Specifications
SiUS34-907
Appendix
4. Example of Connection
Example of connection
(Connection of 8 indoor units
Heat Pump system)
Branch with REFNET joint
Branch with REFNET joint and REFNET header
Branch with REFNET header
ab c d e f
g
hi j kl mn
1234567
8
H2
H1
p
Outdoor unit
REFNET joint (A-G)
Indoor units (1-8)
H1
H2
a
a
i
i
b
cde f
g
h
123456
Outdoor unit
REFNET joint (A • B)
Indoor units (1-8)
REFNET header
k
j
78
H1
H2
Outdoor unit
REFNET header
Indoor units (1-8)
cde
f
g
h
b
1234567
8
Maximum
allowable
length
Between outdoor and
indoor units
Between outdoor and indoor units
Between indoor and indoor units
Actual pipe length
Actual pipe length
Difference in height
Difference in height
Equivalent length
Total extension length
Allowable
height
length
Allowable length after the branch
How to calculate the additional refrigerant to be charged
Additional refrigerant to be charged R (lb.)
R should be rounded off in units of 0.1lb.
ABCDEFG
A
B
〈Caution on selecting connection pipes〉
Pipe size selection
Caution)
In brazing connection in the size increase area in the piping, use a
different-diameter joint for connection. (The different-diameter joint
should be arranged in the local field.)
The connection area is located near the outdoor unit (usually after
the first bending outside the unit).
[Gas side]
Outdoor unit
The first refrigerant
branching kit
Enlarge
Indoor unit
Main pipe
Pipe length between outdoor and indoor units ≤ 492ft.
Example unit 8: a + b + c + d + e + f + g + p ≤ 492ft.
Example unit 8: a + i ≤ 492ft.
Example unit 6: a + b + h ≤ 393ft., unit 8: a + i + k ≤ 492ft.
Equivalent pipe length between outdoor and indoor units ≤ 580ft. (assume equivalent pipe length of REFNET joint to be 1.6ft., that of REFNET header to be 3.2ft., calculation purposes)
Total piping length from outdoor unit to all indoor units ≥33ft., ≤ 1000ft.
Difference in height between outdoor and indoor units (H1) ≤ 164ft. (Max 130ft. if the outdoor unit is below)
Difference in height between adjacent indoor units (H2) ≤ 49ft.
Example unit 8: b + c + d + e + f + g + p ≤ 130ft.
Pipe length from first refrigerant branch kit (either REFNET joint or REFNET header ) to indoor unit ≤ 130ft.
Example unit 8: i ≤ 130ft.
Example unit 6: b + h ≤ 130ft., unit 8:i + k ≤ 130ft.
Refrigerant branch kit selection
Use REFNET joint from the following table.
RXYMQ36,48 type
KHRP26M22T
Outdoor unit capacity type
Refrigerant branch kit name
How to select the REFNET header
• Choose from the following table below the REFNET header according
to the number of units on the system.
RXYMQ36,48 type
KHRP26M22H (Max. 4 branch)
KHRP26M33H (Max. 8 branch)
Outdoor unit capacity type
•
When the equivalent piping length between the outdoor unit and the
indoor unit is 295ft. or more, make sure to use a thicker pipe as the
main pipe on the gas side.
When the air conditioning ability is reduced due to the refrigerant
piping distance, a thicker pipe may be used also as the main pipe.
(Unit: in.)
φ5/8” (15.9mm)
φ3/4”
(19.1mm)
Outdoor unit connection pipe size Connection pipe size
Gas pipe
Outdoor unit
capacity type
Piping size (outer diameter)
φ 3/8 (9.5mm)
Liquid pipe
RXYMQ36,48
type
Piping between outdoor unit and refrigerant branch kit
•
Match to the size of the connection piping on the outdoor unit.
(Unit: in.)
(Unit: in.)
Piping between refrigerant branch kits
•
Use the pipe size from the following table.
Piping size (outer diameter)
φ5/8” (15.9mm)
φ3/8” (9.5mm)
Gas pipe
Liquid pipe
24 · 30 · 36 ·
48 type
φ1/2”
(12.7mm)
φ1/4”
(6.4mm)
φ5/8”
(15.9mm)
φ3/8”
(9.4mm)
07 · 09 ·12 ·
18 type
Piping size
(outer diameter)
Indoor unit
capacity type
Gas pipe
Liquid pipe
Between refrigerant branch kit and indoor unit
•
Pipe size for direct connection to indoor unit must be the
same as the connection size of indoor unit.
Indoor unit connection pipe size
R=
+
Total length (ft.)
of liquid piping
size at φ3/8”
⎛
⎜
⎝
⎞
⎟
⎠
×0.036
Total length (ft.)
of liquid piping
size at φ1/4”
⎛
⎜
⎝
⎞
⎟
⎠
×0.015
Example for refrigerant branch using REFNET joint and REFNET header
a: × 100ft.
b: × 30ft.
c: 03/8”
3/8”
3/8”
× 30ft.
d: 3/8” × 40ft.
e: 1/4”
1/4”
× 30ft.
f : × 30ft.
g: 11/4” × 30ft.
h: 11/4” × 60ft.
i : 3/8” × 30ft.
j : 11/4” × 30ft.
k: 11/4” × 30ft.
The piping
lengths are as
at right
R= 220 0.036 + 210 0.015 = 11.07
a+b+c+d+i e+f+g+h+j+k
11.1
Refrigerant branch kits can only be
used with R-410A.
φ5/8” (15.9mm) → φ3/4” (19.1mm)
Refrigerant branch kit name
* When the size is larger