250B8W1B
Split system air conditioner
4PW25544-1A
Installation manual
6
7.7.
Connecting the refrigerant piping
1
Installation of refrigerant branching kit.
For installation, refer to the installation manual delivered with the
kit. Follow the conditions listed below:
■
Mount the refnet joint so that it branches either horizontally
(see view
A
) or vertically.
2
Installation of refrigerant piping is possible as front connection or
side connection (when taken out from the bottom) as shown in
the figure below.
■
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.
Precautions when knocking out knockout holes
■
Be sure to avoid damaging the casing.
■
After knocking out the holes, we recommend you paint the
edges and areas around the edges using the repair paint to
prevent rusting.
■
When passing electrical wiring through the knock holes, wrap
the wiring with protective tape to prevent damage.
3
Make sure to perform the piping installation within the range of
the maximum allowable pipe length, allowable level difference
and allowable length after branching as indicated in
"7.4. Allowable pipe length and height difference" on page 5
4
For installation of the refrigerant branching kit (Refnet), refer to
the installation manual delivered with the kit.
5
Pipe connection
■
Only use the flare nuts included with the unit.
Using different flare nuts may cause the refrigerant to leak.
■
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.)
FLARE SHAPE and FLARENUT TIGHTENING TORQUE
Precautions when connecting pipes
■
See the following table for flare part machining dimensions.
■
When connecting the flare nuts, apply refrigerant oil to the inside
and outside of the flares and turn them three or four times at first.
(Use ester oil or ether oil.)
■
When loosening a flare nut, always use two wrenches in
combination.
When connecting the piping, always use a spanner and torque
wrench in combination to tighten the flare nut.
■
See the following table for tightening torque.
(Applying too much torque may cause the flares to crack.)
■
After all the piping has been connected, use nitrogen to perform
a gas leak check.
1
Horizontal surface
1
Left-side connection
2
Front connection
3
Right-side connection
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
2
Gas side pipe (1)(2)(3) supplied with the unit.
3
Flare nut
4
Brazing
5
Liquid side piping (field supply)
6
Knockout hole (use a hammer)
7
Gas side piping (field supply)
1
2
3
NOTE
The pressure regulator for the nitrogen released when
doing the brazing should be set to 0.02 MPa or less.
Do not use anti-oxidants when brazing the pipe joints.
Residue can clog pipes and break equipment.
Pipe size
Tightening
Torque (N•m)
A (mm)
Flare shape
Ø9.5
32.7~39.9
12.8~13.2
Ø12.7
49.5~60.3
16.2~16.6
Ø15.9
61.8~75.4
19.3~19.7
NOTE
You must use a torque wrench but if you are unable to
install the unit with a torque wrench, you may follow the
installation method mentioned below.
After the work is finished, make sure to check that
there is no gas leak.
When you keep on tightening the flare nut with a
spanner, there is a point where the tightening torque
suddenly increases. From that position, further tighten
the flare nut within the angle shown below:
1
Refrigerant piping
2
Location to be brazed
3
Nitrogen
4
Taping
5
Manual valve
6
Regulator
1
Piping union
2
Spanner
3
Flare nut
4
Torque wrench
3
4
1
2
R=0.4~0.8
45
±
2
90
±
2
A
Pipe size
Further
tightening angle
Recommended
arm length of tool
Ø9.5 (3/8")
60~90°
200 mm
Ø12.7 (1/2")
30~60°
250 mm
Ø15.9 (5/8")
30~60°
300 mm
