5 Preparation
Installer and user reference guide
21
RWEYQ8~1 RWEYQ8~14T9Y1B
VRV IV water-cooled system air conditioner
4P452191-1 – 2017.04
a
b
c
a
Constant flow
b
Flow regulating valve (field supply)
c
Inverter pump (field supply)
A system can either be configured as a constant flow system (a), a
variable flow system with valve (b) or a variable flow system with a
pump (c).
▪ Constant flow system (a): the variable water flow rate function is
not used.
▪ A pressure independent flow regulating valve (b): the valve
controls the flow rate of a centralized inverter pump through the
unit.
▪ Inverter pump (c): the pump directly controls the water flow rate
through the unit.
To activate the variable flow system, change field setting [2-24] to
the applicable value. See
"7.2 Making field settings" on page 35
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
.
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.
5.5
Preparing electrical wiring
5.5.1
About electrical compliance
This equipment complies with:
▪
EN/IEC 61000‑3‑12
provided that the short-circuit power S
sc
is
greater than or equal to the minimum S
sc
value at the interface
point between the user's supply and the public system.
▪ EN/IEC
61000‑3‑12
=
European/International
Technical
Standard setting the limits for harmonic currents produced by
equipment connected to public low-voltage systems with input
current >16 A and ≤75 A per phase.
▪ It is the responsibility of the installer or user of the equipment to
ensure, by consultation with the distribution network operator if
necessary, that the equipment is connected only to a supply
with a short-circuit power S
sc
greater than or equal to the
minimum S
sc
value.
Model
Minimum S
sc
value
RWEYQ8~14T9
1780 kVA
Because of the free multi combination, it is the responsibility of the
installer to calculate the minimum S
sc
value for the multi combination.
The value is calculated by adding up the values of the corresponding
units
used
in
the
multi
combination.
RWEYQ28T9=2×
RWRWEYQ8T9.