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

CAUTION

TAMPER SLOT
(DEPRESS TAB TO
REMOVE DETECTOR)

TAMPER RESISTANT TAB
(CUT OFF SMALL TAB TO
ACTIVATE TAMPER-RESIST
FEATURE)

ALIGNMENT
ARROWS

LED

TEST MODULE
SOCKET

RECESSED TEST
SWITCH

PUSH RECESSED
SWITCH WITH A

0.18

″ MAX. DIAMETER TOOL

Figure 3. 2112/24D(A) and 2112/24TD(A) smoke detector mounting bracket:

A78-2333-01

1. Wire the plug-in screw terminal block per Figure 3 and

plug the terminal block into the detector.

2. Align the arrows on the detector with the arrows on the

mounting bracket.

3. Turn the detector clockwise in the mounting bracket un-

til it clicks into place.

4. After all detectors have been installed, apply power to

the control unit or initiating device circuits.

NOTE: This detector has a feature that will signal an

alarm at the control panel if wiring polarity is
incorrect.

5. Test the detector as described in TESTING.

6. Reset the detector at the system control panel.

7. Notify the proper authorities the system is in operation.

Dust covers are an effective way to limit the entry of dust
into smoke detector sensing chambers. However, they may
not completely prevent airborne dust particles from en­tering the detector. Therefore, System Sensor recommends
the removal of detectors before beginning construction or
other dust producing activity. Be sure to remove dust covers
from any sensors that were left in place during construction
as part of returning the system to service.

Testing

NOTE: Before testing, notify the proper authorities that the

smoke detector system is undergoing maintenance
and will be temporarily out of service. Disable the
zone or system undergoing maintenance to prevent
unwanted alarms.

Detectors must be tested after installation and following

periodic maintenance. Test the 2112/24D(A) as follows:

A. Test Switch

1. A recessed test switch is located on the detector hous­ing (See Figure 4).

2. Press and hold the recessed test switch with a 0.18
inch maximum diameter tool such as an allen wrench
or small screwdriver.

3. The detector’s LED should light within 5 seconds.

B. Test Module (System Sensor Model No. MOD400R)
The MOD400R test module can be used with a DMM

or analog voltmeter to check the detector sensitivity as

described in the test module’s manual.
C. Smoke Entry Test
Hold a smoldering punk stick or cotton wick at the side

of the detector and gently blow smoke through the de-

tector until the unit alarms.
D. Direct Heat Method (Model 2112/24TD(A) only – Hair

dryer of 1000-1500 watts)
Direct the heat toward either of the side thermistors.

Hold the heat source about 12 inches from the detector

in order to avoid damage to the plastic. The detector will

reset only after it has had sufcient time to cool and the

power source has been momentarily interrupted.

Both smoke and heat detection testing are recommended
for verifying system protection capability.

A detector that fails to activate with any of the above tests
should rst be cleaned as outlined in MAINTENANCE. If
the detector still fails to activate, return it for repair.

Notify the proper authorities the system is back in
operation.

Figure 4. Top and side views showing position of test switch:

D200-62-00 3 I56-932-07

A78-2564-00

WARNING

REMOVABLE
HOUSING

REMOVABLE
SCREEN

SENSING CHAMBER
COVER

BASE

SENSING
CHAMBER

NOTE: Before removing the detector, notify the proper

authorities that the smoke detector system is un­dergoing maintenance and will be temporarily out
of service. Disable the zone or system undergoing
maintenance to prevent unwanted alarms.

NOTE: (Model 2112/24TD(A) only) Before removing the

detector cover, note the position of the thermistors.
Make sure the thermistors are not bent over when
the housing is replaced.

1. Remove the detector housing by gently prying the four
housing tabs on the bottom of the base with a small­bladed screwdriver and pull the housing from the base.
Use caution to avoid damaging the thermistors (2112/
24TD(A) only).

2. Vacuum the screen carefully without removing it.

3. Remove screen assembly, pulling straight out (see Fig­ure 5).

4. Remove the sensing chamber cover.

5. Clean the sensing chamber by vacuuming or blowing
out dust and particles.

6. Replace the sensing chamber cover, aligning the arrow
on the cover top with the arrow on the printed circuit
board.

7. Replace the screen by placing the screen assembly over
the sensing chamber cover and twisting until it snaps
into place.

Figure 5. Removal of cover and screen for cleaning:Maintenance

A78-2565-00

8. Replace the housing by aligning the three triangular
slots on the base with their counterparts on the hous­ing. Gently press the housing until it locks in place.
Check to make sure that the thermistors are in the up­right position (2112/24TD(A)).

9. Reinstall the detector.

10. Notify the proper authorities that the system is back in
operation.

This smoke detector is designed to activate and initiate emergency action, but will
do so only when it is used in conjunction with an authorized re alarm system. This
detector must be installed in accordance with NFPA standard 72. (For installation
in Canada, refer to CAN/ULC-S524-M91, Standard for the Installation of Fire Alarm
Systems, and CEC Part 1, sec. 32.)
Smoke detectors will not work without power. AC or DC powered smoke detectors
will not work if the power supply is cut off.

Smoke detectors will not sense res which start where smoke does not reach the
detectors. Smoldering res typically do not generate a lot of heat which is needed

to drive the smoke up to the ceiling where the smoke detector is usually located.
For this reason, there may be large delays in detecting a smoldering re with either
an ionization type detector or a photoelectric type detector. Either one of them may
alarm only after aming has initiated which will generate the heat needed to drive
the smoke to the ceiling.
Smoke from res in chimneys, in walls, on roofs or on the other side of a closed
door(s) may not reach the smoke detector and alarm it. A detector cannot detect a
re developing on another level of a building quickly or at all. For these reasons, de­tectors shall be located on every level and in every bedroom within a building.
Smoke detectors have sensing limitations, too. Ionization detectors and photo­electric detectors are required to pass re tests of the aming and smoldering type.
This is to ensure that both can detect a wide range of types of res. Ionization detec­tors offer a broad range of re sensing capability but they are somewhat better at

date of manufacture. System Sensor makes no other express warranty for this smoke

System Sensor warrants its enclosed smoke detector to be free from defects in materials and workmanship under normal use and service for a period of three years from
detector. No agent, representative, dealer, or employee of the Company has the

authority to increase or alter the obligations or limitations of this Warranty. The
Company’s obligation of this Warranty shall be limited to the repair or replacement
of any part of the smoke detector which is found to be defective in materials or work­manship under normal use and service during the three year period commencing
with the date of manufacture. After phoning System Sensor’s toll free number
800-SENSOR2 (736-7672) for a Return Authorization number, send defective units
postage prepaid to: System Sensor, Repair Department, RA #__________, 3825 Ohio
Avenue, St. Charles, IL 60174. Please include a note describing the malfunction and

D200-62-00 4 I56-932-07

The Limitations of Property Pr otection Smoke Detectors

detecting fast aming res than slow smoldering res. Photoelectric detectors sense
smoldering res better than aming res which have little, if any, visible smoke.
Because res develop in different ways and are often unpredictable in their growth,
neither type of detector is always best, and a given detector may not always provide
early warning of a specic type of re.
In general, detectors cannot be expected to provide warnings for res resulting from
inadequate re protection practices, violent explosions, escaping gases which ignite,
improper storage of ammable liquids like cleaning solvents which ignite, other sim­ilar safety hazards, arson, smoking in bed, children playing with matches or lighters,
etc. Smoke detectors used in high air velocity conditions may have a delay in alarm
due to dilution of smoke densities created by frequent and rapid air exchanges. Ad­ditionally, high air velocity environments may create increased dust contamination,
demanding more frequent maintenance.
To keep your equipment in excellent working order, ongoing maintenance is re­quired per the manufacturer’s recommendations and UL and NFPA standards. At
a minimum, the requirements of Chapter 7 of NFPA 72, the National Fire Alarm
Code, shall be followed. A preventative maintenance agreement should be arranged
through the local manufacturer’s representative. Though smoke detectors are de­signed for long life, they may fail at any time. Any smoke detector, re alarm equip­ment, or any component of that system which fails shall be repaired or replaced as
soon as possible.

Three-Year Limited Warranty

suspected cause of failure. The Company shall not be obligated to repair or replace
units which are found to be defective because of damage, unreasonable use, modi­cations, or alterations occurring after the date of manufacture. In no case shall the
Company be liable for any consequential or incidental damages for breach of this or
any other Warranty, expressed or implied whatsoever, even if the loss or damage is
caused by the Company’s negligence or fault. Some states do not allow the exclusion
or limitation of incidental or consequential damages, so the above limitation or ex­clusion may not apply to you. This Warranty gives you specic legal rights, and you
may also have other rights which vary from state to state.

© System Sensor 1998