D400-04-00
1
I56-288-05
2412AT, 2424AT, and 2424AIT
Direct Wire Photoelectronic with
Fixed Heat Smoke Detectors
INSTALLATION AND MAINTENANCE INSTRUCTIONS
A Division of Pittway
3825 Ohio Avenue, St. Charles, Illinois 60174
1-800-SENSOR2, FAX: 630-377-6495
Before Installing
Please thoroughly read the System Sensor manual I56-407-
XX,
Guide for Proper Use of System Smoke Detectors
, which
provides detailed information on detector spacing,
placement, zoning, wiring, and special applications. Copies
of this manual are available at no charge from System
Sensor. (For installations in Canada refer to CAN\ULC-
S524,
Standard for the Installation of Fire Alarm Systems
and CEC Part 1, Sec. 32.)
General Description
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
Specifications
Diameter:
5.5 inches (14 cm)
Height, with Thermal:
3.19 inches (8.1 cm)
Weight:
0.7 lb. (310 g)
Operating Temperature:
0
°
to 38
°
C (32
°
to 100
°
F)
Operating Humidity:
10% to 95% Relative Humidity Non-condensing
Visual Indicator:
Solid State LED
Locking Alarm:
Reset by momentary power interruption
Audible Signal:
85dBA minimum interrupted tone when individual unit is in alarm or when the
supply voltage is reversed.
Electrical Ratings:
2412AT
2424AT or 2424AIT
Operating Voltage:
12VDC
24VDC
Full-wave, Unfiltered
Full-wave, Unfiltered
Current
Standby:
120
µ
A Max.
120
µ
A Max.
Alarm:
51mA
43mA
(Add 7mA Maximum with RA400Z Remote Annunciator LED)
Reversed Supply:
8mA
15mA
Start-up Time:
36 seconds maximum
Relay Characteristics:
One Form A (SPST-NO) for alarm initiation 1.25A at 30 VAC/DC
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 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. Its 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 de-
energizes the EOL Module. The relay contacts open and
trigger a trouble signal at the control panel.
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