System Sensor 2112_24AT Photoelectronic - Manual (Page 2)

D200-82-00 2 I56-1237-01R
TAMPER SLOT
(DEPRESS TAB TO
REMOVE DETECTOR)
TAMPER RESISTANT TAB
(CUT OFF SMALL TAB TO
ACTIVATE TAMPER-RESIST
FEATURE)
ALIGNMENT
ARROWS
Figure 2. Surface mounting of 2112/24AT smoke
detector on 3 1 /
2
-inch and 4-inch octagonal box:
A78-2563-05
Figure 3. 2112/24AT smoke detector mounting bracket:
A78-2333-01
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 permit-
ted by local codes and/or the authority having jurisdic-
tion.
Tamper-resistant Feature
This detector includes a tamper-resistant feature that pre-
vents 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 screw-
driver to depress the tamper-resistant tab, located in the
slot on the mounting bracket, and turn the detector coun-
terclockwise.
Wiring Installation Guidelines
All wiring must be installed in compliance with the Na-
tional Electrical Code, applicable local codes, and any spe-
cial 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 al-
lowed for the control panel being used before wiring the
detector loops.
General Description
Model 2112/24AT is a 4-wire photoelectronic smoke detec-
tor that uses a state-of-the-art optical sensing chamber.
The detector also provides restorable, 135˚F fixed-tempera-
ture 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 re-
verse 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 re-
quire 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 sensi-
tivity range, the status LED blinks every ten seconds. The
LED also latches on in alarm.