Design and Technical Manual

6. SYSTEM DESIGN
Limitation check
z
Diagram
Example
ft (m)
Limitation
ft (m)
Judge
Total pipe length Total
259
(80)
Less than 377 (115)
OK
Between outdoor unit and the farthest indoor unit a + b + c + m
115
(35)
Less than 230 (70)
OK
Between outdoor unit and branch boxes a + b + c + d + e
121
(37)
Less than 180 (55)
OK
Between branch box and indoor unit
Total f + g + h + i + j + k + l + m
138
(43)
Less than 197 (60)
OK
Each unit f, g, h, i, j, k, l, m
16 to 26
(5 to 8)
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)
138
(43)
121
(37)
Additional charge = (0.224 x 138) + (0.624 x 121) = 106.42 oz. = 6.65 lbs.
[Additional charge = (21 x 43) + (58 x 37) = 3049 g = 3.05 kg]
- (06 - 19) -
SYSTEM DESIGN SYSTEM DESIGN