Checking Refrigerant Piping: General Guidelines; Checking Refrigerant Piping: Setup; To Perform A Leak Test; To Perform Vacuum Drying - Daikin RXYSQ6T7Y1B9 Installer's Manual

6 Installation
NOTICE
Make sure that all indoor units connected to the outdoor
unit are powered on.
NOTICE
Wait until the outdoor unit has finished the initialisation to
apply setting [2‑21].
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 outdoor 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 outdoor unit stop valves!) before you start leak
test and vacuuming.
For more information on the state of the valves, refer to
"6.5.3 Checking refrigerant piping: Setup" on
6.5.2 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
refrigerant piping: Setup" on page 20).
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 (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.
6.5.3

Checking refrigerant piping: Setup

p < p >
A B
g
f
a
d C
N2
b c e
a Pressure reducing valve
b Nitrogen
c Weighing scales
d Refrigerant R410A 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
Installer and user reference guide
20
Valve A
Valve B
Valve C
Liquid line stop valve
Gas line stop valve
6.5.4
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
2 Once reached, turn off the vacuum pump and check that the
3 Should the pressure rise, the system may either contain
page 20.
To check for leaks: Pressure leak test
1 Break the vacuum by pressurising with nitrogen gas to a
"6.5.3 Checking
2 Test for leaks by applying a bubble test solution to all piping
3 Discharge all nitrogen gas.
6.5.5
To remove all moisture from the system, proceed as follows:
1 Evacuate the system for at least 2 hours to a target vacuum of
2 Check that, with the vacuum pump turned off, the target
Valve
Open
Open
Open
Close
Close
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

To perform a leak test

–⁠ 1 00.7 kPa (–⁠ 1 .007 bar/5 Torr) for more than 2 hours.
pressure does not rise for at least 1 minute.
moisture (see vacuum drying below) or have leaks.
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).
connections.
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).

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 19
information.
–⁠ 1 00.7 kPa (–⁠ 1 .007 bar/5 Torr).
vacuum is maintained for at least 1 hour.
State of valve
"6.5.1 About
page 19).
"6.5.1 About
for more
RXYSQ6T7Y1B9
VRV IV-S system air conditioner
4P404677-1A – 2016.03