RMH - Mixed Flow Roof Fans



Specially designed for use when medium pressure characteristics are required, the Vent-Axia Mixed Flow roof range is delivered on-site fully assembled and ready for installation. To meet COSHH requirements, a service isolator is fitted and pre-wired as standard. Equally suitable for flat or inclined roofs, the range is suitable for kerb or purlin box mounting and boasts a wide range of accessories to suit many different industrial applications. There are five sizes available with duties ranging from 0.606m³/s to 3.63m³/s (2182m³/h to 13068m³/h) with pressure development available up to 600 Pa.

The mounting plate is moulded with a fixed integral bellmouth to ensure optimum efficiency and precise alignment. The weather-cowl is also moulded to produce a smooth, internal surface and a tough, stable UV resistant finish. Colour: BS 10A07. Alternative colours available on request.

Vent-Axia Mixed Flow Roof fans are designed for either kerb or inclined fixing (maximum angle 30°).


The Mixed Flow roof range features a proven external rotor motor and backward curved mixed flow aluminium impeller assembly (355 Ø in polyamide) selected for performance and non-overloading characteristics. The assembly is dynamically balanced to VDI 2060. The motors in this range are rated IP44 according to BS EN 60529. Ball bearings are greased for life and are designed to run at any angle. Insulation is Class 'B' (from -30°C to +40°C). Manufacture is controlled to BS EN ISO 9001 standards.


Single phase 220-240V 50 Hz. Capacitor start and run. Three phase 380-415V 50Hz. A service isolator switch is provided for local isolation and the enclosure is protected to IP65 according to BS EN 60529. All motors are fitted with Standard Thermal Overload Protection (S.T.O.P.), which for three phase fans should be wired into all controller circuits and into starter contactors. Most models are available with 4 and 6 pole motors.


Fan Size a b c d Weight Kg
335/400 800 780 480 83 24/27
450 950 930 575 103 45
500/560 1230 1055 630 103 48/64



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