To Perform Vacuum Drying; To Insulate The Refrigerant Piping; Charging Refrigerant; Precautions When Charging Refrigerant - Daikin RXYTQ8T7YF Installer And User Manual

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.
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 21
information.
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).
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
outdoor unit stop valves, or keep them closed. See
charging refrigerant" on page 24
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:
▪ 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 Humidity
temperature
≤30°C 75% to 80% RH
>30°C ≥80% RH
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.
RXYTQ8~16T7YF
VRV IV system air conditioner
4P388989-1B – 2016.02
"6.5.1 About
for more
"6.7.2 About
for more information.
Minimum thickness
15 mm
20 mm
b
a
a Insulation material
b Caulking etc.
6.7

Charging refrigerant

6.7.1

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
In case of a multiple outdoor system, turn on the power of
all outdoor units.
NOTICE
Be sure to turn on the power 6 hours before operation in
order to have power running to the crankcase heater and
to protect the compressor.
NOTICE
If operation is performed within 12 minutes after the indoor
and outdoor units are turned on, the compressor will not
operate before the communication is established in a
correct way between outdoor unit(s) and indoor units.
NOTICE
Before starting charging
7‑segment display indication of the outdoor unit A1P PCB
is as normal (see "7.2.4 To access mode 1 or 2" on
page 32). If a malfunction code is present, see
"10.2 Solving problems based on error codes" on
page 41.
NOTICE
Make sure all connected indoor units are recognised (see
[1‑10] in "7.2.7 Mode 1: Monitoring settings" on
NOTICE
Close the front panel before any refrigerant charge
operation is executed. Without the front panel attached the
unit cannot judge correctly whether it is operating properly
or not.
6 Installation
procedures, check if the
page 33).
Installer and user reference guide
23