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Maximum allowable length after branch
The pipe length from the first refrigerant branch kit to the indoor unit
≤130 ft. (40 m)
Example 1.1: unit 8: b+c+d+e+f+g+p≤130 ft. (40 m)
Example 1.2: unit 6: b+h≤130 ft. (40 m), unit 8: i+k≤130 ft. (40 m)
Example 1.3: unit 8: ≤130 ft. (40 m)
However, extension is possible if all below conditions are met. In this
case limitation can be extended up to 295 ft. (90 m ).
1
a
b
c
d
2
A
B
C
D
h
i
j
k
3
1
2
3
1 Outdoor units
2 REFNET joints (A – G)
3 Indoor unit (1 – 8)
a The piping length between all indoor to the nearest branch kit is
≤130 ft. (40 m)
Example: h, I, j ... p≤130 ft. (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 farthest indoor unit is
over 130 ft. (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:
f3/8 → f1/2; f1/2 → f5/8; f5/8 → f3/4; f3/4 → f7/8; f7/8 → f1
f1-1/8 → f1-1/4
; f1-3/8 → f1-1/2
(3)
Example: unit 8: b+c+d+e+f+g+p≤295 ft. (90 m) and
b+c+d+e+f+g>130 ft. (40 m); increase the pipe size of b, c, d, e, f, g.
(3) If available on the site. Otherwise it cannot be increased.
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≤1640 ft. (500 m).
d The piping length difference between the nearest indoor from the
first branch to the outdoor unit and farthest indoor to the outdoor
unit is ≤130 ft. (40 m).
Example: The farthest indoor unit 8. The nearest indoor unit 1 →
(a+b+c+d+e+f+g+p)–(a+h) ≤130 ft. (40 m).
13
e
f
g
E
F
G
p
H1
l
m
n
4
5
6
7
8
H2
(3)
;
(3)
;
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