Design and Technical Manual

6. SYSTEM DESIGN
Limitation check
z
Diagram
Example
ft (m)
Limitation
ft (m)
Judge
Total pipe length Total
234
(72)
Less than 377 (115)
OK
Between outdoor unit and the farthest indoor unit a + c + k
121
(37)
Less than 230 (70)
OK
Between outdoor unit and branch boxes a + c + d
138
(42)
Less than 180 (55)
OK
Between branch box and indoor unit
Total f + g + h + i + j + k
96
(30)
Less than 197 (60)
OK
Each unit f, g, h, i, j, k
16
(5)
Between 10 to 49
(3 to 15)
OK
Between outdoor unit and the rst separation tube a
23
(7)
Greater than 16 (5)
OK
Calculation of additional charge refrigerant
z
Liquid pipe size
in. (mm)
1/4
(6.35)
3/8
(9.52)
Additional refrigerant
oz./ft. (g/m)
0.224
(21)
0.624
(58)
Liquid pipe length
ft (m)
96
(30)
138
(42)
Additional charge = (0.224 x 96) + (0.624 x 138) = 107.62 oz. = 6.73 lbs
[Additional charge = (21 x 30) + (58 x 42) = 3066 g = 3.07 kg]
- (06 - 21) -
SYSTEM DESIGN SYSTEM DESIGN