Checking Refrigerant Piping: General Guidelines; Checking Refrigerant Piping: Setup; To Perform A Leak Test; To Perform Vacuum Drying - Daikin LRMEQ3BY1 Installation And Operation Manual

5 Installation
5.4.2 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 14).
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.
5.4.3

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
Valve
Valve A
Valve B
Valve C
Liquid line stop valve
Gas line stop valve
NOTICE
Indoor units should also be leak and vacuum tested. Keep
any possible (field supplied) field piping valves open as
well.
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
–⁠ 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 Break the vacuum by pressurising with nitrogen gas to a
minimum gauge pressure of 0.2 MPa (2 bar).
Installation and operation manual
14
"5.4.3 Checking
State of valve
Open
Open
Open
Close
Close
▪ Never set the gauge pressure of the high pressure section
of the system higher than the maximum operation pressure
of 4.0 MPa (40 bar).
▪ Never set the gauge pressure of the low pressure section
of the system higher than the design pressure of the indoor
unit.
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
–⁠ 1 00.7 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 service port of the liquid stop valve, or
first pre-charge a portion of refrigerant through the liquid line,
either open the outdoor unit stop valves, or keep them closed.
See "5.5.3 To charge refrigerant" on page 15
information.
5.5

Charging refrigerant

5.5.1

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 (GWP) value is 2087.5. 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.
NOTICE
Before starting charging procedures, check if the 7‑LEDs
display is as normal (see
page 21). If a malfunction code is present, see
"8.1 Solving problems based on error codes" on
for more
"6.1.4 To access mode 1 or 2" on
page 24.
LRMEQ3+4BY1
Air-cooled refrigeration condensing unit
4P495373-1 – 2017.07