VFC

CAV controller variant VFC, with rotary knob

Variant with rotary knob

Actuator with mechanical stops

Actuator with potentiometers

Conforms to VDI 6022

For low airflow velocities

Circular mechanical self-powered volume flow controllers for the control of supply air or extract air in constant air volume systems with low airflow velocities
■ Suitable for airflow velocities from 0.8 m/s
■ Very simple commissioning
■ Volume flow rate can be set using a rotary knob and a scale on the outside of the casing
■ Simple retrofit of an actuator for variable volume flows
■ Any installation orientation; maintenance-free
■ Casing air leakage to EN 1751, class C

Optional equipment and accessories
■ Circular silencer CA (for Germany and Switzerland), CAH (for EMEA) or CF for the reduction of air-regenerated noise
■ Hot water heat exchanger WL and electric air heater EL for reheating the airflow
■ Actuator for variable volume flows or for qᵥmin-qᵥmaxswitching

General information

Application

Circular CAV controllers of Type VFC for the precise supply air or extract air flow control in constant air volume systems
Mechanical self-powered volume flow control without external power supply
For low airflow velocities
Simplified project handling with orders based on nominal size

Special characteristics

The volume flow rate can be set using an external scale; no tools required
Simple retrofitting of an actuator
Correct operation even under unfavourable upstream or downstream conditions (1.5 D straight section required upstream)
Any installation orientation
Aerodynamic functional testing of each unit on a special test rig before shipping

Nominal sizes

80, 100, 125, 160, 200, 250

Parts and characteristics

Ready-to-commission controller
Damper blade with low-friction bearings
Bellows that acts as an oscillation damper
Leaf spring
Rotary knob with pointer for setting the volume flow rate
Lip seal

Attachments

Min/Max actuators: Actuators for switching between minimum and maximum volume flow rate setpoint values
Modulating actuators: Actuators for varying volume flow rates

Useful additions

Circular silencers CA (for Germany and Switzerland) and CAH (for EMEA)
Heat exchanger WL
Electric air heater EL
Useful additions have to be ordered separately

Construction features

Circular casing
Spigot with lip seal, for circular connecting ducts to EN 1506 or EN 13180
Damper blade with low-friction bearings and special bellows

Materials and surfaces

Casing made of galvanised sheet steel
Damper blade and other parts made of high-quality plastic, to UL 94, V1; to DIN 4102, fire rating class B2
Leaf spring made of stainless steel
Polyurethane bellows

Standards and guidelines

Meets the hygiene requirements of VDI 6022
Casing air leakage to EN 1751, class C

Maintenance

Maintenance-free as construction and materials are not subject to wear

Technical information

Schematic illustration of the VFC 00132975_0

1 Damper blade
2 Leaf spring
3 Volume flow rate scale
4 Rotary knob locking screw
5 Rotary knob
6 Lip seal
7 Diagram with setting values
8 Bellows inlet

Functional description
The volume flow controllers work without an external power supply.
A damper blade with low-friction bearings is adjusted by aerodynamic forces such that a set volume flow rate is maintained within the differential pressure range.
The aerodynamic forces of the airflow create a closing torque on the damper blade.
The bellows extends and increases this force while at the same time acting as an oscillation damper.
The closing force is countered by a leaf spring. As the differential pressure changes, the leaf spring adjusts the position of the damper blade such that the volume flow rate is maintained almost exactly.

Efficient commissioning
The volume flow rate setpoint value can be set quickly and easily using the pointer on the external scale; no measurements are required.
The advantage over flow adjustment dampers is that there is no need for repeat measurements or adjustments by an air conditioning engineer. Should the system pressure change, e.g. by opening or closing of duct sections, the flow rates in the entire system will also change if flow adjustment dampers are used; however, this is not the case with mechanical self-powered volume flow controllers A mechanical self-powered controller reacts immediately and adjusts the damper blade such that the set constant volume flow rate is maintained.

Nominal sizes	80 – 250 mm
Volume flow rate range	6 – 370 l/s or 22 – 1332 m³/h
Volume flow rate control range	Approx. 10 – 100 % of the nominal volume flow rate
Volume flow rate accuracy	Approx. ± 10 % of the nominal volume flow rate
Minimum differential pressure	30 Pa
Maximum differential pressure	500 Pa
Operating temperature	10 to 50 °C

This specification text describes the general properties of the product. Texts for variants can be generated with our Easy Product Finder design program.

Circular volume flow controllers for constant and variable air volume systems with low airflow velocities, mechanical selfpowered, without external power supply, suitable for supply or

extract air, available in 6 nominal sizes.

Ready-to-commission unit consists of the casing containing a damper blade with low-friction bearings, bellows, leaf spring, and a rotary knob to set the volume flow rate setpoint.

Differential pressure: 30 – 500 Pa

Volume flow rate: max. 10 : 1

Spigot with lip seal, for circular connecting ducts to EN 1506 or EN 13180.

Casing air leakage to EN 1751, class C.

Special characteristics

The volume flow rate can be set using an external scale; no tools required
Simple retrofitting of an actuator
Correct operation even under unfavourable upstream or downstream conditions (1.5 D straight section required upstream)
Any installation orientation
Aerodynamic functional testing of each unit on a special test rig before shipping

Materials and surfaces

Casing made of galvanised sheet steel
Damper blade and other parts made of high-quality plastic, to UL 94, V1; to DIN 4102, fire rating class B2
Leaf spring made of stainless steel
Polyurethane bellows

Technical data

Nominal sizes: 80 to 250 mm
Volume flow rate range: 6 – 370 l/s or 22 – 1332 m³/h
Volume flow rate control range: approx. 10 – 100 % of the nominal volume flow rate
Volume flow rate accuracy: approx. ± 10 % of the nominal volume flow rate
Minimum differential pressure: 30 Pa
Maximum differential pressure: 500 Pa

Sizing data

qv [m³/h]
Δpst [Pa]

Air-regenerated noise

LPA [dB(A)]

Case-radiated noise

LPA [dB(A)]

VFC	/	100	/	E03
\|		\|		\|
1		2		3

1 Type
VFC Volume flow controller

2 Nominal size [mm]
80, 100, 125, 160, 200, 250

3 Actuator
No entry: manual adjustment
E01 3-point (min/max) actuator 24 V AC/DC with potentiometer adjustment
E02 3-point (min/max) actuator 230 V AC/DC with potentiometer adjustment
E03 variable actuator 24 V AC/DC with potentiometer adjustment
M01 3-point (min/max) actuator 24 V AC/DC with mechanical stops
M02 3-point (min/max) actuator 230 V AC/DC with mechanical stops

Order example: VFC/100/E03

Type	VFC
Nominal size [mm]	100
Actuator	24 V AC/DC, modulating 0 – 10 V DC, potentiometer

Downloads

product information

brochures

VFC

11 MB pdf

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