Further information for Helios Ventilatoren RVS 280 - Helios automatic pipe closure flap spring 2593
To prevent cold air from entering when the fan is not running. Function through fan operation. Cylindrical sheet steel housing with flanges on both sides. Can be screwed directly onto the fan base plate or flange. Hole pattern in accordance with DIN 24155. Low-noise operation. Spring mechanism outside the air flow, locking force adjustable.