106
10
REFRIGERANT PIPING TASKS
Line-Branch Method
Connection Examples
(Connecting to Four Indoor Units)
Liquid Line
Gas Line
Piping Diameter (mm)
Model
PUMY-71
PUMY-125
{
9.52
{
15.88
Liquid Line (mm)
Gas Line (mm)
Downstream Unit Model Total
80 or less
80 or more
{
15.88
{
19.05
{
9.52
{
9.52
Liquid Line
Gas Line
Liquid Line
Gas Line
Liquid Line
Gas Line
Piping Diameter (mm)
Model number
40 or lower
100, 125
50 to 80
{
6.35
{
12.7
{
9.52
{
15.88
{
9.52
{
19.05
Outdoor Unit
First Branch
Indoor unit
A
B
C
A+B+C+a+b+c+d is 100 meters or less (125 Type), 80 meters or less (71 Type)
A+B+C+d is 70 meters or less (125 Type), 50 meters (71 Type)
B+C+d is 30meters or less
30 meters or less (If the outdoor unit is lower, 20 meters or less)
12 meters or less
Use an optional branch piping kit (CMY-Y62-C-E).
Total Piping Length
Farthest Piping Length
Farthest Piping Length After First Branch
High/Low Difference in Indoor/Outdoor Section
High/Low Difference in Indoor/Indoor Section
Permissible
Length
Permissible High/
Low Difference
(L)
(
R
)
(H)
(h)
■
Selecting the Refrigerant Branch Kit
■
Select Each Section of Refrigerant Pipng
■
Additional refrigerant charge
Select the size from the table to the right.
(1) Refrigerant Piping Diameter In Section
From Outdoor Unit to First Branch (Out-
door Unit Piping Diameter)
(1) Section From Oudoor Unit
to First Branch (A)
(2) Sections From Branch to
Indoor Unit (a,b,c,d)
(3) Section From Branch to
Branch (B,C)
(3) Refrigerant Piping Diameter In Section
From Branch to Branch
(2) Refrigerant Piping Diameter In Section
From Branch to Indoor Unit (Indoor Unit
Piping Diameter)
Each
Section of
Piping
• Refrigerant of 3kg equivalent to 50-m total
extended piping length (model 125) or 2.4kg
equivalent to 40-m (model 71) is already in-
cluded when the outdoor unit is shipped.
Thus, if the total extended piping length is
50m or less (model 125) or 40m or less
(model 71), there is no need to charge with
additional refrigerant.
• If the total extended piping length exceeds
50m (model 125) or 40m (model 71), calcu-
late the required additional refrigerant charge
using the procedure shown on the right.
• If the calculated additional refrigerant charge
is a negative amount, do not charge with any
refrigerant.
<Additional Charge>
<Example>
Outdoor model : 71
Indoor 1 : 25
A :
{
9.52 10m
a :
{
6.35
5m
2 : 20
B :
{
9.52 10m
b :
{
6.35
10m
3 : 25
C :
{
9.52 10m
c :
{
6.35
10m
4 : 20
d :
{
6.35
10m
The total length of each liquid line is as follows
{
9.52 : A + B + C = 10 + 10 +10 = 30m
{
6.35 : a + b + c + d = 5 + 10 + 10 + 10 = 35m
Therefore,
<Calculation example>
Additional
refrigerant charge = 30
✕
0.06 + 35
✕
0.024 – 2.4 = 0.3kg (rounded up)
Additional
refrigerant charge
(kg)
Liquid pipe size
Total length of
{
9.52
✕
0.06
(m)
✕
0.06 (kg/m)
=
Liquid pipe size
Total length of
{
6.35
✕
0.024
(m)
✕
0.024 (kg/m)
+
Refrigerant
amount for outdoor
unit
71: 2.4kg
125: 3.0kg
–
At the conditions
below:
Liquid Line
Gas Line
{
9.52
{
19.05
B
A
a
b
C
C
C
c
C
d
C
L
1
2
3
4
H
h
R
A
B
10-1. REFRIGERANT PIPING SYSTEM
OC183E--4.qxp 10.5.6 0:54 PM Page 106
