2
2
- 20
Design of 3-WAY FLOW LOGIC
2. System Design
2-2. Example of Tubing Size Selection for Extension and Additional Charge Amount
(3) Increasing the size of the refrigerant tubing
Increasing the tubing size of the suction and discharge tubes can reduce the loss of capacity caused by longer tub-
ing lengths. (Only the main suction and discharge tubes with the largest tube diameter (main tube LA and main
tubes after the distribution point that are the same size as LA) can be changed.) In this case, it is necessary to
recalculate the actual indoor unit capacities. Refer to the table below to increase the tubing size. However, total
tubing length must not exceed the maximum allowable tubing length.
Standard tube diameter
(suction and discharge tubes, mm)
Tube diameter after change
(suction and discharge tubes, mm)
Equivalent length
correction coefficient
φ
31.75
φ
38.1
φ
38.1
φ
41.28
0.6
0.7
Tubing equivalent length after size increase
= Standard tubing equivalent length
×
Equivalent length correction coefficient
• Correction coefficient for equivalent length when the size of the largest main
wide tube is increased
•
Sa
mple c
a
lc
u
l
a
tion for the
s
y
s
tem
b
elow
Con
s
t
a
nt-
s
peed
u
nit
s
Inverter
u
nit
O
u
tdoor
u
nit
s
10HP: EFL 100-
3
R410
10HP: EFL 100-
3
R410
8
HP: EFL
8
0-
3
R410
Exten
s
ion
indoor
u
nit
s
Exten
s
ion
o
u
tdoor
u
nit
s
Elev
a
tion difference
H = 4 m
Elev
a
tion difference
H = 5 m
Elev
a
tion difference
H = 5 m
Type 224
Type 2
8
0 Type 2
8
0
Type 2
8
0
Type 112
Type 112
Type 112
Type 56
Ld
Lc
L
b
LQ
LP
LN
LO
LA
LB
LG
LH
L7
LC
LD
LF
L4
L5
L6
LJ
L9
L10
L11
L
8
L1
L12
L1
3
L14
L15
LE2
LE1
L1
L2
L
3
L
a
Type 2
8
Type 2
8
Type
3
6
Type
8
0
Type
8
0
Type 45
Type 90
Type
8
0
Type 140
Type 90
Type 71
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