2424AT

System Sensor 2412AT, 2424AT and 2424AIT photoelectronic smoke detectors are designed to provide open area protection and to be used with UL-listed 4-wire control panels. The 2412AT operates at 12 VDC and the 2424AT and 2424AIT operate at 24 VDC. The sensor in this detector operates on the light scattering principle and features a unique photo-optic sensing chamber that provides good smoke entry while minimizing the effects of ambient light. These detectors also provide restorable 135°F fixed-temperature heat detection.

The 2412AT and 2424AT heat detection unit is integrated with the photoelectronic sensor while the 2424AIT's heat detection unit is isolated from the photoelectronic smoke sensor and can be monitored separately. In addition, a piezoelectric horn in each detector produces an interrupted, 85 dBA minimum tone when the individual detector alarms or when the supply voltage polarity is reversed. An LED on each detector lights to provide a local alarm indication and will remain on when the supply polarity is reversed. A screw terminal is provided for a remote LED annunciator optional accessory (RA400Z). These detectors are listed to UL268 and are latching type system detectors.

The alarm can be reset only by momentary power interruption. For testing, these detectors 2424AT have a test switch or may be tested by inserting a calibrated test card in a test slot after removing the detector's cover. Each detector contains one Form A (SPST-NO) contact for connection to an alarm-initiating circuit. Supervision of the detector power is accomplished by installing a Power Supervisory End-of-Line Relay Module (A77-716) at the end of the detector power loop. When power is applied to and through the detectors, the EOL Power Supervisory Module is energized.

2424AT's relay contacts close and provide a closed series circuit in the control panel's alarm-initiating loop. A power failure or break in the detector power loop deenergizes the EOL Module. The relay contacts open and trigger a trouble signal at the control panel.