14 Piping installation
Installation and operation manual
25
RK RKXYQ8T7Y1B
VRV IV compressor unit for indoor installation
4P499900-1A – 2020.10
a
b
a
Insulation material
b
Caulking etc.
14.4
Charging refrigerant
14.4.1
Precautions when charging refrigerant
WARNING
▪ ONLY use R410A as refrigerant. Other substances
may cause explosions and accidents.
▪ R410A contains fluorinated greenhouse gases. Its
global warming potential (GWP) value is 2087.5. Do
NOT vent these gases into the atmosphere.
▪ When charging refrigerant, ALWAYS use protective
gloves and safety glasses.
NOTICE
If the power of some units is turned off, the charging
procedure cannot be finished properly.
NOTICE
Be sure to turn ON the power 6 hours before operation in
order to have power running to the crankcase heater and
to protect the compressor.
NOTICE
If operation is performed within 12 minutes after the
compressor unit, heat exchanger unit and indoor units are
turned on, the compressor will not operate before the
communication is established in a correct way between the
compressor unit, heat exchanger unit and indoor units.
NOTICE
Before starting charging procedures:
▪ In case of 5 HP: Check if the 7‑LEDs display is as
normal (see
30]), and there
is no malfunction code on the user interface of the
indoor unit. If a malfunction code is present, see
"19.1 Solving problems based on error codes"
38].
▪ In case of 8 HP: Check if the 7‑segment display
indication of the compressor unit A1P PCB is as normal
(see
30]). If a malfunction
code is present, see
"19.1 Solving problems based on
38].
NOTICE
Make sure all connected units (heat exchanger unit +
indoor units) are recognised (setting [1‑5]).
14.4.2
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
14.4.3
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:
Manifold
Connections
Compressor unit
p< p>
R410A
N2
b
c
e
a
d
B
A
Circuit 1 and 2
together
C
g
h
A
f
i
B
C
C
C
D
D
RDXYQ
RDXYQ
h
h
i
i
g
g
f
f
5 HP
8 HP
Only circuit 1
i
B
h
A
C
C
Only circuit 2
C
C
f
B
g
A
a
Pressure reducing valve
