TROX GmbH

Product Overview

The Type VFL volume flow limiter is used for balancing volume flow rates in ventilation systems. It prevents the volume flow rate from exceeding a setpoint and maintains the flow rate even if pressure fluctuates.

Fig. 1: Volume flow limiter Type VFL depicts the device with the following components: 1. Damper blade, 2. Bellows inlet, 3. Bellows, 4. Crossbar, 5. Volume flow rate scale.

Correct Use

The VFL is suitable for balancing volume flow rates in ventilation systems. It is not recommended for extract air systems in commercial kitchens unless the air is thoroughly cleaned according to VDI 2052. Installation in humid, explosive, dust-laden, or aggressive air environments requires prior assessment based on site conditions.

Important Notes

This manual provides essential information for operating and service personnel to correctly install and safely use the product. It is crucial to read and understand this manual before commencing any work. Compliance with safety notes, instructions, and local health and safety regulations is mandatory.

TROX Technical Service

For prompt service, please have the following information ready:

• Product name
• TROX order number
• Delivery date
• Brief description of the fault

Contact TROX Technical Service via:

• Online: www.troxtechnik.com
• Phone: +49 2845 202-400

Qualified Staff

Personnel performing installation and maintenance must be HVAC technicians, possessing sufficient professional or technical training, knowledge, and experience to carry out duties responsibly and in compliance with relevant guidelines and regulations.

Transport and Storage

Follow all guidelines, safety regulations, and instructions. HVAC technicians are responsible for professional work completion.

Personal Protective Equipment (PPE): Must be worn to minimize health and safety hazards. The appropriate PPE should be used for the duration of the job.

• Industrial safety helmet: Protects the head from falling objects, suspended loads, and impacts.
• Protective gloves: Protect hands from friction, abrasions, punctures, deep cuts, and hot surfaces.
• Safety shoes: Protect feet from crushing, falling parts, and slipping.

Limitation of Liability

The information in this manual is based on applicable standards, guidelines, current technology, and extensive experience. TROX GmbH does not accept liability for damages resulting from:

• ✔️ Non-compliance with this manual
• ❌ Incorrect use
• ❌ Operation or handling by untrained individuals
• ❌ Unauthorised modifications

The actual scope of delivery may vary for special constructions, additional options, or due to technical changes.

Delivery Check

Upon delivery, carefully unpack and check the unit for transport damage and completeness. Contact the shipping company and supplier immediately for any issues. Repack the product to protect it from dust and contamination.

Fixing and Installation Material

Fixing and installation material is not included in the supply package unless otherwise stated and must be provided by the installer. It must be suitable for the specific installation situation.

Transport on Site

⚠️ CAUTION! Danger of injury from sharp edges, sharp corners and thin sheet metal parts! Sharp edges, corners, and sheet metal may cause cuts or grazes. Always be careful during work and wear protective gloves, safety shoes, and a hard hat.

Please note:

• Be careful when unloading or moving the product, paying attention to packaging symbols and information.
• Transport the product in its original packaging to the installation location if possible.
• Use only lifting and transport gear designed for the required load.
• Always secure the load against tipping and falling.
• Do not move bulky items alone; seek assistance to prevent injuries and damage.

Storage

Please note:

• Store the product only in its original packaging.
• Protect the product from weather effects, humidity, dust, and contamination.
• Storage temperature: -10 °C to 50 °C.
• Relative humidity: 95% max., no condensation.

Packaging

Dispose of packaging material properly.

Technical Data

General Technical Data

Dimensions and Weight

Fig. 2: VFL shows the dimensions of the VFL unit, indicating the overall diameter (ØD) and length (L).

Product-Specific Data for VFL

Installation

Installation Orientation

• The airflow direction is critical.
• The installation orientation is not critical.

Upstream Conditions

The volume flow rate accuracy applies to a straight upstream duct section. Bends, junctions, or duct constrictions/expansions can cause turbulence affecting measurement. Observe requirements for straight duct sections upstream of the control unit. Duct connections must comply with EN 1505.

Fig. 3: Bend illustrates a bend with a curvature radius of at least 1D. Without an additional straight duct section upstream, it has a negligible effect on accuracy.

Fig. 4: Junction illustrates a junction. A junction causes strong turbulence. Stated volume flow rate accuracy is achieved with a straight duct section of at least 1.5D upstream. Without this, control may be unstable, even with a perforated plate.

Note: If installing a shut-off damper upstream of the CAV controller, ensure its blade axis is rotated 90° relative to the controller's blade axis.

Setting the Flow Rate Setpoint

Tool: Torx T9 screwdriver (not included).

Fig. 5: Setting the flow rate setpoint shows a hand using a Torx screwdriver to adjust the volume flow rate setpoint on the scale indicated by a sticker.

1. Use the Torx screwdriver to set the required volume flow rate setpoint on the scale (sticker).

Fig. 6: Covering the slotted hole shows a hand covering a slotted hole with a clear sticker.

2. Cover the slotted hole with the provided clear sticker to improve acoustic properties.

Installing the CAV Controller

Personnel: HVAC technician.

Protective equipment: Industrial safety helmet, Protective gloves, Safety shoes.

Before installation, take precautions to protect air distribution components from contamination (VDI 6022). Cover the product or take other measures if contamination cannot be avoided. Ensure the product cannot be started during these procedures. All components must be clean before installation. Clean them thoroughly if necessary. Protect openings from dust and moisture if the installation is interrupted.

For installation please note:

• The installed product must be accessible for maintenance and service.
• Handle the controller with care to avoid accidental damage.
• Lift the controller only by its entire casing.
• Do not lift the controller by holding the damper blade, rotary knob, or actuator.

Maintenance and Cleaning

Maintenance

The system owner is responsible for setting up a maintenance schedule based on operating conditions (contamination, operating time, etc.).

Important: Do not lubricate the bearings of the damper blade.

Maintenance jobs to be carried out regularly:

• Visually check the controller for contamination, damage, and corrosion. Remove contamination. Replace the controller if damaged or corroded.
• Check the fixing of the controller and connected ductwork.

Cleaning

Please note:

• Cleaning intervals as per VDI 6022 standard apply.
• Clean surfaces with a damp cloth.
• Use only common household cleaners; avoid aggressive cleaning agents.
• Do not use cleaning agents containing chlorine.

Fig. 7: Installing VFL illustrates the installation process:

1. Set the flow rate setpoint (refer to 'Setting the flow rate setpoint' on page 6).
2. Insert VFL into the duct. The arrow indicates the correct airflow direction.
3. Push the duct sections together.
4. Use provided stickers to indicate controller positions, writing on them and affixing them to the duct for visibility.