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6. R
EFRIGERANT PIPING
Use R-410A to add refrigerant.
All field piping must be installed by a licensed refrigeration
technician and must comply with relevant local and
national regulations.
CAUTION TO BE TAKEN WHEN BRAZING
REFRIGERANT PIPING
Do not use flux when brazing copper-to-copper refrigerant
piping. (Particularly for the HFC refrigerant piping)
Therefore, use the phosphor copper brazing filler metal
(BCuP) which does not require flux.
Flux has extremely harmful influence on refrigerant piping
systems. For instance, if the chlorine based flux is used, it
will cause pipe corrosion or, in particular, if the flux
contains fluorine, it will damage the refrigerant oil.
Be sure to perform a nitrogen blow when brazing.
(Brazing without performing nitrogen replacement or
releasing nitrogen into the piping will create large
quantities of oxidized film on the inside of the pipes,
adversely affecting valves and compressors in the
refrigerating system and preventing normal operation.)
Installation tools:
NOTE
Make sure to use installation tools (gauge manifold
charge hose, etc.) that are exclusively used for R-410A
installations to withstand the pressure and to prevent
foreign materials (e.g. mineral oils such as SUNISO
and moisture) from mixing into the system.
(The screw specifications differ for R-410A and
R-407C.)
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.
6.1. Selection of piping material
1.
Foreign materials inside pipes (including oils for fabrication) must be
30 mg/10 m or less.
2.
Use the following material specification for refrigerant piping:
Size: determine the proper size referring to chapter
"6.3. Example of connection" on page
Construction material: phosphoric acid deoxidized seamless
copper for refrigerant.
Temper grade: use piping with temper grade in function of the
pipe diameter as listed in below table.
Pipe Ø
≤15.9
≥19.1
O = Annealed
1/2H = Half hard
The pipe thickness of the refrigerant piping should comply
with relevant local and national regulations. The minimal pipe
thickness for R-410A piping must be in accordance with the
table below.
Minimal thickness
Pipe Ø
t (mm)
6.4
0.80
9.5
0.80
12.7
0.80
15.9
0.99
19.1
0.80
Installation manual
4
7.
Temper grade of piping material
O
1/2H
Minimal thickness
Pipe Ø
t (mm)
22.2
0.80
28.6
0.99
34.9
1.21
41.3
1.43
3.
Make sure to use the particular branches of piping that have been
selected referring to chapter
page
7.
4.
In case the required pipe sizes (inch sizes) are not available, it is also
allowed to use other diameters (mm sizes), taken the following into
account:
select the pipe size nearest to the required size.
use the suitable adapters for the change-over from inch to
mm pipes (field supply).
6.2. Connecting the refrigerant piping
1
Installation of refrigerant piping is possible as front connection or
side connection (when taken out from the bottom) as shown in
the figure.
1
2
1
Left-side connection
2
Front connection
3
Right-side connection
[One outdoor unit installed: In case of U-5~16MX3]
Front connection:
Remove the stop valve cover to connect.
Side (bottom) connection:
Remove the knock holes on the bottom frame and route the piping
under the bottom frame.
(See figure 6)
A
Front connection
Remove the stop valve cover to connect.
B
Side (bottom) connection:
Remove the knock holes on the bottom frame and route the piping
under the bottom frame
1
Flange (or flare nut in case of models U-5MX3-type)
2
Gas side pipe (1)(2)(3) supplied with the unit. (In case of U-5MX3-
type, field supply.)
3
Oil-equalizing piping stop valve (except U-5MX3 and
U-8+10MX3). No piping work is needed
4
Flare nut
5
Brazing (Except U-5MX3)
6
Liquid side piping (field supply)
7
Knockout hole (use a hammer)
8
Gas side piping (field supply)
9
Oil-equalizing piping (field supply)
[When multiple outdoor units are installed: In case of
U-18~48MX3]
To connect the piping between outdoor units, an optional piping kit
(multi connection piping kit) is always required. When installing the
piping, follow the instructions in the installation manual that comes
with the kit.
Front connection:
Remove the stop valve cover to connect.
Side (bottom) connection:
Remove the knock holes on the bottom frame and route the piping
under the bottom frame.
(See figure 6)
"6.3. Example of connection" on
3
(See figure 6)
(See figure 6)
U-5~48MX3
Urban Multi air conditioner
4PW16235-1C
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