AIRBOX SLIM 520 – insulated box for AFL Constant Flow EC fans

AIRBOX SLIM 520

Aerodynamically optimized insulated casing for AFL Constant Flow fan installation.

AIRBOX SLIM 520 is not an ordinary fan enclosure. It is a sophisticated mounting and insulating box that has been developed, tested and optimized to achieve the lowest possible power consumption while maintaining high airflow.

The product is designed for the installation of a compatible AFL Constant Flow radial fan. The fan has integrated control electronics and its own regulation system, which automatically adjusts its performance to maintain the required air volume flow.

Therefore, to ensure the Constant Flow function, it is not necessary to install external pressure sensors, pressure transmitters, pressure gauges or a separate pressure difference measurement system.

The fan, electrical connection and higher-level control are not part of the AIRBOX casing itself.

Just install a compatible AFL Constant Flow fan, connect the ducts and 0-10 V control. The AIRBOX is ready to create a professional ventilation unit in minutes.

AIRBOX SLIM 520 is supplied without a fan. Photos show an example of AFL Constant Flow fan installation.

Why choose AIRBOX SLIM 520?

Tested design with minimal consumption

During the development of AIRBOX SLIM 520, we tested various lengths, widths, depths and internal shapes of the box. We tried rounded corners inside, a dome-shaped cover and tilting the fan inside the casing.

However, measurement results showed that these solutions led to higher energy consumption. The best result was achieved precisely with the AIRBOX SLIM 520 design with spigots placed diagonally in a cross.

At approximately the same airflow of approx. 517.1 m³/h, a consumption of approximately 120 W was measured for the variant with spigots on the same axis. For the final version of AIRBOX SLIM 520, the consumption was only 82.7 W.

Why aren't the spigots on the same axis?

In a low-profile box, a direct arrangement of the inlet and outlet on the same axis would cause less favorable airflow inside the casing. The air stream would concentrate in one part of the space and the fan would operate under a higher load.

Therefore, in the AIRBOX SLIM 520, the spigots are placed diagonally in a cross. The air is better distributed inside the box, the flow is smoother and the AFL Constant Flow fan does not need to unnecessarily increase performance to overcome pressure losses.

The result is significantly lower electrical power consumption while maintaining high airflow.

Measured consumption values

Measurement conditions:

• measurement performed with installed AFL Constant Flow fan,
• volume flow measured with TESTO 405 probe,
• TESTO 405 measuring probe placed in a 2 m long exhaust duct,
• duct diameter 200 mm,
• fan output to free space.

AIRBOX SLIM 520 dimensional drawing

A dimensional drawing of the AIRBOX SLIM 520 is available for dimension checking and installation design.

The drawing contains basic external dimensions, position of connection spigots and mounting elements.

View drawing in higher resolution

Dimensions and technical parameters

Insulation against condensation and noise

The 10 mm thick synthetic rubber internal insulation reduces the risk of condensation on the casing surface while helping to dampen fan noise.

AIRBOX SLIM 520 is therefore also suitable for installation in residential buildings, technical rooms or suspended ceilings.

Polypropylene construction

AIRBOX SLIM 520, like our RECUBOX® units, is made of high-quality polypropylene.

• moisture resistance,
• no corrosion,
• low weight,
• long lifespan,
• easy maintenance.

The connection spigots are equipped with double-lip seals for a firm and tight connection of the ventilation ducts.

Service access to the fan is via a door.

Simple mounting and flexible connection

AIRBOX SLIM 520 is designed for the fastest possible installation into the ventilation system.

The casing is equipped with 4 mounting brackets with 12 mm diameter holes, which allow for simple and safe attachment to the ceiling, wall or supporting structure.

Thanks to the service door, the fan is easily accessible for installation, inspection and possible replacement.

There are six spigot diameters to choose from:

• Ø 125 mm
• Ø 150 mm
• Ø 160 mm
• Ø 200 mm
• Ø 250 mm – enlarged design
• Ø 315 mm – enlarged design

Constant Flow as the basis for balanced heat recovery

The greatest advantage of AFL Constant Flow fans is the ability to automatically maintain the set air volume flow even with changes in pressure losses in the ventilation system.

The fans have their own built-in control electronics and integrated regulation system. The fan electronics continuously evaluate its operating status and automatically adjust the speed to maintain the required air volume flow.

Therefore, for the Constant Flow function itself, it is not necessary to install external pressure sensors, pressure transmitters, pressure gauges or a separate pressure difference measurement system.

The required fan performance is set via a 0-10 V control signal. The fan then automatically responds to, for example:

• gradual clogging of filters,
• changes in ventilation duct resistance,
• different lengths of supply and exhaust routes,
• changes in the position of regulation or distribution elements,
• other changes in system pressure losses.

If you connect two AFL Constant Flow fans to the same 0-10 V control signal and connect them to our RECUBOX® units, you get a simple basis for a modern balanced heat recovery system with very low electrical power consumption.

• one fan provides the air supply,
• the other fan provides the air exhaust,
• each fan automatically responds to pressure losses in its branch,
• both fans can be controlled by a common 0-10 V control signal,
• there is no need to add an external pressure measurement system.

Such a solution is ideal for RECUBOX® modular heat recovery sets, smart homes, Loxone, Home Assistant and other building management systems.

12-year warranty on casing tightness and construction

We provide an above-standard 12-year warranty on the AIRBOX casing.

AIRBOX is made of high-quality polypropylene and joined using hot gas welding technology. The result is homogeneous, strong and long-term stable joints with no risk of corrosion.

Unlike sheet metal structures, there is no risk of corrosion, and unlike glued structures, the joints do not age due to moisture or temperature changes.

Thanks to its simple design with no moving parts, the AIRBOX is designed for long-term and trouble-free operation. We therefore provide a 12-year warranty on the tightness and mechanical integrity of the polypropylene casing.

What AIRBOX SLIM 520 is and isn't

AIRBOX SLIM 520 is a mounting and insulating casing for the installation of a compatible AFL Constant Flow fan.

The AIRBOX itself does not contain a fan, motor, electrical components or control electronics. It is a passive mechanical element designed for integration into a ventilation system.

The selection of the fan, its mounting, electrical connection and commissioning of the resulting assembly are carried out by the customer or a professional installation company.

RECUBOX® AIRBOX SLIM 520 is designed as a mounting and insulating casing for the installation of a compatible AFL Constant Flow fan. The fan itself, electrical connection and higher-level control are not part of the AIRBOX casing.