To Perform Vacuum Drying; To Insulate The Refrigerant Piping; Charging Refrigerant; About Charging Refrigerant - Daikin LRMEQ4BY1 Installer And User Manual

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).
▪ 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).
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.
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 "6.7.4 To charge refrigerant" on page 22
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:
LRMEQ+LRLEQ3+4BY1
Air-cooled refrigeration condensing unit
4P500362-1A – 2018.09
▪ Make sure to insulate the connection piping and refrigerant piping
branching entirely.
▪ Be sure to insulate the liquid and gas piping (for all units).
▪ Take the following into account when determining the insulation
thickness:
Liquid pipe minimum temperature
Gas pipe minimum temperature
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 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
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
for more
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.
6 Installation
LRMEQ*
5°C
–20°C
b
a
Insulation material
Caulking etc.
Installer and user reference guide
LRLEQ*
0°C
–45°C
21