14
8.6 pipe selection and how to calculate
Main
tube
of unit
1st b
ranch
Unit distributio
n t
ub
e
LB
LA
L1
L2
LC
LD
ln
H1
H2
L3
l
1
l
2
l
5
l
n1
Caution:Do not use commercially available distribution joint for the liquid tubing. Be sure to use special
R410A disribution joints which supplied by Airwell only.(Part No. 463750190)
Chart 26
■ Ranges that apply to refrigerant tubing lengths and differences in installation heights.
Items
Marks
Contents
Length(m)
Allowable
tubing
length
L1
Max. tubing length
Actual tubing length
≤150
Equivalent tubing length
≤175
LA
Max. tubing length
≤80
L(L2-L3)
Difference between the max. length and the min.
length from the NO.1 distribution joint
≤40
l1,l2~ln
Max. length of each distribution tube
≤30
l1+l2+~ln-1+L1 Total max. tubing length including length of each
distribution tube(only narrow tubing)
≤200
Allowable
elevation
difference
H1
When outdoor unit is installed higher than indoor unit
≤50
when outdoor unit is installed lower than indoor unit
≤40
H2
Max. difference between indoor units
≤15
Table 8
L1 – Maximum allowable tube length;
L2 – Maximum tubing length from the first distribution;
L3 – Minimum tubing length from the first distribution;
LA – Main tube of the unit between the ODU and the first distribution;
8 refrIGerANT pIpING
