Specifications

Installation and operation manual
16
RXYQQ8~20T7Y1B
VRV IV System Air Conditioner
4P345099-1 – 2013.04
1 To indoor units
2 Outdoor unit multi connecting piping kit (first branch)
3 Outdoor unit multi connecting piping kit (second branch)
10. Precautions on refrigerant piping
 Do not allow anything other than the designated refrigerant to
get mixed into the refrigerant cycle, such as air, nitrogen, etc. If
any refrigerant gas leaks while working on the unit, ventilate the
room thoroughly right away.
 When the design pressure for the existing field piping (gas and
liquid piping) is at least 33 bar (3.3 MPa), then it is possible to
use the existing piping (please read "9. Refrigerant pipe size and
allowable pipe length" on page 11). Check also if the existing
piping (including branch piping) is compatible with the unit in
terms of materials and thickness and if the pipes and branch
piping are not corroded.
If the existing field piping does not comply with the conditions
above, replace the existing field piping with field piping which
meets the specified conditions.
 Check if there was no compressor malfunction or similar issues
that could contribute to piping problems in the past. If there
where such problems, check that the appropriate repairs where
made, and if not, implement such repairs.
 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).
Example: passing piping out through the front.
 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.
1 Refrigerant piping
2 Part to be brazed
3 Taping
4 Hands valve
5 Pressure-reducing valve
6 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.
NOTICE
There are restrictions on the refrigerant pipe connection
order between outdoor units during installation in case of a
multiple outdoor unit system. Install according to following
restrictions. The capacities of outdoor units A, B and C
must fulfill the following restriction conditions: A≥B≥C.
Installation period Protection method
More than a month Pinch the pipe
Less than a month
Pinch or tape the pipe
Regardless of the period
ABC
1
23
NOTICE
After all the piping has been connected, make sure there is
no gas leak. Use nitrogen to perform a gas leak detection.
1
1 Close the areas marked with " ".
(When the piping is routed from the
front panel.)
12 345
6
6