4 Preparation
Installation and operation manual
12
RWEYQ8~RWEYQ8~14T9Y1B
VRV IV water-cooled system air conditioner
4P452190-1A – 2017.04
To activate the variable flow system, change field setting [2-24] to
the applicable value. See
"6.1 Making field settings" on page 23
.
NOTICE
Make sure that all field supplied equipment for variable
flow rate can be switched off together with the outdoor unit.
This is required when cleaning the plate heat exchanger.
NOTICE
Make sure that all field supplied equipment for variable
flow rate meet the minimum hydronic and electric
specifications. Failure to do so can result in inefficient
operation or even breakdown of the system.
Size the valve (b) or pump (c) in accordance with the maximum
required flow rate A, calculated by the installer of the hydronic
system (with respect to the operation range of the outdoor unit). The
typical operation range of the flow rate of the valve/pump is 50% (B)
to 100% (A).
The valve/pump input signal is based on a variable 2~10 V DC
control output signal coming from the outdoor unit. The valve or
pump should have a linear control characteristic between unit output
signal and flow rate according to the example graph below.
0%
B
E
D
C
c
a
b
A
50%
100%
2 V DC
10 V DC
a
Valve/pump flow rate
b
Unit/system flow rate
c
Valve/pump input signal
A
Maximum required flow rate (100%)
B
50% of the maximum required flow rate
C
Minimum flow rate (see description below)
D
Maximum flow rate (see description below)
E
Hydronic flow rate
Follow the design criteria below to select the correct valve for the
system. The valve system maximum required flow rate
A
is a
property of the supplied valve and the 50% flow rate
B
is directly
related to the maximum flow rate of the system.
INFORMATION
Some third party valves/pumps have a maximum flow rate
defined by the hardware of the system, but a different
maximum flow rate can be set to correspond with the
maximum input voltage (10 V DC) The installer should ask
information to the valve/pump supplier before making the
selection.
Design criteria
1
Minimum flow rate
C
:
Model
C
RWEYQ8~12
50 l/min
RWEYQ14
75 l/min
2
Maximum flow rate
D
:
Model
D
RWEYQ8~12
120 l/min
RWEYQ14
190 l/min
3
Hydronic flow rate
E
:
The value
E
is the design flow rate calculated by the hydronic
engineer when designing the building system.
Correct valve selection is done when following conditions are met:
(B≥C) AND (E≤A≤D)
For further selection requirements, refer to
"4.4 Preparing electrical
wiring" on page 12
.
Check the minimum flow rate of the system during commissioning to
ensure good operation.
During the initialization process of the outdoor unit, the output signal
will trigger a flow rate of
B
(50%). The installer should make sure
that a flow rate can be checked in the individual hydronic system of
each unit. If this value is not matching the required flow, the installer
should troubleshoot the hydronic system to solve the problem and
ensure the correct flow rate.
4.4
Preparing electrical wiring
4.4.1
Safety device requirements
The power supply must be protected with the required safety
devices, i.e. a main switch, a slow blow fuse on each phase and an
earth leakage protector in accordance with the applicable legislation.
For single models
Selection and sizing of the wiring should be done in accordance with
the applicable legislation based on the information mentioned in the
table below.
Model
Minimum
circuit
ampacity
Recommended
fuses
RWEYQ8~14T9
22.3 A
25 A
For all models:
▪ Phase and frequency: 3N~ 50 Hz
▪ Voltage: 380~415 V
▪ Transmission line section: 0.75~1.25 mm
2
, maximum length is
1000 m. If the total transmission wiring exceeds these limits, it
may result in communication error.
For free combinations
Calculate the recommended fuse capacity.
Formula
Calculate, by adding the minimum circuit amps of each
used unit (according to the table above), multiply the
result by 1.1 and select the next higher recommended
fuse capacity.
Example
Combining the RWEYQ30T9 by using the RWEYQ8T9,
RWEYQ10T9, and RWEYQ12T9.
▪ Minimum circuit ampacity of the RWEYQ8T9=16.1 A
▪ Minimum
circuit
ampacity
of
the
RWEYQ10T9=22.0 A
▪ Minimum
circuit
ampacity
of
the
RWEYQ12T9=24.0 A
Accordingly, the minimum circuit ampacity of the
RWEYQ30T9=16.1+22.0+24.0=62.1 A
Multiply the above result by 1.1
⇒
(62.1×1.1)=68.31 A
⇒
the recommended fuse capacity would be
80 A
.
NOTICE
When using residual current operated circuit breakers, be
sure to use a high-speed type 300 mA rated residual
operating current.
