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Click to View: General Features Description Maintenance & Installation

GENERAL
The Faraday 8930/31 Air Duct Detector Housings are designed to be used with the Faraday 8900 series ionization or photoelectric detectors. Designed for installation directly to heating, ventilating, and air conditioning duct systems, they comply with National Fire Protection Association Standard No. 90A. When equipped with ionization or photoelectric detectors, these units will signal the presence of hazardous quantities of products of combustion or smoke being carried through the duct system. Air duct detectors are not intended to be substituted for open area detection.

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FEATURES

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DESCRIPTION
The Faraday 8930/31 Air Duct Housing is uniquely designed to use the highly sensitive yet stable 8904, 8905 Ion and 8940 Photoelectric detectors.

The detector unit employs a cross-sectional sampling principle of operation. Inlet sampling tubes are available in four lengths (see ordering information). Outlet sampling tubes are one common length. A continuous cross-sectional sample of air moving through the duct is taken. This averages the effects of laminar flow, stratification or skin effect phenomena occurring in the duct that could prevent combustion product or smoke (especially in large ducts) from reaching a spot type detector.

In addition, the unique design of the Faraday sampling chamber insures uniform sensitivity in air velocities, ranging from a low of 500 feet per minute to as high as 400 feet per minute.

The inlet sample tube length is determined by the width of the air duct being protected. The inlet tube nearest to but greater than the duct width should be used. The inlet tube can then be trimmed at the job site to the exact width of the duct. The outlet sampling tube for all ducts, irrespective of width, has fixed a length of approximately 3 inches (7.5 cm) and is supplied with the Duct housing.

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MAINTENANCE AND INSTALLATION

Maintenance of the detector is easily accomplished by the removal of the Series 8930/31 Duct Housing sampling chamber cover. The detector, which plugs into the housing, is easily removed for cleaning by a trained technician.

All that is necessary for the installation of the air duct detector is the cutting of three small holes for the sampling tube installation (template included) and the drilling of four holes for mounting the air duct housing. The unit is then easily mounted in place and connections made to the existing wires or terminals if optional accessories are utilized.

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