17
8 refrIGerANT pIpING
8.7 Additional refrigerant charge calculation
Additional refrigerant charge amount is calculated from the liquid tubing total length as follows.
Calculate the amount of refrigerant charge per meter according to liquid tubing size:
Liquid tubing size
Amount of refrigerant charge(g/m)
Φ 6.35
25
Φ 9.52
55
Φ 12.7
120
*Always charge accurately using a scale of weighing ,so
The required additional refrigerant charge (kg)=(25Xa+55Xb+120Xc)X10
-3
a: Total length of Φ6.35(mm) liquid tube
b: Total length of Φ9.52(mm) liquid tube
c: Total length of Φ12.7(mm) liquid tube
Following table offers the refrigerant charge amount at shipment (for outdoor unit):
Heat Pump Unit (kg)
112
140
160
4.5
5.5
6.5
Table
13
Table
14
Chose outdoor unit model as YAV140 (14KW
）
is the most economical.
(
3
)
Pipe calculation and selection
：
Pipe number
Actual length
（
m
）
Sum of nominal capacity after
every branch (KW
）
Pipe select result
Gas pipe/liquid pipe (mm
）
According as
LA
80
18.1
Φ19.05/Φ12.70
Table 9
LB
10
13.6
Φ15.88/Φ9.52
Table 10
LC
10
11.4
Φ15.88/Φ9.52
Table 10
LD
20
7.8
Φ15.88/Φ9.52
Table 10
l 1
30
--
Φ12.7/Φ6.35
Table 11
l 2
5
--
Φ12.7/Φ6.35
Table 11
l 3
5
--
Φ12.7/Φ6.35
Table 11
l 4
10
--
Φ12.7/Φ6.35
Table 11
l 5
30
--
Φ12.7/Φ6.35
Table 11
(
3
)
Additional refrigerant charge calculation (Please refer to chapter 9.6)
：
Liquid pipe size
(mm)
Length
（
m
）
Unit charge (g/m)
Total chage (kg)
Φ 6.35
80
25
2
Φ 9.52
40
55
2.2
Φ 12.7
80
120
9.6
Then the system need to add 13.8kg refrigerant R410A.
