Elta STDL400-1EC-R Twinflow Centrifugal Box Fan Single Phase EC - 400mm (rectangular spigots)

The Elta STDL400-1EC-R is a Twinflow duty/standby centrifugal box fan for 400mm duct systems, with rectangular spigots sized 448 x 598mm. Two backward curved fans sit side by side in one acoustically lined case: one runs, the other waits on standby. At full speed it moves up to 4392 m³/h free air, about 3996 m³/h at 100 Pa, and still delivers 2084 m³/h against 500 Pa.Each fan has an IP44 EC external rotor motor (220 to 240V single phase, 50/60Hz) with sealed for life bearings, and the case is 1.2mm galvanised mild steel. An auto changeover panel (149-ACO1/EDV) is fitted as standard, switching to the standby fan if the duty fan fails and sharing run hours between the two. Speed is set by the built in commissioning potentiometer or a 0-10V signal, and Elta give a 12 month (1 year) manufacturer warranty. 1 Phase EC Motor Up to 4392 m³/h Speed Controllable What it is best used forHigh volume duty/standby extract on a single phase supply: factory and workshop general ventilation, warehousing, industrial units, large commercial kitchens (general ventilation, not canopy), college halls and sports halls. It moves 4392 m³/h free air and about 3568 m³/h against 200 Pa.It weighs 112 kg, so plan drop rods or a supporting frame with the AV mounts. The 4.20 A peak current is high for a single phase circuit, so check the supply. Not for corrosive, explosive or above +60°C air.Why choose this over alternativesThe point of a twin fan is resilience. A single fan such as the Elta SSDL400-1EC-R Singleflow moves more air in the same duct size (4414 m³/h free air against 4392 m³/h here, and 2390 m³/h at 500 Pa against 2084 m³/h), but when its motor fails the extract stops until someone replaces it. The STDL400-1EC-R keeps running on its standby fan, the panel gives normally open fail and run contacts for a BMS or alarm, and the duty share means neither motor does all the hours. Choose it for windowless toilets, risers and any system where a dead fan means a complaint or a breach of the v