.3 Checking refrigerant piping:
14.3.2 Checking refrigerant piping: General
guidelines
Connect the vacuum pump through a manifold to the service port of
all stop valves to increase efficiency (refer to
Setup" [ 4 23]).
refrigerant piping:
NOTICE
Use a 2-stage vacuum pump with a non-return valve or a
solenoid valve that can evacuate to a gauge pressure of
–⁠ 1 00.7 kPa (−⁠ 1 .007 bar)(5 Torr absolute).
NOTICE
Make sure the pump oil does not flow oppositely into the
system while the pump is not working.
NOTICE
Do NOT purge the air with refrigerants. Use a vacuum
pump to evacuate the installation.
14.3.3 Checking refrigerant piping: Setup
The system contains 2 refrigerant circuits:
▪ Circuit 1: Compressor unit → Heat exchanger unit
▪ Circuit 2: Compressor unit → Indoor units
You have to check both circuits (leak test, vacuuming drying). How
to check depends on your available tools:
If you have a
manifold...
With refrigerant line You can check both circuits at once. To do
splitters so, connect the manifold via the splitters to
both circuits, and check.
Without refrigerant You have to check the circuits separately. To
line splitters do so:
(takes twice as long) ▪ First connect the manifold to circuit 1,
and check.
▪ Then connect the manifold to circuit 2,
and check.
Possible connections:
RKXYQ5T8 + RKXYQ8T7Y1B
VRV IV compressor unit for indoor installation
4P499900-1B – 2021.12
Setup" [ 4 23].
"14.3.3 Checking
Then
Manifold Connections
A
Circuit 1 and 2
p < p >
together
B
f
A
i
N2 R410A
B
g h e
Only circuit 1
A
B
Only circuit 2
A
B
a Liquid line stop valve (circuit 1: to heat exchanger unit)
b Gas line stop valve (circuit 1: to heat exchanger unit)
c Gas line stop valve (circuit 2: to indoor units)
d Liquid line stop valve (circuit 2: to indoor units)
e Vacuum pump
f Pressure reducing valve
g Nitrogen
h Weighing scales
i Refrigerant R410A tank (siphon system)
A, B, C Valves A, B and C
D Refrigerant line splitter
Valve
Valves A, B and C
Liquid line and gas line stop
valves (a, b, c, d)
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
14.3.4 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
–⁠ 1 00.7 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 operation pressure of
the unit, i.e. 4.0 MPa (40 bar).
14 Piping installation
Compressor unit
5 HP
b
a
C
c
D
b
C
C
a c
D
d
d
C
RDXYQ
C
b
8 HP
a
C
b
a
c
C
c
d
C
RDXYQ
State of valve
Open
Close
"14.3.1 About
piping" [ 4 22]).
Installation and operation manual
d
23