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Type B) If connecting 2 or more indoor units downstream of the RB unit
Select the connection pipe from Table 1, based on the
total capacity of indoor units connected downstream.
Suction gas pipe
Liquid pipe
Discharge gas pipe
• Select the connection pipe from Table 2, based
on the total capacity of indoor units connected
downstream.
• For piping from branch kit to indoor unit, refer to
the installation manual for the outdoor unit.
Indoor unit
(2) If the size of the selected pipe is different from Table 4, use reducers (accessories)
to make the diameters match.
Connection pipe
Reducer
Table 1) Indoor unit total capacity and RB unit upstream side connection pipe sizes
Total capacity of
Suction gas pipe
indoor unit [Btu/h]
[in (mm)]
ø5/8 (15.88)
4,000 ≤ x < 36,000
+Reducer
ø3/4 (19.05)
36,000 ≤ x < 48,000
+Reducer
ø7/8 (22.22)
48,000 ≤ x < 72,000
+Reducer
ø7/8 (22.22)
72,000 ≤ x < 96,500
+Reducer
96,500 ≤ x < 153,000
ø1-1/8 (28.58)
153,000 ≤ x < 161,000
ø1-1/8 (28.58)
161,000 ≤ x < 193,000
ø1-1/8 (28.58)
193,000 ≤ x < 270,000
ø1-3/8 (34.92)
270,000 ≤ x < 324,000
ø1-3/8 (34.92)
• If there is a plan or possibility of adding indoor units in the future, select a pipe
diameter that can support the increased connected capacity.
Table 2) Indoor unit total capacity and RB unit downstream side connection
pipe sizes
Total capacity of
indoor unit (Btu/h)
8,000 to 27,000
• To make sure that the piping diameters match, cut the RB unit outlet branch fi rst
before connecting it to the mating pipe.
Table 3) Indoor unit capacity and connection pipe sizes
Indoor unit capacity (Btu/h)
4,000 7,500 9,500
12,000 14,000
18,000 24,000
ø5/8 (15.88) *1
To connect an indoor unit with a capacity exceeding
30,000 34,000 36,000
27,000 Btu/h, an optionally available separation tube
48,000 60,000 72,000
kit must be used to merge 2 or 4 outlet pipe branches.
96,000
For more detail, refer to the separation tube kit instal-
lation manual.
*1) To make sure that the piping diameters match, cut the RB unit outlet branch fi rst
before connecting it to the mating pipe.
RB unit
Liquid pipe
Gas pipe
Indoor unit
RB unit
Upstream of RB unit
Discharge gas
Liquid pipe
pipe [in (mm)]
[in (mm)]
ø1/2 (12.7)
ø3/8 (9.52)
+Reducer
+Reducer
ø1/2 (12.7)
ø3/8 (9.52)
+Reducer
+Reducer
ø5/8 (15.88)
ø1/2 (12.7)
+Reducer
+Reducer
ø3/4 (19.05)
ø1/2 (12.7)
+Reducer
+Reducer
ø3/4 (19.05)
ø1/2 (12.7)
+Reducer
+Reducer
ø3/4 (19.05)
ø5/8 (15.88)
+Reducer
ø7/8 (22.22)
ø5/8 (15.88)
ø5/8 (15.88)
ø1-1/8 (28.58)
+ Reducer
ø1-1/8 (28.58)
ø3/4 (19.05)
Downstream of RB unit
Outside diameter [in (mm)]
Gas pipe
Liquid pipe
ø5/8 (15.88)
ø3/8 (9.52)
Downstream of RB unit
Outside diameter [in (mm)]
Gas pipe
Liquid pipe
ø1/2 (12.70)
ø1/4 (6.35)
ø3/8 (9.52) *1
Table 4) RB unit pipe size
Outdoor unit side
Outside diameter [in (mm)]
Suction gas pipe Discharge gas pipe
ø1-3/8 (34.92)
ø1-1/8 (28.58)
(3) Indoor unit model codes and model selection capacity
Model code
04
07
Indoor unit capacity
4,000
7,500
[Btu/h]
Model code
30
34
Indoor unit capacity
30,000 34,000 36,000 48,000 60,000 72,000 96,000
[Btu/h]
■ Cut the indoor side pipe of the RB unit with a pipe cutter.
Liquid pipe : ø1/4(6.35) → ø3/8(9.52)
Gas pipe
: ø1/2(12.7) → ø5/8(15.88)
Connection area
Cutting point (Center
of connection area)
NOTE: Insert the connection pipe fi rmly until it touches the RB unit pipe.
• Use a pipe cutter to cut a pipe. When removing burrs after pipe cutting, make sure
that loose particles do not get into the pipe.
6.2. Selecting the pipe material
Copper pipes
It is necessary to use seamless copper pipes and it is desirable that the amount of
residual oil is less than 0.04 oz/100 ft (40 mg/10 m). Do not use copper pipes having a
collapsed, deformed or discolored portion (especially on the interior surface). Other-
wise, the expansion valve or capillary tube may become blocked with contaminants.
As an air conditioner using R410A incurs pressure higher than when using conventional
refrigerant (R22), it is necessary to choose adequate materials.
Thicknesses of copper pipes used with R410A are as shown in the table. Never use
copper pipes thinner than that in the table even when it is available on the market.
Thicknesses of Annealed Copper Pipes (R410A)
Pipe outside diam-
Thickness
eter [in (mm)]
[in (mm)] *1
ø1/4 (6.35)
0.032 (0.80)
ø3/8 (9.52)
0.032 (0.80)
ø1/2 (12.7)
0.032 (0.80)
ø5/8 (15.88)
0.039 (1.00)
ø3/4 (19.05)
0.047 (1.20)
ø7/8 (22.22)
0.039 (1.00)
ø1-1/8 (28.58)
0.039 (1.00)
ø1-3/8 (34.92)
0.047 (1.20)
*1 Endurance pressure of the pipes :609 psi(4.2 MPa)
Indoor unit side
Outside diameter [in (mm)]
Liquid pipe
Gas pipe
Liquid pipe
ø3/4 (19.05)
ø1/2 (12.7)
ø1/4 (6.35)
09
12
14
18
9,500
12,000 14,000 18,000 24,000
36
48
60
72
Connect
Connection pipe
CAUTION
Material
COPPER JIS H3300
C1220T-O or equivalent
(Allowable tensile
2
stress ≥ 33 (N/mm
))
COPPER JIS H3300
C1220T-H or equivalent
(Allowable tensile
2
stress ≥ 61 (N/mm
))
24
96
En-6
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