Design and Technical Manual

6. SYSTEM DESIGN
Limitation check
z
Diagram
Example
ft (m)
Limitation
ft (m)
Judge
Total pipe length Total
275
(84)
Less than 377 (115)
OK
Between outdoor unit and the farthest indoor unit c + h
197
(60)
Less than 230 (70)
OK
Between outdoor unit and branch box c
148
(45)
Less than 180 (55)
OK
Between branch box and indoor unit
Total f + g + h
127
(39)
Less than 197 (60)
OK
Each unit f, g, h
39 to 49
(12 to 15)
Between 10 to 49
(3 to 15)
OK
Between outdoor unit and branch box
(When there is no separation tube)
c
148
(45)
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)
127
(39)
148
(45)
Additional charge = (0.224 x 127) + (0.624 x 148) = 120.80 oz. = 7.55 lbs
[Additional charge = (21 x 39) + (58 x 45) = 3429 g = 3.43 kg]
- (06 - 23) -
SYSTEM DESIGN SYSTEM DESIGN