17
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Piping installation
Installer and user reference guide
91
R R8T7V1B
VRV IV heat pump for indoor installation
4P499898-1A – 2020.10
17.4.3 To determine the additional refrigerant amount
Formula:
R=[(X
1
×
Ø12.7
)×0.12+(X
2
×
Ø9.5
)×0.059+(X
3
×
Ø6.4
)×0.022]×A+B
R
Additional refrigerant to be charged [in kg and rounded off to 1 decimal place]
X
1...3
Total length [m] of liquid piping size at
Øa
A+B
Parameters A and B
Parameters A and B
:
Model
A
B
RKXYQ5
0.8 kg
3.1 kg
RKXYQ8
1.0 kg
2.6 kg
Metric piping.
When using metric piping, replace the weight factors in the formula
by the ones from the following table:
Inch piping
Metric piping
Piping
Weight factor
Piping
Weight factor
Ø6.4 mm
0.022
Ø6 mm
0.018
Ø9.5 mm
0.059
Ø10 mm
0.065
Ø12.7 mm
0.12
Ø12 mm
0.097
17.4.4 To charge refrigerant
Charging refrigerant consists of 2 stages:
Stage
Description
Stage 1: Pre-charging
Recommended in case of larger systems.
Can be skipped, but charging will take longer then.
Stage 2: Manual charging
Only necessary if the determined additional
refrigerant amount is
not reached
yet by pre-
charging.
Stage 1: Pre-charging
Summary – Pre-charging
:
Refrigerant bottle
Connected to the service ports of the stop valves.
Which stop valves to use depends on the circuits you
choose to pre-charge to:
▪
Circuits 1 and 2 together (manifold with refrigerant
line splitters required).
▪
First circuit 1, then circuit 2 (or vice versa).
▪
Only circuit 1
▪
Only circuit 2
Stop valves
Closed
Compressor
Does NOT operate
1
Connect as shown (choose one of the possible connections). Make sure that
all compressor unit stop valves, as well as valve A are closed.
Possible connections:
