Fujitsu AB* A12GATH, Design & Technical Manual

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„ z
Selection of pipe size
*a b b1 c d e1 e2 f1 f2 f3
Liquid pipe 12.70 12.70 9.52 9.52 9.52 6.35 6.35 6.35 6.35 6.35
Gas pipe 22.22 22.22 15.88 15.88 15.88 12.70 12.70 9.52 9.52 9.52
Length (m)
Example
75 5 10 5 5 10 5 5 5 5
„ 
Pipe size "a" selection : The length that between outdoor unit and first separation tube or
header. (Condition 2)
a = 75 > 70 m
Therefore Liquid pipe must be size up from 9.52 mm to 12.70 mm. (Refer 2-3. PIPE SIZE)
„ z
Limitation check
Diagram
Example
(m)
Limitation
(m)
Judge
Total pipe length Total 155 400m or less OK
Between outdoor unit and farthest indoor unit a+b+c+f3 110 120m or less OK
Between the first separation tube and the farthest indoor unit b+c+f3 30 90m or less OK
Between outdoor unit and the nearest indoor unit a+b1 90 5m or more OK
Between outdoor unit and the first seperation tube a 75 3m or more OK
„ z
Calculation of additional charge refrigerant
1. Calculation of additional amount for pipe length
Liquid pipe size 12.70 9.52 6.35
Additional refrigerant
(kg/m)
0.114 0.058 0.021
Liquid pipe length (m) 80 20 30
A = (0.114 x 80) + (0.058 x 20) + (0.021 x 30) = 10.91 (kg)
2. Factory charged amount
Model
Factory charged
amount (kg)
Outdoor unit AJ

090 7.5
B = 7.5 (kg)
3. Total refrigerant amount check
C = A + B = 10.91 + 7.5 = 18.41 (kg) < 20.0 (kg) → OK
Check pipe length and height difference between units by comparing with items shown in "2-2.PIPING
LIMITATION".
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