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14 Piping installation
NOTICE
ALWAYS use a recommended bubble test solution from
your wholesaler.
NEVER use soap water:
▪ Soap water may cause cracking of components, such
as flare nuts or stop valve caps.
▪ Soap water may contain salt, which absorbs moisture
that will freeze when the piping gets cold.
▪ Soap water contains ammonia which may lead to
corrosion of flared joints (between the brass flare nut
and the copper flare).
14.3.5
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 refrigerant charge port or first pre-charge
a portion of refrigerant through the liquid line, either open the
compressor unit stop valves, or keep them closed. See
refrigerant" [ 4 25] for more information.
"14.4.3 To charge
14.3.6
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
▪ If there is a possibility that condensation on the stop valve might
drip down into the indoor unit or into the heat exchanger unit
through gaps in the insulation and piping because the compressor
unit is located higher than the indoor unit or higher than the heat
exchanger unit, this must be prevented by sealing up the
connections. See below figure.
Installation and operation manual
24
14.4
14.4.1
Minimum thickness
15 mm
20 mm
14.4.2
Formula:
R=[(X
a
Insulation material
b
Caulking etc.
Charging refrigerant
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
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
compressor unit, heat exchanger unit and indoor units are
turned on, the compressor will not operate before the
communication is established in a correct way between the
compressor unit, heat exchanger unit and indoor units.
NOTICE
Before starting charging procedures:
▪ In case of 5 HP: Check if the 7‑LEDs display is as
normal (see
"16.1.4 To access mode 1 or
and there is no malfunction code on the user interface
of the indoor unit. If a malfunction code is present, see
"19.1 Solving problems based on error
▪ In case of 8 HP: Check if the 7‑segment display
indication of the compressor unit A1P PCB is as normal
(see
"16.1.4 To access mode 1 or
malfunction code is present, see
codes" [ 4 38].
problems based on error
NOTICE
Make sure all connected units (heat exchanger unit +
indoor units) are recognised (setting [1‑5]).
To determine the additional refrigerant
amount
×Ø12.7)×0.12+(X
×Ø9.5)×0.059+(X
1
2
VRV IV compressor unit for indoor installation
b
a
2" [ 4 30]),
codes" [ 4 38].
2" [ 4 30]). If a
"19.1 Solving
×Ø6.4)×0.022]×A+B
3
RKXYQ5T8 + RKXYQ8T7Y1B
4P499900-1B – 2021.12
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