4 Preparation
Installation manual
18
RWEQ96~432TAYD
∗
+ RWEQ96~432TATJ
∗
VRV W T-Series water-cooled system air conditioner
Before starting a test run
1
Before starting a test run, please make sure that the piping
work has been carried out in a proper manner. Especially, make
sure that the strainer, air discharge valve, automatic water
supply valve, expansion tank and cistern are positioned at their
places correctly.
2
After water has been completely filled in, first run the pump
only, and then make sure that no air has been caught in the
water circulation system and that the water flow rate is correct.
If any air has been caught or the flow rate is not enough, the
plate-type heat exchanger may freeze. Measure any water
pressure loss before and after the outside unit and make sure
that the flow rate is as designed. In case of any abnormality,
stop the test run immediately and carry out trouble shooting to
resolve the trouble.
3
Following the installation manual, carry out a test run of the
outside unit.
4
After the test run has been completed, inspect the strainer at
the inlet piping of the outside unit. Clean it if it is dirty.
a
b c
d
e
f
g
h
i
a
Water inlet piping
b
Strainer (accessory)
c
Air discharge valve (for joint use with cleaning port)
d
Cleaning device
e
Strainer for pump (field supply)
f
Automatic air discharge valve
g
Water outlet piping
h
Joint use with water draining plug
i
Plate-type heat exchanger
4 .4 .4
Variable water flow rate
The RWEQ96~144T
∗
models are equipped with the logic to operate
with a variable water flow rate function.
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 36.
NOTE
Make sure that all field supplied equipment for variable
flow rate can be switched off together with the outside unit.
This is required when cleaning the plate heat exchanger.
NOTE
▪ 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.
▪ The outside unit is equipped to deliver variable flow
signal to one hydronic pump. Hence it is recommended
to install only one hydronic pump per single module 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 outside 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 2~9 V DC control
output signal coming from the outside 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
9 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 (9 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
RWEQ96~144
13.2 gpm (50 l/min)
21.2 gpm (80 l/min)
(a)
(a) For antifreeze use
01_EN_4P602454-1C.indd 18
2020/07/29 16:16:41
