STDL250 1EC R Twinflow Centrifugal Box Fan Single Phase EC 250mm

The Elta STDL250-1EC-R is a Twinflow duty/standby centrifugal box fan for 250mm duct systems, with rectangular spigots sized 254 x 254mm. 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 1210 m³/h free air, about 1066 m³/h at 100 Pa, and still delivers 392 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 1210 m³/h Speed Controllable What it is best used forDuty/standby extract on 250mm ducting for larger toilet blocks, school and college washroom cores, library and classroom extract, office floors and hotel risers. It gives 1210 m³/h free air, about 1066 m³/h at 100 Pa and still 392 m³/h at 500 Pa, so it copes with filters, silencers and longer runs.Being a twin unit in a 40 kg acoustically lined case, it needs more ceiling void than a single fan. Where a short outage is acceptable, a single fan is the smaller and cheaper choice. 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 SSDL250-1EC-R Singleflow moves more air in the same duct size (1307 m³/h free air against 1210 m³/h here, and 428 m³/h at 500 Pa against 392 m³/h), but when its motor fails the extract stops until someone replaces it. The STDL250-1EC-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 ventilation design; choose the Singleflow where a short outage is acceptable.This model has rectangular spigots (254 x 254mm). If your ductwork is round, the Elta STDL250-1EC is the same fan with 250mm circular spigots. For less air, the Elta STDL200-1EC-R gives 1019 m³/h free air. For more, the Elta STDL315-1EC-R gives 2207 m³/h.Installation notes Mount the fan horizontally only. Elta show it fixed directly to circular or rectangular duct, inverted, on AV mounts or hung from drop rods, and leave access for maintenance. Bring the 220 to 240V single phase, 50/60Hz supply to the terminals of the fitted auto changeover panel and provide a local means of isolation. Wiring diagram 152-717 applies. Set the maximum speed on the 149-CD-POT commissioning board. For external control from a potentiometer, the 149-POT-10-MI or a 0-10V BMS signal, remove the jumper and connect to terminals ST1; the board setting then caps the top speed. The panel's test jumper shortens the duty share switching time from 12 hours to 1 minute, so you can prove the changeover works at commissioning. Disconnect the EC fans before any insulation resistance testing. The electronics can be damaged and this is not covered by warranty. You'll also need Elta EC Electronic Controller 149-POT-10-MI for remote manual speed control. Elta AV mounts 062-SEL03 available to order, ask us. What's in the box Twin fan STDL unit Auto changeover panel 149-ACO1/EDV, fitted 149-CD-POT commissioning control, fitted Browse more commercial box fans, twin fans or Elta fans, or call us for help choosing the right fan.Specifications Model STDL250-1EC-R Type Twin fan duty/standby centrifugal box fan, EC Duct connection 254 x 254mm rectangular spigots Max airflow 1210 m³/h Static pressure 500 Pa Motor Twin EC, 1 phase 220-240V 50/60Hz, 2490 rpm Power 0.165 kW input at best efficiency, 1.15 A peak Noise 53 dB(A) inlet, 58 dB(A) outlet, 35 dB(A) breakout at 3m IP rating IP44 motors Warranty 1 Year Manufacturer Changeover control Auto changeover panel 149-ACO1/EDV, fitted Speed control 149-CD-POT commissioning potentiometer, 0-10V external input Airflow at 100 Pa 1066 m³/h Airflow at 200 Pa 896 m³/h Overall efficiency 43.4% at best efficiency point Casing 1.2mm galvanised mild steel, acoustically lined Mounting Horizontal only Ambient temperature -20°C to +60°C, up to 90% RH Weight 40 kg Manuals & Guides Elta Twinflow STDL Datasheet Elta Twinflow STDL Installation Manual