VAV Controllers LVC-LowVelocity - TROX

5/5/EN/1
VARYCONTROL
VAV Controllers
Type LVC-LowVelocity
For low air velocities
The art of handling air

Contents
Innovation __________________________________ 3
Functional description__________________________ 4
Construction · Dimensions ______________________ 5
Nomenclature · Selection of nominal size __________ 6
Acoustic quick selection ________________________ 7
Air-regenerated noise __________________________ 8
Case-radiated noise __________________________ 9
Flow rate setting ______________________________10
Flow characteristics · Wiring examples ____________11
Order details ________________________________12
1 Select nominal size Set flow rates
2
3
Green light: Ready!
2

Innovation
TROX LVC-LowVelocity – the innovative solution
■
■
Optimised for low air velocities of 0.6 to 6 m/s
High control accuracy even in case of unfavourable
upstream flow conditions
■ Casing length of only 310 mm
■ Selection according to the nominal size of the duct
■ Indicator light provides functional information
The innovative concept of the type LVC-LowVelocity controllers
provides accurate measurement and control of low volume flow
rates based on the differential pressure principle.
The differential pressure is the result of two measurements,
one upstream and one downstream of the damper blade. This
setup makes it possible to measure larger differential pressures,
especially in the case of low volume flow rates. The relation
between damper blade position and differential pressure is
stored as a characteristic relationship in the Compact controller.
LVC-LowVelocity: simple, accurate, reliable!
1
2
3
9
8
4 5 6 7
1 Casing
2 Double lip seal
3 Plastic nozzle with damper blade
4 Flow rate scale
5 Wire clamping bracket
6 TROX Compact controller
7 Connection terminals
8 Protective cover
9 Indicator light
Potentiometers
Damper blade shaft end
(indicates blade position)
3

Functional description
Volume flow rate measurement
A new measurement principle makes it possible to measure
low volume flow rates. The pressure is measured by means
of a nozzle with tappings upstream and downstream of the
damper blade. The Compact controller of the LVC-LowVelocity
determines the resulting pressure differential (effective pressure)
and compares it to the stored characteristic.
This measurement principle is characterised by small measuring
tolerances, and the upstream flow conditions do not have to
meet any special requirements.
Volume flow rate control
The volume flow rate is controlled in a closed loop,
i.e. measurement – comparison – control.
First, measurement takes place. The controller then compares
the actual measured value to the setpoint value, which in most
applications is received from a room temperature controller. In
case of a deviation, the controller sends a signal to the actuator,
and the actuator moves the damper blade accordingly.
Room temperature control
In VAV systems, the room temperature control takes the form
of a cascade control. The room temperature is the primary
controlled variable. The output signal from the room temperature
controller controls the supply air flow rate. Flow rate control also
means defining minimum and maximum flow rates, and not only
does this help to keep the room temperature constant but has
advantages for the entire air conditioning system.
Supply/extract air tracking control
In individual rooms the balance between supply and extract air
should be maintained. Otherwise, annoying whistling noises
can occur at door gaps, and the doors can be difficult to open.
This is also why the extract air is controlled in a VAV system
(tracking control). The actual supply air value is fed to the
extract air controller, and the extract air consequently follows
the supply air flow rate even when the supply air deviates
from the setpoint value.
Control principle
Control diagram
V Nom
V max
2
3
1
Setpoint value
TROX Compact controller
Vmin
V min unit
1 Volume flow controller
2 Differential pressure transducer
3 Actuator
Control signal for the VAV controller
Upstream flow conditions
Upstream bend
Branch off the main duct
1 D
D
4

Construction · Dimensions
Characteristics
– Electronic flow rate control
– Suitable for supply and extract air
– High control accuracy, even in case of unfavourable upstream
flow conditions
– Differential pressure range: 30 to 600 Pa
– Shut-off by means of a switch (supplied by customer)
– Leakage when the damper blade is closed complies
with EN 1751, class 3
– Any installation orientation is possible
– Transparent protective cover for general safety and to prevent
inadvertent resetting
– Wire clamping bracket
– Factory setting and aerodynamic function testing of every
individual unit on a special test rig
Construction features
– Both spigot connections with lip seals, suitable for ducts
according to EN 1506 or EN 13180
– Casing air leakage complies with EN 1751, class C
– Mechanical parts of the VAV controller are maintenance-free
Materials
– Casing in galvanised sheet steel
– Nozzle, damper blade, and plain bearings made of
ABS plastic, UL 94, flame retardant (V0)
– Damper blade seal made of TPV plastic
General Information
Standard filtration in comfort conditioning systems is such that
the TROX Compact controller can be used in the supply air
without additional dust protection. To select volume flow
controllers for dust laden or aggressive extract air refer to the
Easy Product Finder design programme on our homepage.
Dimensions
310
50 50
300
Ø Da
300
20
76
Keep clear to provide access to
control components
Dimensions in mm
Nominal size ØDa
125 124
160 159
200 199
250 249
Weight in kg
Nominal size
125 1.5
160 1.9
200 2.1
250 2.7
TROX Compact controller – Technical data
Supply voltage
Power rating
Control signal
Flow rate actual value
signal
IEC protection class
Protection level IP 20
24 V AC ± 20 %, 50/60 Hz or
24 V DC −10 % / +20 %
5 VA max. (for AC voltage)
3 W max. (for DC voltage)
0 to 10 V DC, Ri > 100kΩ
0 to 10 V DC linear, 0.5 mA max.
III (Safety Extra Low Voltage, SELV)
5

Nomenclature · Selection of nominal size
Nomenclature
fm
in Hz : Octave band centre frequency
LPA in dB(A) : A-weighted sound pressure level of
air-regenerated noise, system
attenuation taken into account
LPA₁ in dB(A) : A-weighted sound pressure level of
air-regenerated noise in the room with
CS circular silencer, system attenuation
taken into account
LPA₂ in dB(A) : A-weighted sound pressure level of
case-radiated noise, system attenuation
taken into account
LW
in dB : Sound power level of the air-regenerated
noise in the duct
LW₂
in dB : Sound power level of the case-radiated
noise
V Nom in l/s and m³/h : Nominal flow rate (100 %)
V in l/s and m³/h : Volume flow rate
∆V in ± % : Flow rate tolerance from setpoint value
Vmin in l/s and m³/h : Set minimum volume flow rate
V max in l/s and m³/h : Set maximum volume flow rate
V min unit in l/s und m³/h : Minimum volume flow rate for unit
∆pst
in Pa : Static pressure differential
∆pst min in Pa : Static minimum pressure differential
All sound power levels are based on 1 pW, all sound pressure
levels on 20µPa.
All noise levels were determined in a reverberation chamber.
The sound power data has been determined and corrected
according to EN ISO 5135, February 1999.
Technical data based on an air density of 1.2 kg/m³.
10 20 30 40 50 60 70 80 90 100
Vmin
10 20 30 40 50 60 70 80 90 100
Air flow velocity
in m/s (approx.)
0.6 1.2 1.8 2.4 3.0 3.6 4.2 4.8 5.2 6.0
V max
Nominal
size
125
l/s 8 15 25 30 40 45 55 60 70 75
m³/h 30 55 80 110 135 160 190 215 245 270
160
l/s 12 25 35 50 60 70 85 95 110 120
m³/h 45 85 130 170 215 260 300 345 385 430
200
l/s 20 40 55 75 95 115 135 150 170 190
m³/h 70 135 205 275 340 410 480 550 615 685
250
l/s 30 60 90 120 150 180 210 240 270 300
m³/h 110 215 325 430 540 650 755 865 970 1080
6

Acoustic quick selection
Using quick selection for sizing VAV controllers will rapidly
provide optimum results. The first selection criteria are the given
volume flow rates Vmin and V max . The expected sound pressure
level in the room is then determined from the static pressure
differential. The quick selection tables are based on normally
accepted attenuation levels; if the sound pressure level exceeds
the required level, a larger volume flow controller and/or a
silencer is required.
For dimensions and technical data for type CS sound
attenuators refer to leaflet 6/5/EN/....
For a more detailed selection and design of
type LVC-LowVelocity VAV controllers refer to the
Easy Product Finder design programme on our homepage.
System attenuation in dB/oct. acc. to VDI 2081
(values incorporated in the quick selection table)
fm in Hz
63
Duct bend 0 0 1 2 3 3 3 3
Room attenuation 5 5 5 5 5 5 5 5
End reflection 10 5 2 0 0 0 0 0
125
250
500
Correction for distribution into the duct system
(values incorporated in the quick selection table)
V
1000
2000
4000
l/s 150 200 250 300
m³/h 540 720 900 1080
dB per octave 0 1 2 3
8000
4 dB/octave ceiling reduction and 5 dB/octave room attenuation
have been allowed for in the calculation of case-radiated noise.
Quick selection of sound pressure level LPA in dB(A)
Air-regenerated noise
Case-radiated
noise
Nominal
size
V
∆pst
min
∆V
∆pst in Pa ∆pst in Pa ∆pst in Pa ∆pst ∆pst in Pa
50 150 300 50 150 300 50 150 300 300 50 150 300
Without CS
CS050
L = 500
CS050
L = 1000
CS050
L = 1500
LPA LPA₁ LPA₁ LPA₁ LPA₂
l/s m³/h Pa ±% dB(A) dB(A) dB(A) dB(A) dB(A)
8 30 30 15 27 37 43 14 22 28 4 10 15 10 9 21 30
125
30 110 30 12 35 45 51 24 33 39 17 24 29 26 16 27 34
55 200 30 8 39 49 55 30 39 44 24 31 36 33 20 30 38
75 270 30 5 42 52 58 34 42 48 29 36 41 38 22 33 40
12 45 30 15 28 38 45 19 28 34 12 19 24 20 8 20 28
160
50 180 30 12 34 44 51 25 34 40 19 27 32 28 17 28 36
85 305 30 8 36 46 54 29 37 43 23 31 36 33 21 32 39
120 430 30 5 38 48 56 21 39 45 28 34 39 36 23 34 42
20 70 30 15 31 40 47 21 30 36 13 20 26 23 10 21 29
200
75 270 30 12 35 45 52 25 34 42 19 26 32 29 17 29 37
135 485 30 8 36 47 54 28 37 44 22 29 35 33 21 32 40
190 685 30 5 36 47 55 29 37 45 26 31 36 35 23 34 42
30 110 30 15 31 41 48 24 32 40 17 25 32 30 16 27 34
250
120 430 30 12 36 47 54 28 38 46 21 30 38 35 24 35 42
210 755 30 8 36 47 55 28 39 47 23 31 39 36 27 38 46
300 1080 30 5 36 48 55 29 39 48 25 32 39 37 29 40 48
7

Air-regenerated noise
1
LW₂
LW
2
LPA
LPA₁
3
4
5
Example
Given: V max = 50 l/s (180 m³/h)
∆pst = 150 Pa
Required sound pressure level in the
room 45 dB(A)
For further assumptions, see calculation
Calculation
Quick selection:
LVC-LowVelocity / 160
Air-regenerated noise
LPA = 44 dB(A)
Case-radiated noise
LPA₂ = 28 dB(A)
LPA₂
1 LVC-LowVelocity
2 Circular silencer CS/CF
3 Air distribution to several diffusers
4 Duct bend
5 End reflection based on diffuser
Nominal
size
V
Air-regenerated noise
∆pst = 50 Pa ∆pst = 150 Pa ∆pst = 300 Pa
LW in dB LW in dB LW in dB
fm in Hz fm in Hz fm in Hz
l/s
m³/h
63
125
250
500
1000
2000
4000
8000
63
125
250
500
1000
2000
4000
8000
63
125
250
500
1000
2000
4000
8000
8 30 42 29 29 36 27 16 4 7 44 36 39 45 39 31 17 22 45 41 45 50 47 41 26 31
125
30 110 55 47 44 43 33 27 19 14 57 54 53 52 45 42 32 29 59 59 59 58 53 51 41 38
55 200 61 55 50 47 36 31 26 17 63 62 59 55 48 46 39 32 65 67 65 61 56 56 47 41
75 270 64 59 54 49 38 34 30 19 67 67 63 57 50 49 43 34 68 71 69 63 57 58 51 43
12 45 41 30 40 36 27 19 22 7 45 68 47 45 39 35 35 25 47 43 51 50 46 45 43 37
160
50 180 49 45 46 40 34 27 26 13 53 53 53 49 45 43 39 32 55 58 58 55 53 53 48 44
85 305 52 51 48 42 36 31 28 16 56 59 56 51 48 46 41 35 58 64 60 57 56 56 49 46
120 430 54 55 50 44 38 33 29 18 58 63 57 52 50 48 42 36 60 68 62 58 57 58 50 48
20 70 42 31 40 39 30 23 19 8 44 39 46 48 41 38 34 24 45 44 50 53 48 48 53 35
200
75 270 53 44 44 42 36 30 24 14 55 52 50 50 47 45 39 30 56 58 54 56 54 55 48 41
135 485 58 49 45 43 38 33 26 16 60 58 51 51 49 48 41 33 61 63 55 57 56 58 50 43
190 685 61 52 46 43 40 35 28 18 63 61 52 52 51 50 42 35 64 66 56 57 58 60 52 45
30 110 35 33 43 38 31 28 20 13 42 41 49 46 42 42 37 30 46 47 52 51 49 50 47 41
250
120 430 47 45 45 41 37 37 25 18 54 53 51 49 48 50 42 35 58 59 55 54 55 58 52 46
210 755 52 50 46 42 40 40 27 20 58 58 52 50 50 53 44 37 62 64 56 56 57 62 54 48
300 1080 55 53 47 43 41 42 29 22 61 61 53 51 52 55 45 39 65 67 57 56 59 64 56 49
8

Case-radiated noise
Example (contd.)
Calculation of air-regenerated noise
fm 63 125 250 500 1000 2000 4000 8000
LW 53 53 53 49 45 43 39 32
Distribution 0 0 0 0 0 0 0 0
Duct bend 0 0 1 2 3 3 3 3
End reflection 10 5 2 0 0 0 0 0
Sound power level
to room
43 48 50 47 42 40 36 29
Room attenuation 6 6 5 5 4 4 4 4
A-weighting −26 −16 −9 −3 0 1 1 −1
Corrected level 11 26 36 39 38 37 33 24
LPA 44
Calculation of case-radiated noise
fm 63 125 250 500 1000 2000 4000 8000
LW₂ 30 23 25 29 33 32 25 24
Ceiling attenuation 4 4 4 4 4 4 4 4
Room attenuation 6 6 5 5 4 4 4 4
A-weighting −26 −16 −9 −3 0 1 1 −1
Corrected level 0 0 7 17 25 25 18 15
LPA₂ 29
In a variation from the quick selection, different room attenuation
values have been assumed.
The logarithmic addition of air-regenerated noise and
case-radiated noise equals 44 dB(A) and does therefore not
exceed the required sound pressure level of 45 dB(A).
Nominal
size
V
Case-radiated noise
∆pst = 50 Pa ∆pst = 150 Pa ∆pst = 300 Pa
LW₂ in dB LW₂ in dB LW₂ in dB
fm in Hz fm in Hz fm in Hz
l/s
m³/h
63
125
250
500
1000
2000
4000
8000
63
125
250
500
1000
2000
4000
8000
63
125
250
500
1000
2000
4000
8000
8 30 25 6 7 12 14 4 7 13 26 14 16 20 24 18 21 28 27 18 21 26 30 26 29 38
125
30 110 28 18 19 21 22 15 13 10 29 25 27 29 32 29 27 25 30 30 33 35 38 37 35 35
55 200 29 23 24 25 26 20 16 8 31 30 32 33 35 33 29 24 31 35 38 39 42 42 38 33
75 270 30 26 27 27 28 23 17 7 31 33 36 36 37 36 31 23 32 38 41 41 44 45 40 33
12 45 24 5 6 12 15 9 3 4 26 10 13 20 25 22 19 22 28 13 18 25 31 30 28 33
160
50 180 28 18 18 21 24 19 9 7 30 23 25 29 33 32 25 24 31 26 30 34 40 40 35 36
85 305 29 23 22 24 27 23 12 8 31 28 30 32 37 36 28 26 33 31 35 37 43 44 38 37
120 430 30 27 25 26 30 25 14 9 32 32 33 34 39 38 29 26 34 35 38 39 45 47 39 38
20 70 26 10 14 19 13 8 4 7 28 16 20 28 24 22 19 22 29 19 24 34 31 31 29 32
200
75 270 29 19 21 25 22 18 11 9 31 24 27 34 33 32 26 24 32 27 31 39 40 41 36 34
135 485 30 22 24 27 26 22 14 9 32 28 30 36 37 36 29 25 33 31 34 42 43 45 39 34
190 685 31 25 26 28 28 25 15 10 33 30 32 37 39 39 31 25 34 33 36 43 46 48 40 35
30 110 24 13 8 19 23 18 11 2 26 17 17 27 32 30 26 21 28 20 22 32 38 38 36 33
250
120 430 28 22 18 25 30 27 17 7 31 27 27 33 39 40 33 26 32 30 32 38 45 47 43 38
210 755 30 26 22 27 33 31 20 9 32 30 31 35 42 44 35 28 34 33 36 40 48 51 45 40
300 1080 31 28 25 29 35 34 22 10 34 33 33 37 44 46 37 29 35 36 38 42 50 54 47 41
9

Flow rate setting
Each LVC-LowVelocity carries a sticker with a flow rate scale to
determine the setting values at the customer’s site (see example
above, nominal size 200).
Variable flow rate control
The required flow rates must be set by the customer. If Vmin is
set higher than V max , Vmin is provided as a constant flow rate
even if a control signal is transmitted.
If Vmin is set to 0%, control is between shut-off and V max . If the
control signal falls below 0.1 VDC, the control damper closes
(leakage flow only).
Vmin
V max
Constant flow rate control
The constant flow rate is set with the Vmin potentiometer. Any
setting on the V max potentiometer is in this case irrelevant.
Vmin
V max
BMS operation
To have the BMS determine the volume flow rate, the Vmin
potentiometer must be set to 0% and the V max potentiometer
to 100%. If the control signal falls below 0.1 VDC, the control
damper closes (leakage flow only).
Vmin
V max
Factory setting
Units are delivered with settings Vmin = 40 % and
V max = 80%.
Vmin
V max
10

Flow characteristics · Wiring examples
Characteristics of the control signal (example)
Characteristics of the actual value signal
V min unit V Nom V min unit V Nom
Value to be set =
V
V Nom
× 100 %
Control signal w in V
Actual value signal U in V
Volume flow rate in % of V Nom
Volume flow rate in % of V Nom
Variable flow rate control
Room temperature
controller
The supply voltage and the remote room temperature
controller must be connected as shown in the circuit
diagram on the left.
TROX Compact
Constant flow rate control
As soon as the 24 V supply voltage is applied, the controller
runs the set Vmin value as a constant flow rate.
TROX Compact
Changeover V min / V max
S1
TROX Compact
Override controls OPEN / CLOSED
S2
S3
Diode 1N 4007
TROX Compact
Switch S1 enables a changeover between the two constant
flow rates Vmin and V max .
Switch S1 open : Vmin
Switch S1 closed : V max
When multiple LVC-LowVelocity units are connected in
parallel, switch S1 must be used as changeover switch and
the contact for Vmin operation must be connected to the
ground (terminal 1).
The override controls for OPEN and CLOSED (see left)
can be achieved using external switches (potential-free
contacts); this applies to AC voltage only.
Switch S2 closed: Damper blade CLOSED
Switch S3 closed: Damper blade OPEN
All override controls can be combined both with each other
and with the different circuit options. All connections and
wiring done by the customer must comply with the generally
accepted standards of good practice and any specific local
standards.
11

Order details
Specification text
Circular VAV circular controllers of type LVC-LowVelocity for
low velocities in variable air flow systems, suitable for supply
or extract air, available in 4 nominal sizes.
Measurement and control of low volume flow rates based on
a new measurement principle. Plastic nozzle with damper
blade for measuring the differential pressure, or effective
pressure, upstream and downstream of the damper blade.
The relation between differential pressure and damper
blade position is stored in the TROX Compact controller
such that a high control accuracy is achieved even in case
of unfavourable upstream flow conditions.
Special characteristics
– Optimised for low air velocities of 0.6 to 6 m/s
– High control accuracy even in case of unfavourable
upstream flow conditions
– Easy flow rate setting without additional equipment
– Factory setting and aerodynamic function testing of every
individual unit on a special test rig
Selection based on nominal size determination. The
customer can easily set volume flows Vmin and V max on the
potentiometers with percentage scales during installation or
commissioning. No supply voltage is required for this. A
transparent protective cover prevents inadvertent resetting
and provides general safety. The control damper blade is set
to 45° ex factory, which allows ventilation air flow without
control.
Differential pressure range 30 to 600 Pa.
The averaging differential pressure sensor is resistant to
dust and pollution.
Air leakage when the damper blade is closed complies
with EN 1751, class 3. The position of the damper blade is
indicated on the outside by the damper blade shaft end.
Variable flow rate control with factory mounted electronic
Compact controller to switch an external control signal;
actual value signal can be integrated into BMS.
24 V AC/DC supply voltage
Electrical connections with screw terminals. Double terminal
for looping the 24 V supply voltage, i.e. for the simple
connection of voltage transmission to the next controller.
Wire clamping bracket fixed to the casing.
Voltage range for control and actual value signal
0 to 10 V DC. Possible override controls with external
switches using potential-free contacts: OPEN, CLOSED,
Vmin and V max .
Clearly visible external indicator light for signalling the
functions:
Set, not set and power failure.
Materials
Casing made of galvanised sheet steel. Nozzle, damper
blade, and plain bearings made of ABS plastic, UL 94, flame
retardant (V0). Damper blade seal made of TPV plastic.
Order code
LVC-LowVelocity
/
160
Subject to change · All rights reserved © TROX GmbH (3/2011)
ype
Nominal size
125
160
200
250
Order example
Make: TROX
Type: LVC-LowVelocity / 160
12