Sentinel D-Box Twin Fan 500mm

  • Duct Sizes 100 - 500mm
  • Airflow 0.001 to 1.3 m3/s
  • Pressure up to 650Pa
  • Sentinel demand ventilation fan with lockable isolator
  • Latest energy saving EC/DC motors
  • Alunzinc construction suitable for internal or external mounting
  • Manufactured controlled to BS EN ISO 9001
  • Performance tested to BS848 Part 1 & 2

Product Overview

Ventilation Type
Commercial Ventilation
Product Range
Sentinel D-Box Twin
IP Rating

The Sentinel twin in-line duct fans are as supplied from Vent-Axia Ltd. Manufactured from Aluzinc, Sentinel fan units are internally treated with an ‘O’ class rated, BS476 part 6 & 7, acoustic foam which offers the benefits of high sound absorption, good thermal insulation properties in addition to self  extinguishing properties and resistant to ignition.

Weatherproof external units incorporate an additional controller shroud.

The housing is designed to be as compact as possible for concealed false ceiling applications and Sentinel casings are specially designed to allow the unit to be mounted via its unique mounting bracket, ensuring a quick and easy solution to installation.

The unit is suitable for ceiling or floor mounting, non-return dampers can be easily rotated on site to suit.


All Sentinel units feature a low energy, Class 1, EC/DC external rotor motor and backward curved impeller assembly specifically chosen for performance and non-overloading characteristics. The assembly is dynamically balanced to DIN ISO 1940 Grade 6.3, duct size 500mm rated IP54, all other sizes, IP44 according to BS EN 60529. Ball bearings are greased for life. Insulation is Class ‘B’ (from -25°C to +60°C).

All models incorporate internal electronic overload protection and soft start function.


Every Sentinel unit is fitted with a purpose designed common PCB controller incorporating a 16-character backlit alphanumerical x 2 line display with 4 button membrane keypad for fan status & commissioning set up. The enclosure is fitted with a 4-pole 10A isolator that is suitable for fitting a locking device to prevent accidental operation.

The twin unit controller features automatic 6hr duty/share and run/ standby in the event of motor failure.

Motors are single phase 230V +/- 10% / 50/60Hz / 1ph (size 100- 400mm) or 400V +/- 10% / 50/60Hz / 3ph (size 500mm), (4 wire systems only).

24V DC power is provided from the controller for powering the matched range of Sentinel switches and sensors.


Extensively tested to BS848 parts 1 & 2. Published dB(A) figures are free field sound pressure levels at 3m with spherical propagation at reference level of 2x10-5 Pa. The inlet/outlet sound power level spectra figures are dB with a reference of 10–12 Watts.

Weatherproof Typical Ordering Designation

Ordering codes are similar to existing units with Suffix…. /WP which enotes Weatherproof finish.

Example: SENT100T/CP/WP


For duct accessories see Ducting and Fitting Section.

Product Downloads

Installation Instructions

Catalogue Pages

3D Revit Files


Duct Air Heater 21kW 500mm Three Phase
  • Supply and extract fan outputs
  • Combined temperature and airflow sensor
  • Run on timer
  • Solid state switching - no mechanical switching breakdown
  • Indicators for control status
  • High temperature limit and manual reset
  • Separate supply and extract fan outputs for heaters
    over 150mm diameter
  • Setting range: +6°C to +30°C
  • Two internal range limit/locking rings are included to allow setting within a limited temperature range or locking at a fixed t/o point
  • IP20 rated
  • Sealed sensing mechanism
  • Snap-action, single pole, changeover contacts
  • Mounting direct on surface only
  • Electrical connection to screw type terminals with rear or side cable entry
  • Contact rating: 1.5 amp (inductive)
  • 16 amps (resistive)
  • Max Voltage 250V
7 Day TimeSwitch
  • Analogue clock display and integral time switches for ease of setting
  • Manual override
  • Removable clear plastic cover protects TimeSwitch face
  • Volt free changeover contacts
  • Time base: 7 days
  • Shortest switching time: 2 hours
  • Maximum load: 16amp resistive (8amp inductive)
  • Ambient operating temperature range -20°C to +85°C
  • Ambient operating temperature range -20°C to +85°C
  • Ambient operating temperature range -20°C to +85°C