8
Allowable length and altitude difference of refrigerant pipe
Maximum
Piping(L)
Indoor Unit to Indoor Unit Drop Height(H)
Equivalent Length
Actual Length
or L1+L3+L5+f(The second connect method)
or L3+L5+f(The second connect method)
L1+L2+L3+L4+L5+f(The first connect method)
L2+L3+L4+L5+f(The first connect method)
a,b,c,d,e
Total Pipe Length(Actual)
Pipe Length
Pipe Length(from the first line branch
pipe to furthest indoor unit)(m)
Indoor Unit-Outdoor
Unit Drop Height(H)
Outdoor Unit up
Outdoor Unit Down
Permitted value
≤50m(28
kBtu/h
)
≤65m(36/42
kBtu/h
)
≤100m(48/56
kBtu/h
)
≤20m
≤15m
≤10m
≤10m(28
kBtu/h
)
≤20m(36/42
kBtu/h
)
≤30m(48/56
kBtu/h
)
Piping
L1+L2+L3+L4+L5
+a+b+c+d+e+f
≤10m(28
kBtu/h
)
≤20m(36/42
kBtu/h
)
≤20m(48/56
kBtu/h
)
Drop HEIGHT
between indoor unit and outdoor unit
The first connect method
Indoor Unit
The First Line Branch Pipe
Outdoor unit
a
A
L2
L1
B
C
D
E
L3
L4
L5
b
c
d
e
f
Fig.4-7
Note: When the total equivalent piping length of gas side is ≥90m, it must increase the size of air side main pipe. Besides, according
to the distance of refrigerant pipe and the over matched state of inner unit, when the capacity is decreasing it still can increase the gas side
main pipe size.
≤35m(28
kBtu/h
)
≤45m(36/42
kBtu/h
)
≤60m(48/56
kBtu/h
)
≤40m(28
kBtu/h
)
≤50m(36/42
kBtu/h
)
≤70m(48/56
Btu/h
)
Drop Height
Pipe Length(from the nearest branch
pipe equivalent length(m)
Pipe length (From the nearest branch pipe equivalent length)
Maximum pipe equivalent length
(From the first line branch pipe) Maximum pipe equivalent length
Indoor Unit to Indoor Unit Drop Height
table 4-11