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5 Preparation
Installer and user reference guide
15
RXYTQ8~16T7YF
VRV IV system air conditioner
4P388989-1B – 2016.02
Maximum allowable height difference
H1
≤50 m (40 m)
(if outdoor is located below indoor units)
Conditional extension up till 90 m is possible without
additional option kit:
▪ In case the outdoor location is higher than indoor:
extension is possible up till 90 m and following
2 conditions must be fulfilled:
▪ Liquid piping size up (see table "Size up" in
"E: Piping
between refrigerant branch kit and indoor unit" on
page 13
).
▪ Dedicated setting on outdoor unit is required (see [2‑49]
in
"7.2.8 Mode 2: Field settings" on page 34
).
▪ In case the outdoor location is lower than indoor:
extension is possible up till 90 m and following
6 conditions must be fulfilled:
▪ 40~60 m: minimum connection ratio connected: 80%.
▪ 60~65 m: minimum connection ratio connected: 90%.
▪ 65~80 m: minimum connection ratio connected: 100%.
▪ 80~90 m: minimum connection ratio connected: 110%.
▪ Liquid piping size up (see table "Size up" in
"E: Piping
between refrigerant branch kit and indoor unit" on
page 13
).
▪ Dedicated setting on outdoor unit is required (see [2‑35]
in
"7.2.8 Mode 2: Field settings" on page 34
).
H2
≤30 m
H3
≤5 m
Maximum allowable length after branch
The pipe length from the first refrigerant branch kit to the indoor unit
≤40 m.
Example 1.1: unit 8: b+c+d+e+f+g+p≤40 m
Example 1.2: unit 6: b+h≤40 m, unit 8: i+k≤40 m
Example 1.3: unit 8: i≤40 m
However, extension is possible if all below conditions are met. In this
case limitation can be extended up to 90 m.
a
A
h
i
j
k
l
m
n
B
C
D
E
F
G
p
b
c
d
e
f
1
2
3
4
5
6
7
8
g
H1
H2
1
2
3
1
Outdoor units
2
Refnet joints (A~G)
3
Indoor unit (1~8)
Conditions:
a
The piping length between all indoor to the nearest branch kit is
≤40 m.
Example: h, i, j … p≤40 m
b
It is necessary to increase the pipe size of the gas and liquid
piping if the pipe length between the first and the final branch kit
is over 40 m.
If the increased pipe size is larger than the pipe size of the main
pipe, then the pipe size of the main pipe has to be increased as
well.
Increase the pipe size as follows:
9.5 → 12.7; 12.7 → 15.9; 15.9 → 19.1; 19.1 → 22.2; 22.2 →
25.4
(a)
; 28.6 → 31.8
(a)
; 34.9 → 38.1
(a)
(a)
If the size-up size is NOT available, you must use the
standard size. Sizes bigger than the size-up size are NOT
allowed. But even if you use the standard size, you can
increase the maximum allowable length after the first branch if
all other conditions are met.
Example: unit 8: b+c+d+e+f+g+p≤90 m and b+c+d+e+f+g
>40 m; increase the pipe size of b, c, d, e, f, g.
c
When the piping size is increased (step b), the piping length
has to be counted as double (except for the main pipe and the
pipes that are not increased in pipe size).
The total piping length has to be within limitations (see table
above).
Example: a+b×2+c×2+d×2+e×2+f×2+g×2+h+i+j+k+l+m+n
+p≤1000 m (500 m).
d
The piping length difference between the nearest indoor from
first branch to the outdoor unit and farthest indoor to the
outdoor unit is ≤40 m.
Example: The farthest indoor unit 8. The nearest indoor unit 1
→ (a+b+c+d+e+f+g+p)–(a+h)≤40 m.
5.3.6
Multiple outdoor units: Possible layouts
▪ The piping between the outdoor units must be routed level or
slightly upward to avoid the risk of oil retention into the piping.
Pattern 1
Pattern 2
a
b
b
a
b
a
a
b
a
b
b
a
a
To indoor unit
b
Piping between outdoor units
X
Not allowed
O
Allowed
▪ To avoid the risk of oil retention to the outmost outdoor unit,
always connect the stop valve and the piping between outdoor
units as shown in the 4 correct possibilities of the figure below.
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