D200-85-00 1 I56-1241-03R
2112/24AITR
Photoelectronic Smoke Detector with
Fixed Heat and Integral Temp-3 Sounder
INSTALLATION AND MAINTENANCE INSTRUCTIONS
3825 Ohio Avenue, St. Charles, Illinois 60174
1-800-SENSOR2, FAX: 630-377-6495
Specifications
Diameter: 5.5 inches (140 mm)
Height (including mounting bracket): 2.05 inches (52 mm)
Weight: 7.5 oz. (210 g)
Operating Temperature Range: 32° to 100°F (0° to 38°C)
Operating Humidity Range: 10% to 93% Relative Humidity, Noncondensing
Latching Alarm: Reset by momentary power interruption
Audible Signal: 85 dBA minimum when in alarm or with supply polarity reversed
Heat Sensor: 135°F Fixed Temperature Electronic Thermistor
Electrical Ratings
System Voltage (nominal): 12 or 24 VDC
Minimum: 10 VDC
Maximum: 35 VDC
Maximum Ripple Voltage: 30% of nom. Voltage (peak to peak)
Standby Current: 50 µA maximum
Alarm Current: 49 mA typical, 60 mA max. at 12V
57 mA typical, 65 mA max. at 24V
Reset Voltage: 0.8 VDC minimum
Reset Time: 1.0 second maximum
Start-up Time: 30 seconds maximum (after 60 sec. reset)
EOL Relay: A77-716B, 12/24 VDC
Note: Relay changes only when the thermal alarm state is reached
Alarm Initiation and Auxiliary Relay: 1A @ 30 VAC
Contact Ratings, Resistive Load: 1A @ 30 VDC
Special Considerations: Due to the built-in temporal pattern, use these detectors only with a non-coded power supply.
Figure 1. Wiring diagram for the 2112/24AITR detector:
A78-2336-16
Before Installing
Please thoroughly read the System Sensor manual I56-407, Guide for
Proper Use of System Smoke Detectors, which provides detailed informa-
tion on detector spacing, placement, zoning, wiring, and special applications. Copies of this manual are available at no charge from System
Sensor.
NOTICE: This manual shall be left with the owner/user of this equipment.
IMPORTANT: This detector must be tested and maintained following
NFPA 72 requirements. The detector should be cleaned at least once a
year.
IMPORTANT: OBSERVE POLARITY
As with all sounder models, polarity must be observed on the power connections.
OPTIONAL CLASS A WIRING
EOL RESISTOR
SPECIFIED BY
PANEL
MANUFACTURER
EOL POWER
SUPERVISION
RELAY (SHOWN
ENERGIZED)
A77-716 12/24V
POWER
TO
DETECTORS
UL LISTED
COMPATIBLE
CONTROL
PANEL
INITIATING
LOOP
+
–
P
W
R
A
U
X
P
W
R
A
U
X
+
+
–
A
A
NC
C
NO
+
+
–
A
A
NC
C
NO
ALARM
CONTACT
ALARM
CONTACT
(OPTIONAL)
RELEASING
DEVICE
NC
COMMON
NO
(OPTIONAL)
RELEASING
DEVICE
NC
COMMON
NO
D200-85-00 2 I56-1241-03R
TAMPER SLOT
(DEPRESS TAB TO
REMOVE DETECTOR)
TAMPER RESISTANT TAB
(CUT OFF SMALL TAB TO
ACTIVATE TAMPER-RESIST
FEATURE)
ALIGNMENT
ARROWS
Figure 3. 2112/24AITR smoke detector mounting bracket:
A78-2333-01
Wiring Installation Guidelines
All wiring must be installed in compliance with the National Electrical
Code, applicable local codes, and any special requirements of the local
authority having jurisdiction. Proper wire gauges should be used. The
conductors used to connect smoke detectors to control panels and accessory devices should be color-coded to reduce the likelihood of wiring
errors. Improper connections can prevent a system from responding properly in the event of a fire.
The screw terminal block accepts 14 – 22 gauge wire. For best system performance, all wiring should be installed in separate grounded conduit. Do
not mix fire system wiring in the same conduit as any other electrical
wiring. Twisted pair may be used to provide additional protection against
electrical interference.
Smoke detectors and alarm system control panels have specifications for
allowable loop resistance. Consult the control panel specifications for the
total loop resistance allowed for the control panel being used before
wiring the detector loops.
Wire connections are made by stripping about 1/4 inch of insulation from
the end of the feed wire, inserting the wire into the appropriate terminal,
and tightening the screw to secure the wire in place.
Installation
Where to Install Smoke Detectors
Warning: As a minimum requirement, smoke detectors must be installed
in accordance with the National Fire Protection Agency (NFPA) Standard
72 which defines the standards for the National Fire Alarm Code (National
Fire Protection Association, Batterymarch Park, MA 02269-9101). In addition, observe all local and national building and electrical codes.
Proper Detector Location:
Figure 1: Recommended smoke detector protection for singlefloor residence with only one sleeping area
Figure 2: Recommended smoke detector protection for singlefloor residence with more than one sleeping area:
NFPA 72, Chapter 2, Section 2-2.1.1.1 states as follows: “Smoke detectors
shall be installed outside of each separate sleeping area in the immediate
vicinity of the bedrooms and on each additional story of the family living
unit, including basements and excluding crawl spaces and unfinished
attics. In new construction, a smoke detector also shall be installed in
each sleeping room.”
The above NFPA standard is a minimum requirement for smoke detector installation. For better protection, we also require the installation
of a smoke detector inside every bedroom in existing construction.
• Install a minimum of two smoke detectors in any household, no
matter how small it is.
• Put a smoke detector in the hallway outside of every separate bedroom area. (See Figure 1.) A minimum of two detectors are required
in homes with two bedroom areas. (See Figure 2.)
BEDROOM
SMOKE DETECTORS FOR
MINIMUM PROTECTION
SMOKE DETECTORS FOR
MORE PROTECTION AND
REQUIRED IN NEW CONSTRUCTION
BEDROOM
BEDROOM
LIVING ROOM
DINING
ROOM
KITCHENFAMILY ROOM
DINING ROOM KITCHEN BEDROOM BEDROOM
BEDROOMLIVING ROOM
SMOKE DETECTORS FOR MINIMUM PROTECTION
SMOKE DETECTORS FOR MORE PROTECTION AND
REQUIRED IN NEW CONSTRUCTION
General Description
Model 2112/24AITR is a 4-wire photoelectronic smoke detector that uses
a state-of-the-art optical sensing chamber. This detector also provides
restorable, 135˚F fixed-temperature heat detection. The photoelectronic
smoke sensor is isolated from the fixed-temperature heat sensor, providing a self-resetting, local audible smoke alarm that does not alarm at the
panel. Only the fixed-temperature heat sensor will cause the 2112/24AITR
to alarm at the panel and the relay to change its state.
In addition, a piezoelectric horn in each detector produces an interrupted,
85 dBA tone when the individual detector alarms or when the supply voltage polarity is reversed.
NOTE: In order for all detectors on a loop to sound when the panel
alarms, the panel must reverse the supply voltage polarity to that
loop upon alarm. For panels that do not reverse the polarity during
alarm, a reversing relay, such as System Sensor’s RR-2, must be
used. The RR-2 is designed to allow all the detectors in the same
loop to sound when one of the detectors goes into alarm. Some panels may require the use of programmable outputs. Refer to System
Sensor literature for further information on the RR-2.
Installation of this detector is simplified by the use of a mounting bracket
and a plug-in screw terminal block that can be prewired to the system,
allowing the detector to be easily installed or removed for cleaning. The
detector’s sensitivity can be tested in place using the MOD400R Test
Module.
An LED on the detector provides a local visual indication of the detector’s
status. If power is applied to the detector and it is functioning normally in
standby within the listed sensitivity range, the status LED blinks every ten
seconds. The LED also latches on in alarm.
If the LED stops blinking, the unit should be removed for maintenance
and inspection.
Mounting
Each 2112/24AITR detector is supplied with a mounting bracket that permits the detector to be mounted:
1. To a single gang box, or
2. Directly to a 31⁄2 inch or 4 inch octagonal box, or
3. To a 4 inch square electrical box by using a plaster ring.
4. Directly to the ceiling using drywall anchors, if permitted by local
codes and/or the authority having jurisdiction.
Tamper-resistant Feature
This detector includes a tamper-resistant feature that prevents its removal
from the bracket without the use of a tool. To make the detector tamperresistant, remove the smaller tab by breaking it at the scribed line on the
tamper resistant tab on the detector mounting bracket (see Figure 3), then
install the detector. To remove the detector from the bracket once it has
been made tamper resistant, use a small screwdriver to depress the tamper-resistant tab, located in the slot on the mounting bracket, and turn the
detector counterclockwise.
A78-1171-01
A78-1171-02
Figure 2. Surface mounting of 2112/24AITR smoke detector on
31⁄2-inch and 4-inch octagonal box:
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