System Sensor 2112-24D, 2112-24TD User Manual

INSTALLATION AND MAINTENANCE INSTRUCTIONS

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
CONTROL

PANEL

INITIATING

LOOP

+

–

+

–

P

W

R

+
+

–

+

–

+

–

N.O.

C

P

W

R

+
+

–

N.O.

C

: Observe polarity in power and initiating loops when wiring.

NOTE

2112/24D(A) and 2112/24TD(A)
Photoelectronic Smoke Detectors

3825 Ohio Avenue, St. Charles, Illinois 60174

1-800-SENSOR2, FAX: [phone]

A Division of Pittway

IMPORTANT: OBSERVE POLARITY

This detector requires that you observe polarity when wiring. If wiring polarity is not observed on the
initiating loop, the unit will send an alarm signal to the control panel to signify incorrect wiring.

Figure 1. Wiring diagram for the 2112/24D(A) and 2112/24TD(A) detectors:

Before Installing

Please thoroughly read the System Sensor manual I56-407,
Guide for Proper Use of System Smoke Detectors, which
provides detailed information on detector spacing, place-

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.
ment, zoning, wiring, and special applications. Copies of
this manual are available at no charge from System Sensor.
(For installation in Canada, refer to CAN/ULC-S524-M91,
Standard for the Installation of Fire Alarm Systems, and
CEC Part 1, sec. 32.)

NOTICE: This manual should be left with the owner/user
of this equipment.

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, the status LED blinks

every ten seconds. The LED also latches on in alarm.

Models 2112/24D(A) and 2112/24TD(A) feature a visual

indication that maintenance is required – if the sensing

chamber drifts out of its sensitivity limits, the LED ceases
IMPORTANT: This detector must be tested and maintained

to blink.
following NFPA 72 requirements. The detector should be
cleaned at least once a year.

General Description

Model 2112/24D(A) is a 4-wire photoelectronic smoke de­tector that uses a state-of-the-art optical sensing chamber.
This detector is designed to provide open area protection.
Model 2112/24TD(A) features a restoreable, built-in, xed­temperature (135°F) thermal detector.

Installation of these detectors is simplied by the use of a
mounting bracket and a plug-in screw terminal block that

D200-62-00 1 I56-932-07

Mounting

Each 2112/24D(A) and 2112/24TD(A) 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.

Tamper-resistant Feature

This detector includes a tamper-resistant feature that pre-

vents its removal from the bracket without the use of a

A78-2336-03

CAUTION

WARNING

Specications

Diameter: 5.5 inches (140 mm)
Height (including mounting bracket): 1.7 inches (43 mm)
Weight: 5.3 oz. (150 g)
Operating Temperature Range
Model 2112/24D(A): 32° to 120°F (0° to 50°C)
Model 2112/24TD(A): 32° to 100°F (0° to 39°C)
Operating Humidity Range: 10% to 93% Relative Humidity, Noncondensing
Latching Alarm: Reset by momentary power interruption
Heat Sensor (2112/24TD(A) only): 135°F Fixed Temperature Electronic Thermistor

Electrical Ratings

System Voltage (nominal): 12 or 24 VDC
Minimum: 8.5 VDC
Maximum: 35 VDC
Maximum Ripple Voltage: 30% of nom. Voltage (peak to peak)
Standby Current: 50 µA maximum
Alarm Current: 17 mA typical, 23 mA max. at 12V
19 mA typical, 25 mA max. at 24V
Reset Voltage: 0.8 VDC minimum
Reset Time: 0.3 seconds maximum
Start-up Time: 30 seconds maximum (after 60 sec. reset)
EOL Relay: A77-716B, 12/24 Volt
Alarm Initiation Contact Ratings
Resistive Load: 0.1A @ 35 VDC

Figure 2. Surface mounting of 2112/24D(A) smoke
detector on 31/2-inch and 4-inch octagonal box:

A78-2563-00

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

Be certain to observe polarity when wiring.

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 re.

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 re 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
specications for allowable loop resistance. Consult the
control panel specications 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

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

Remove power from the control unit or initiating device
circuits before installing detectors.

to connect smoke detectors to control panels and accessory

D200-62-00 2 I56-932-07