10T8Y1B
VRV-W IV System Air Conditioner
4P399208-1 – 2015.01
Installation and operation manual
15
10. Precautions on refrigerant piping
Do not allow anything other than the designated refrigerant to
get mixed into the refrigerant cycle. If any refrigerant gas leaks
while working on the unit, ventilate the room thoroughly right
away.
Use R410A only when adding refrigerant
Installation tools:
Make sure to use installation tools (gauge manifold, charge
hose, etc.) that are exclusively used for R410A installations to
withstand the pressure and to prevent foreign materials (e.g.,
mineral oils and moisture) from mixing into the system.
Vacuum pump:
- Use a 2-stage vacuum pump with a non-return valve.
- Make sure the pump oil does not flow oppositely into the
system while the pump is not working.
- Use a vacuum pump which can evacuate to –100.7 kPa
(5 Torr, –755 mm Hg).
Protection against contamination when installing pipes
Take measures to prevent foreign materials like moisture and
contamination from mixing into the system.
Block all gaps in the holes for passing out piping and wiring using
sealing material (field supply) (the capacity of the unit will drop and
small animals may enter the machine).
Use clean pipes only.
Hold the pipe end downwards when removing burrs.
Cover the pipe end when inserting it through a wall so that no
dust or dirt enters the pipe.
10.1. Caution for brazing
Make sure to blow through with nitrogen when brazing. Blowing
through with nitrogen prevents the creation of large quantities of
oxidized film on the inside of the piping. An oxidized film
adversely affects valves and compressors in the refrigerating
system and prevents proper operation.
The nitrogen pressure should be set to 0.02 MPa (i.e., just
enough so it can be felt on the skin) with a pressure-reducing
valve.
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Refrigerant piping
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Part to be brazed
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Taping
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Hands valve
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Pressure-reducing valve
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Nitrogen
Do not use anti-oxidants when brazing the pipe joints. Residue can
clog pipes and break equipment:
Do not use flux when brazing copper-to-copper refrigerant
piping. Use phosphor copper brazing filler alloy (BCuP) which
does not require flux.
Flux has an extremely harmful influence on refrigerant piping
systems. For instance, if chlorine based flux is used, it will cause
pipe corrosion or, in particular, if the flux contains fluorine, it will
deteriorate the refrigerant oil.
10.2. Connecting the refrigerant piping
10.2.1 Connecting refrigerant piping to the outdoor unit
Connection from the stop valves to the field piping can be done by
using accessory pipes supplied as accessory.
The connections to the branch kits are the responsibility of the
installer (field piping).
Installation period
Protection method
More than a month
Pinch the pipe
Less than a month
Pinch or tape the pipe
Regardless of the period
NOTICE
After all the piping has been connected, make sure there is
no gas leak. Use nitrogen to perform a gas leak detection.
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NOTICE
Installation shall be done by an installer, the choice of
materials and installation shall comply with the applicable
legislation. In Europe, EN 378 is the applicable standard
that shall be used.
Ensure that the field piping and connections are not
subjected to stress.
Only use flare nuts included with the unit. Using different
flare nuts may cause the refrigerant to leak.
INFORMATION
All local inter unit piping are field supplied except the
accessory pipes.
NOTICE
Precautions when connecting field piping. Add brazing
material as shown in the figure.
NOTICE
Be sure to use the supplied accessory pipes when
carrying out piping work in the field.
Be sure that the field installed piping does not touch
other pipes, the bottom panel or side panel. Especially
for the bottom and side connection, be sure to protect
the piping with suitable insulation, to prevent it from
coming into contact with the casing.
NOTICE
Make sure that the on-site piping does not come in contact
with other piping, the bottom frame or side panels of the
unit.
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