11
English
9.
REFRIGERANT PIPING
CAUTION
After completing installation, be sure to open the valves.
(See
9-9 Additional refrigerant charge
for details) (Operating the
unit with the valves shut will break the compressor.)
Use R410A to add refrigerant. (The R410A refrigerant cylinder has
a pink stripe painted around it.)
All field piping must be installed by a licensed refrigeration techni-
cian 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-2: JIS Z 3264/B-
Cu93P-710, 795: ISO 3677) which does not require flux.
(Flux has an extremely negative effect on refrigerant piping sys-
tems. 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.)
NOTE
•
Installation tools:
Gauge manifold, charge hose, etc.
Make sure to use installation tools that are exclusively used for
R410A installations to withstand the pressure and to prevent for-
eign materials (e.g. mineral oils such as SUNISO and moisture)
from mixing into the system.
(The screw specifications differ for R410A and R407C.)
Vacuum pump
1.
Use a 2-stage vacuum pump with a non-return valve.
2.
Make sure the pump oil does not flow oppositely into the system
while the pump is not working.
3.
Use a vacuum pump which can evacuate to –14.6 psi.
9-1 Selection of piping material
1.
Foreign materials inside pipes (including oils for fabrication) must be
9 mg/10 ft or less.
2.
Use the following material specification for refrigerant piping:
•
Construction material: Phosphoric acid deoxidized seamless
copper for refrigerant.
•
Size: Determine the proper size referring to chapter “Example of
connection”.
•
The wall thickness of the refrigerant piping should comply with
relevant local and national regulations. For R410A the design
pressure is 450 psi.
3.
Make sure to use the particular branches of piping that have been
selected referring to chapter “Example of connection”.
4.
Refer to chapter “Stop valve operation procedure” in 9-10 about the
stop valve operation procedure.
5.
Make sure to perform the piping installation within the range of the
maximum allowable pipe length, allowable level difference and allow-
able length after branching as indicated in chapter “Example of con-
nection”
6.
For installation of the refrigerant branching kit, refer to the installation
manual delivered with the kit.
And follow the conditions listed below.
•
Mount the REFNET joint so that it branches either horizontally or
vertically.
•
Mount the REFNET header so that it branches horizontally.
(Refer to figure 22)
1.
Horizontal connections
2.
Up to ± 30° or vertically
3.
Horizontal connections
7.
To connect the piping between outside 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.
Restriction for the installation of the outside unit multi connection
piping kit
• Install the joint horizontally within a lean of ±15° with caution name-
plate on top. Refer to figure 23 (Fig. A)
Do not connect it vertically. Refer to figure 23 (Fig. B)
• Reserve the straight part of 19-11/16 in. or more to the branch pipe
and do not bend the local pipe in that area.Straight part of 19-11/16
in. or more can be reserved if a local pipe (straight pipe) of 4-3/4 in.
or more is connected to the joint. Refer to figure 23 (Fig. C)
• Incorrect installation may cause breakage of outside unit.
(Refer to figure 23)
1.
Caution nameplate
2.
Horizontal line
3.
Ground
4.
Straight part of 19-11/16 in. or more
5.
Local pipe
(4-3/4 in. length or more)
Precautions when selecting branch piping.
• If the overall equivalent length of piping between the outside units
and indoor units is 262.5 ft or more, be sure to enlarge the main pipe
in the liquid-side branch piping.
Depending on the length of the refrigerant piping, the cooling/heat-
ing capacity may drop, but even in such cases it is ok to enlarge the
main pipe.
(Refer to figure 21)
1.
Outside unit
2.
Main pipe
3.
Enlarge
4.
The first refrigerant branching kit.
5.
Indoor unit
[Liquid side]
RWEYQ72/84PTJU type:
............................................ φ
3/8”
→
φ
1/2”
RWEYQ144PTJU type:
............................................... φ
1/2”
→
φ
5/8”
RWEYQ168/216PTJU type:
....................................... φ
5/8”
→
φ
3/4”
RWEYQ252PTJU type:
............................................... φ
3/4”
→
φ
7/8”
9-2 Protection against contamination when install-
ing pipes
•
Take measures to prevent foreign materials like moisture and
contamination from mixing into the system.
•
Great caution is needed when passing copper tubes through
walls.
9-3 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 com-
pressors in the refrigerating system and preventing normal oper-
ation.)
•
Do not use a flux when brazing the refrigerant pipe joints.
Use phosphor copper brazing (B-Cu93P-710/795: ISO 3677)
which does not require flux.
(Flux has an extremely negative effect on refrigerant piping sys-
tems. For instance, if chlorine based flux is used, it will cause pipe
corrosion. If the flux contains fluorine, it will damage the refriger-
ant oil.)
DANGER
•
Use of oxygen could cause an explosion resulting in severe injury
or death. Only use nitrogen gas.
•
Refrigerant gas may produce toxic gas if it comes in contact with fire
such as from a fan heater, stove or cooking device. Exposure to this
gas could cause severe injury or death.
NOTE
•
The pressure regulator for the nitrogen released when doing the
brazing should be set to 2.9 psi or less.
(Refer to figure 18)
1.
Refrigerant piping
2.
Location to be brazed
3.
Nitrogen
4.
Taping
5.
Manual valve
6.
Regulator
Place
Installation period
Protection method
Outdoor
More than a month
Pinch the pipe
Less than a month
Pinch or tape the pipe
Indoor
Regardless of the period
