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4. PIPE SELECTION
4.1. Selecting the pipe material
CAUTION
Do not use existing pipes.
Use pipes that have clean external and internal sides without any contamination which
may cause trouble during use, such as sulfur, oxide, dust, cutting waste, oil, or water.
It is necessary to use seamless copper pipes.
Material: Phosphor deoxidized seamless copper pipes.
It is desirable that the amount of residual oil is less than 40 mg/10 m.
Do not use copper pipes that have a collapsed, deformed, or discolored portion
(especially on the interior surface).
Otherwise, the expansion valve or capillary tube may become blocked with
contaminants.
Improper pipe selection will degrade performance. As an air conditioner using R410A
incurs pressure higher than when using conventional refrigerant, it is necessary to
choose adequate materials.
Thicknesses of copper pipes used with R410A are as shown in the table.
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Never use copper pipes thinner than those indicated in the table even if they are
•
available on the market.
Thicknesses of Annealed Copper Pipes (R410A)
Pipe outside diameter [mm (in.)]
Thickness [mm]
6.35 (1/4)
0.80
9.52 (3/8)
0.80
12.70 (1/2)
0.80
15.88 (5/8)
1.00
19.05 (3/4)
1.20
4.2. Protection of pipes
Protect the pipes to prevent the entry of moisture and dust.
•
Especially, pay attention when passing the pipes through a hole or connecting the
•
end of a pipe to the outdoor unit.
Location
Working period
Protection method
Outdoor
1 month or more
Pinch pipes
Less than 1 month
Pinch or tape pipes
Indoor
-
Pinch or tape pipes
4.3. Refrigerant pipe size and allowable piping
length
CAUTION
Keep the piping length between the indoor unit and outdoor unit within the allowable
tolerance.
Capacity [BTU/h class]
45,000
54,000
Pipe diameter <Liquid/Gas> [mm (in.)]
9.52 (3/8) / 15.88 (5/8)
Max. piping length (L) [m]
50
Min. piping length (L) [m]
5
Max. height difference (H)
<Indoor unit to outdoor unit> [m]
30
View (Example)
H
L
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5. PIPE INSTALLATION-1
5.1. Opening a knock out hole
CAUTION
Be careful not to deform or scratch the panel while opening the knock out holes.
To protect the piping insulation after opening a knock out hole, remove any burrs from
the edge of the hole. It is recommended to apply rust prevention paint to the edge of
the hole.
Pipes can be connected from 4 directions, front, lateral side, rear side and bottom.
•
(Fig. A)
When connecting at the bottom, remove the service panel and piping cover on the
•
front of the outdoor unit, and open the knock out hole provided at the bottom corner
of the piping outlet.
It can be installed as shown on “Fig. B” cutting out the 2 slits as indicated on “Fig. C”.
•
(When cutting slits, use a steel saw.)
Fig. A
Service panel
Front
connection
Bottom
connection
(No. 1)
Lateral
connection
Rear
connection
Fig. B
Fig. C
Bottom
connection
(No. 2)
Slit
Slit
5.2. Brazing
CAUTION
If air or another type of refrigerant enters the refrigeration cycle, the internal pressure in
the refrigeration cycle will become abnormally high and prevent the unit from exerting
its full performance.
Apply nitrogen gas while brazing the pipes. If a pipe is brazed without applying nitro-
gen gas, an oxidation film will be created.
This can degrade performance or damage the parts
in the unit (such as the compressor or valves).
Nitrogen gas pressure: 0.02 MPa
(= pressure felt sufficiently on the back of the hand)
Pressure regulating valve
Cap
Brazing area
Nitrogen gas
For brazing material, use phosphor copper that does not require flux. Do not use flux to
braze pipes. If the flux is the chlorine type, it will cause the pipes to corrode.
Furthermore, if the flux contains fluoride, it will adversely affect the refrigerant pipe
system such as by degrading the refrigerant.
If fluoride is contained, quality of refrigerant deteriorates and affects the refrigerant
piping system.
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