System Sensor 2112-24AT User Manual
INSTALLATION AND MAINTENANCE INSTRUCTIONS
2112/24AT
Photoelectronic Smoke Detector with
Fixed Heat and Integral Temp-3 Sounder
Figure 1. Wiring diagram for the 2112/24AT detector:
IMPORTANT: OBSERVE POLARITY
As with all sounder models, polarity must be observed on the power connections.
+
POWER
TO
DETECTORS
–
+
P
W
+
R
–
A
UL LISTED
COMPATIBLE
CONTROL
PANEL
INITIATING
LOOP
ALARM
CONTACT
A
NOT USED
OPTIONAL CLASS A WIRING
P
+
W
+
R
–
A
ALARM
CONTACT
A
NOT USED
3825 Ohio Avenue, St. Charles, Illinois 60174
1-800-SENSOR2, FAX: 630-377-6495
EOL POWER
SUPERVISION
RELAY (SHOWN
ENERGIZED)
A77-716 12/24V
EOL RESISTOR
SPECIFIED BY
PANEL
MANUFACTURER
A78-2336-14
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
Alarm Initiation
Contact Rating, Resistive Load: 1A @ 30 VDC
Special Considerations: Due to the built-in temporal pattern, use this detector only with a non-coded
power supply.
Before Installing
Please thoroughly read the System Sensor manual I56-407,
NOTICE: This manual shall be left with the owner/user of
this equipment.
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.
D200-82-00 1 I56-1237-01R
IMPORTANT: This detector must be tested and maintained
following NFPA 72 requirements. The detector should be
cleaned at least once a year.
Figure 2. Surface mounting of 2112/24AT smoke
detector on 31/2-inch and 4-inch octagonal box:
A78-2563-05
General Description
Model 2112/24AT is a 4-wire photoelectronic smoke detector that uses a state-of-the-art optical sensing chamber.
The detector also provides restorable, 135˚F fixed-temperature heat detection. The unit has a heat detection unit that
is integrated with the photoelectronic sensor.
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 these detectors 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.
Figure 3. 2112/24AT smoke detector mounting bracket:
TAMPER SLOT
(DEPRESS TAB TO
REMOVE DETECTOR)
If the LED stops blinking, the unit should be removed for
maintenance and inspection.
Mounting
Each 2112/24AT 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 3-1/2 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 tamper-resistant, 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.
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.
TAMPER RESISTANT TAB
(CUT OFF SMALL TAB TO
ACTIVATE TAMPER-RESIST
FEATURE)
ALIGNMENT
ARROWS
A78-2333-01
D200-82-00 2 I56-1237-01R
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