The DH400 duct detector samples air currents passing through a duct and gives dependable performance for shutdown of fans, blowers, and air conditioning systems, preventing the spread of toxic smoke and fire gases through the protected area. The twist-in, twist-out heads allow for quick and easy cleaning or application changes without removing the duct housing. Since duct detectors are often mounted in inaccessible areas, the RTS-451 remote test station can be mounted at a convenient location and allows the detector head to be tested without the need for access to the duct detector. Sampling tubes are available separately in four different lengths to suit ducts from 0.3m to 3.6m wide. Some control panels require a resistor to be fitted in series with the detector. For this reason, a series 750 series resistor is mounted in the DH400 (see wiring diagram). To activate this resistor, simply cut jumper J1 on the DH400 PC board with a pair of wire cutters (see illustration overleaf).

• 12 / 24V operation • Ionisation and Photodetector versions available • Air velocity rating from 2.5 m/s to 20 m/s • Remote test station and remote annunciator • Clear polycarbonate cover for easy visual inspection of sampling tube filters • Suits round or rectangular ducts 0.3m - 3.6m wide • Remote LED output

mechanical Length 367 mm Width 127 mm Depth 102 mm Weight 1.8 Kg Duct air velocity 2.5 to 20 m/s Relative Humidity 10% to 93% (non-condensing) Temperature Range -10°C to +60°C