Bosch MDCI Series - Page 8

6 720 874 421 (2017/04) ZA Mini VRF Heat Pump Outdoor Unit
8 | INSTALLING THE CONNECTIVE PIPEWORK
• The second connection method
Indoor unit
a
N
1
3
N
5
N
6
N
2
N
4
N
Outdoor unit
A
B
D
E
C
b
c
e
f
d
1
L
2
L
5
L
3
L
4
L
Drop height between indoor unit and outdoor unit
Maximum equivalent pipe length
Equivalent pipe length to the nearest
branch.
(From the first line branch pipe)
Maximum equivalent pipe length
Indoor Unit to Indoor Unit Drop height
The First Line Branch Pipe
Fig. 4-8
4.7 Removing The Contaminants in the Pipework
Ensure pipework is clear from any water or dirt prior to connecting onto the
outdoor unit.
When cleaning pipework, use nitrogen to flush through the system. Do not
use refrigerant or water to clean the pipework.
4.8 Strength/Tightness Test
Pressure test the system with nitrogen to 44kgf/cm
2
. Ensure a 24 hour
strength test has been completed for all new installations. For guidance on
tightness testing for existing installations, please refer to F Gas Regulations.
CAUTION
1 Pressured nitrogen [4.3 MPa (44kg/cm
2
) for R410A] should be used
for strength testing.
2 The high pressure/low pressure valves must be closed when applying
pressured nitrogen.
4.9 Vacuuming the installation
• Use a vacuum pump to create the vacuum. do not use refrigerant to
expel air.
• Vacuuming should be done on liquid, gas and oil balance pipework.
4.10 Refrigerant Amount to be Added
Calculate the additional refrigerant to be added according to the diameter
and the length of the liquid side pipe.
• When the outdoor unit connects 1 indoor unit:
Table 4-12
Liquid Side Pipework
Diameter
Refrigerant to be Added
Per Meter Of Pipework
Ø6.4 0.022 kg
Ø9.5 0.054 kg
Ø12.7 0.110 kg
Ø15.9 0.170 kg
Ø19.1 0.260 kg
Ø22.2 0.360 kg
NOTE
Additional refrigerant volume of divergent pipe is 0.1 kg per meter
(Consider the liquid side of divergent pipe only)