CONTROL MODULES

TM 10-6665-297-13&P 1-2 GAS DETECTOR UNITS (continued) 1-2.3 Detector Models (continued) (3) Model 23-4017: remote mounting detector housing with integral air aspirator for continuous sample drawing. Sample gas is transported to the sensor through a length of tubing from enclosed areas, tanks, and vessels not otherwise readily accessible; from high-velocity gas streams; from areas containing more dirt or moisture than desirable for diffusion sampling; from nitrogen-inerted atmospheres where air blending is required; from elevated-temperature areas (200° F or higher); or any situation where sample conditioning is required. (For example: If flash point of combustible material is greater than 70° F, sample line and detector must be heated to above flash point.) Approved for use in N.E.C. Class I, Division 1, Groups A, B, C, and D hazardous areas. (4) Model 800-086: explosion-proof, weatherproof detector housing; diffusion sampling (Figure 1-3). Approved for use in N.E.C. Class I, Division 1, Groups B, C, and D hazardous areas. (5) Model 23-7317: explosion-proof, weatherproof housing; diffusion sampling; high-humidity shield to protect sensor element from heavy moisture content in the air (Figure 1-3). Approved for use in N.E.C. Class I, Division 1, Groups B, C, and D hazardous areas. Catalytic sensor elements in all models have flame arrestors caps to prevent ignition of combustible gases in the air. Each detector assembly has a 5-layer mesh monel screen enclosing the plug-in sensing element, providing redundant flame-arresting protection. 1-3 CONTROL MODULES All CD800/830 and 802/832 control modules contain power regulating and signal processing circuitry, percent L. E.L. indicating meter, indicator lights to signal gas conditions and system operating modes, circuit adjusters, and relays in small, compact units. CD800/830 series and CD802/832 series control modules differ in that each CD800/830 control module ordinarily monitors a single detector (or if two, the signals from both are summed as if for one), whereas each CD802/832 control module incorporates two discrete channels for the independent monitoring of signals from two detectors. The CD802/832 control module features a channel selector control that can be set either to AUTO (automatic mode), in which meter and signal lights respond to the channel receiving the strongest signals from the detectors, or to either of two channel positions, in which meter and signal lights respond to the channel selected. Alarm, warning, and failure circuitry and indicators remain active for both channels, regardless of the channel-selector control position. 23-9617 7-1-76 1-6