12 Special requirements for R32 units
Installation and operation manual
18
BS4~12A14AJV1B
VRV 5 branch selector unit
4P670163-1 – 2022.02
Use the curves, with instructions how to read them, of the
manufacturer of the components to find the pressure drop generated
by all components in the ductwork. A conversion of units might be
required. Beware that for ducting, the pressure drop from the
manufacturer might be given per unit length of ducting (units are for
example Pa/m). Multiply this value by the duct length to find the total
pressure drop.
AFR
[m³/h]
AFR
[m³/h]
ΔP
[Pa/m]
ΔP
[Pa]
115
1
115
8
Ducting
Bends
EXAMPLE
Note down the pressure drop of each component in an overview
table. Sum up the pressure drops.
Nº
Indication
Type
AFR (m³/h)
Length (m)
∆P (Pa/m)
∆P (Pa)
1
a
BS unit
115
-
-
47.5
2
b
Duct
“
5
1
5
3
c
Bend
“
-
-
8
4
b
Duct
“
10
1
10
5
c
Bend
“
-
-
8
6
b
Duct
“
2
1
2
7
d
Expander
“
-
-
4
8
e
Duct
“
6
0.5
3
9
f
Reducer
“
-
-
6
10
b
Duct
“
2
1
2
11
b
Duct
“
1
1
1
12
g
Non-return valve
“
-
-
11
13
b
Duct
“
1
1
1
14
h
Wall grill
“
-
-
15
Total pressure drop (sum of rows 1 to 14)
123.5
Select a fan with the required flow of 115 m³/h and a total pressure
rise of 123.5 Pa.
Note:
For ease of installation we recommend to use in-line duct
fans.
BS unit test run
Before BS unit operation, it is required to perform a test run that
simulates a refrigerant leak. See
38] for
more details.
Field settings
Single BS unit – one extraction fan
Code
Description
Value
[2-0]
Cluster indication
0 (default): disable
[2-4]
Safety measures
1 (default): enable
[2-7]
Ventilated enclosure
1 (default): enable
Note:
Some field settings need to be made on all main PCB's (A1P,
A2P and A3P) of the same BS unit. For more information, see
34].
Multiple BS units in parallel – one extraction fan
In this configuration, multiple parallel BS units are connected to a
single extraction fan. Each BS unit benefits from a direct airflow path
to the extraction fan. In case of a refrigerant leak in any BS unit, the
damper of that BS unit will open and allow direct air evacuation to
the extraction fan. The dampers of the other BS units remain closed.
a
1
a
2
a
...
b
c
a
#
BS unit #
b
Ductwork
c
Extraction fan
It is sufficient to connect the extraction fan circuit to only 1 BS unit of
the cluster (=BS units that belong to the same ductwork and
extraction fan) (see
"15.5 To connect the external outputs"
34]). If
in a cluster there are BS units that belong to different outdoor unit
systems, the fan circuit must be connected to 1 BS unit (in the
cluster) of each outdoor unit system.
Example
a
a
a
A
c
e
c
e
d
e
e
f
b
a
a
A
c
e
d
e
d
e
e
B
e
f
a
BS unit belonging to outdoor unit A
b
BS unit belonging to outdoor unit B
c
Extraction fan output terminal – NOT connected
d
Extraction fan output terminal – connected
e
Transmission wiring terminal
f
Extraction fan
A
Outdoor unit A
B
Outdoor unit B
Transmission wiring
Extraction fan output wiring
An online tool (
) is available to find the required pressure
capacity for selecting the correct fan size. Only use this online tool
for the calculation.
BS unit test run
Before BS unit operation, it is required to perform a test run that
simulates a refrigerant leak. See
38] for
more details.
Field settings
Multiple BS units in parallel – one extraction fan
Code
Description
Value
[2-0]
Cluster indication
1: enable
[2-1]
Cluster number
#
(a)
[2-2]
Cluster configuration
0 (default): parallel
[2-4]
Safety measures
1 (default): enable
[2-7]
Ventilated enclosure
1 (default): enable
(a)
Assign a unique cluster number to each cluster in the system. All
BS units in the same cluster MUST have the same cluster
number.
Note:
Some field settings need to be made on all main PCB's (A1P,
A2P and A3P) of the same BS unit. For more information, see
