Volumetric flow controller VAQS
®
08/23 - 3
Construction subject to change. No return possible!
09.05.2019Version:
Description
The VAQS
®
volumetric flow controller impresses with its simple
design, high measuring precision and short length, meeting the
majority of customary requirements of volumetric flow control-
lers.
The volumetric flow controller allows the volumetric flow in
ducts to be kept constant or to be regulated using positive con-
trol V
min
, V
max
, "OPEN" or "CLOSED". The volumetric flow con-
troller can also be used as a room or duct pressure regulator. In
VAV systems the volumetric flow controller can regulate varia-
ble volumetric flows between V
min
and V
max
as a function of the
supply air (room temperature controller). The volumetric flow
setpoints V
min
and V
max
can also be altered at the controller at
a later stage, even after installation. Setpoints are initially set in-
factory according to the customer's requirements. If these val-
ues are set ex factory, the functions of the volumetric flow con-
troller are also checked. The V
min
and V
max
values can range
from 0 to 100 % (with V
min
) and 30 to 100% (with V
max
). The
measuring deviation is ± 5 %, based on V
nom
. Volumetric flow
controllers are in general insensitive to the inflow, owing to the
built-in measuring rods. 6 measuring points are distributed on
these measuring rods according to the median line method. In
comparison with measuring rods having only four measuring
points or measuring orifices, this gives optimum measurement
results.
When using the controllers in systems with heavy dust contam-
ination, suitable filters must be connected upstream. For pollut-
ed air, the volumetric flow controllers must be used with an
integrated controller with a static membrane pressure sensor. In
this case, it is absolutely necessary to observe the mounting po-
sition.
The volumetric flow controllers re not suit ble for ir con-
t ining sticky nd gre sy components.
For maintenance, service, retrofitting, etc., inspection openings
in sufficient number and size must be provided on site.
- simple design in accordance with the nominal size of the air
duct.
This simple design saves a lot of time and provides planning
safety.
- high controlling precision
Due to its high controlling precision, the controller requires a
straight flow section of only 1 x D even after bends.
- Blades sealing airtight to DIN EN 1751, Class 3
- Housing leakage air flow to DIN EN 1751, class B
- Damper axle support made of maintenance-free plastic
- in-factory presetting of the controllers
The controllers have been calibrated and preset in factory:
this in-factory presetting eliminates later setting operations
on-site. However, if a change must be made later on, the V
min
and V
max
settings can be simply adjusted using the ZTH-EU
setting device. For the calibration of the controllers, a curve
with a flow rate of 12 m/ sec is available. For constant-volume
volumetric flow controllers, the V
min
value will be set to the
desired constant-volume value.
- Tamper-proof
Since an on-site change in the volumetric flows can only be
done via the ZTH-EU, the controller is tamper-proof. Simple
rotary potentiometers are not tamper-proof!
- no later on-site volumetric flow controller setting necessary.
By virtue of the in-factory presetting, the on-site builder saves
the time required for on-site setting of the volumetric flow
controllers. Accordingly, the responsibility for setting the vol-
umetric flow controllers is not just passed on to the on-site
builder. This also reduces the on-site time pressure, since the
controllers do not have to be set on-site.
- Functional check possible via the ZTH-EU device.
The VAQS
®
volumetric flow controllers have already been
checked in-factory for their function. When the amount of air
changes on-site, a functional check can simply be carried out
by using the ZTH-EU device.
-
simple change in the amount of air via the ZTH-EU setting de-
vice
If the amounts of air preset in-factory must be adapted on-
site, this can be simply done by using the ZTH-EU device.
When the controllers are mounted in false ceilings, the ZTH-
EU can be simply inserted, and the setting and check can be
done comfortably inside the room. This is an advantage com-
pared with changing the settings of potentiometers, because
the potentiometers in false ceilings are often hard to get to
and difficult to see. If the changes in air volume are so large
that the calibration curve must be changed, the controllers
must either be recalibrated in-factory or the calibration curve
must be changed on-site by the customer service of Schako.
- Covers the majority of customary requirements
V
min
, V
max
and V
konstant
controls possible, as well as positive
control “Closed“ or positive control “Open“.
- Simple to connect
The controller contains the electrical wiring information. This
avoids wiring faults.
- Protection type IP 5
The controllers have the protection type IP 5 . A strain relief
for the cables has been integrated. For lower protection types,
e.g. IP 20, mounting into ventilation systems or central units
is not recommended.
