Helios Fans RDD 355/4

The Helios RDD 355/4 is a powerful centrifugal roof fan designed for horizontal air discharge, offering high performance and durability in demanding ventilation systems. Engineered for energy efficiency, it features an optimized aluminum casing and a high-performance radial impeller.

The fan’s housing is made from corrosion-resistant, seawater-grade aluminum and includes an integrated safety guard. The motor support and base plate, equipped with an aerodynamic inlet cone, are manufactured from galvanized steel. The base plate also includes threaded bolts, allowing easy attachment of intake-side accessories, and follows the DIN 24155 hole pattern (page 3). For safety, a bird guard compliant with DIN EN ISO 13857 is fitted as standard on the outlet side.

At its core, the RDD 355/4 utilizes a backward-curved centrifugal impeller made from durable polymers, dynamically balanced according to DIN ISO 1940 – 1 to ensure quiet and vibration-free operation.

This unit is driven by a totally enclosed three-phase external rotor motor, designed for continuous operation and protected to IP54 standards. The motor is ball-bearing mounted, equipped with impregnated windings, and is both maintenance-free and radio interference suppressed.

Ideal for industrial and commercial rooftop ventilation systems, the RDD 355/4 delivers reliable and efficient airflow performance.