System Sensor 2251 User manual

D200-03-00 1 I56-582-04
2251 Intelligent Photoelectronic
Smoke Sensor
INSTALLATION AND MAINTENANCE INSTRUCTIONS
A Division of Pittway
3825 Ohio Avenue, St. Charles, Illinois 60174
1-800-SENSOR2, FAX: [phone]
Before Installing
This sensor must be installed in compliance with the con-
trol panel system installation manual. The installation
must meet the requirements of the Authority Having Juris-
diction (AHJ). Sensors offer maximum performance when
installed in compliance with the National Fire Protection
Association (NFPA); see NFPA 72.
General Description
Model 2251 is a plug-in type smoke sensor that combines a
photoelectronic sensing chamber with addressable-analog
communications. The sensor transmits an analog represen-
tation of smoke density over a communication line to a
control panel. Rotary-decade switches are provided for set-
ting the sensor’s address. Two LEDs on the sensor are con-
trolled by the panel to indicate sensor status. An output is
provided for connection to an optional remote LED annun-
ciator (P/N RA400Z).
The 2251 requires compatible addressable communica-
tions to function properly. Connect this sensor to listed-
compatible control panels only.
Specifications
Operating Voltage Range: 15 to 32 VDC
Max. Avg. Standby Current: 330µA@ 24 VDC (one communication every 5 sec. with LED blink enabled)
Max. Alarm Current (LED on:) 6.5 mA @ 24 VDC
Operating Humidity Range: 10% to 93% Relative Humidity, noncondensing
Operating Temperature Range: 0° to 49°C (32° to 120°F)
Height: 1.7 inches (43 mm) installed in B210LP Base
Diameter: 6.2 inches (155 mm) installed in B210LP Base
4.1 inches (104 mm) installed in B501 Base
Weight: 3.6 oz. (102 g)
Spacing
System Sensor recommends spacing sensors in compliance
with NFPA 72. In low air flow applications with smooth
ceilings, space sensors 30 feet apart. For specific informa-
tion regarding sensor spacing, placement, and special ap-
plications, refer to NFPA 72 or the System Sensor Guide For
Proper Use of System Smoke Detectors, available at no
charge from System Sensor (P/N I56-407-XX).
Wiring Instructions
All wiring must be installed in compliance with the Na-
tional Electrical Code, applicable local codes, and any spe-
cial requirements of the Authority Having Jurisdiction.
Proper wire gauges should be used. The installation wires
should be color-coded to limit wiring mistakes and ease
system troubleshooting. Improper connections will prevent
a system from responding properly in the event of a fire.
Remove power from the communication line before in-
stalling sensors.
All wiring must conform to applicable local codes, ordi-
nances, and regulations.
1. Wire the sensor base (supplied separately) per the wir-
ing diagram, see Figure 1.
2. Set the desired address on the sensor address switches,
see Figure 2.
3. Install the sensor in to the sensor base. Push the sensor
into the base while turning it clockwise to secure it in
place.
4. After all sensors have been installed, apply power to the
control unit and activate the communication line.
5. Test the sensor(s) as described in the TESTING section
of this manual.

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Dust covers provide limited protection against airborne
dust particles during shipping. Dust covers must be re-
moved before the sensors can sense smoke. Remove sen-
sors prior to heavy remodeling or construction.
Testing
Before testing, notify the proper authorities that the system
is undergoing maintenance, and will temporarily be out of
service. Disable the system to prevent unwanted alarms.
All sensors must be tested after installation and periodi-
cally thereafter. Testing methods must satisfy the Authority
Having Jurisdiction (AHJ). Sensors offer maximum perfor-
mance when tested and maintained in compliance with
NFPA 72.
The sensor can be tested in the following ways:
A. Functional: Magnet Test (P/N M02-04-01)
This sensor can be functionally tested with a test mag-
net. The test magnet electronically simulates smoke in
the sensing chamber, testing the sensor electronics and
connections to the control panel.
1. Hold the test magnet in the magnet test area as shown
in Figure 3.
2. The sensor should alarm the panel.
Two LEDs on the sensor are controlled by the panel to
indicate sensor status. Coded signals, transmitted
from the panel, can cause the LEDs to blink, latch on,
or latch off. Refer to the control panel technical docu-
A78-2461-00
mentation for sensor LED status operation and ex-
pected delay to alarm.
B. Sensitivity: Test Module (MOD400R)
A sensitivity test module socket is provided for checking
the sensor’s sensitivity with the MOD400R Test Module
(supplied separately). Use the test module with a digital
or analog voltmeter to check the sensor sensitivity. An
acceptable voltage range is stamped on the back of the
sensor. Test the sensor as described in the test module’s
manual.
C. Smoke Entry: Aerosol Generator (Gemini 501)
The GEMINI model 501 aerosol generator can be used
for smoke entry testing. Set the generator to represent
4%/ft to 5%/ft obscuration as described in the GEMINI
501 manual. Using the bowl shaped applicator, apply
aerosol until the panel alarms.
A sensor that fails any of these tests should be cleaned as
described under CLEANING, and retested. If the
sensor fails after cleaning, it must be replaced and returned
for repair.
When testing is complete, restore the system to normal op-
eration and notify the proper authorities that the
system is back in operation.
Figure 1. Wiring diagram:

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A78-2462-00
A78-2463-08
Cleaning
It is recommended that the detector be removed from its
mounting base to facilitate cleaning. The detector is
cleaned as follows:
NOTE: Before removing the detector, notify the proper au-
thorities that the smoke detector system is under-
going maintenance and will be temporarily out of
service. Disable the zone or system undergoing
maintenance to prevent unwanted alarms.
1. Remove the detector cover by prying away the four
side tabs with a small-bladed screwdriver, and then
pulling the cover from the base.
2. Vacuum the screen carefully without removing it. If
further cleaning is required continue with Step 3, oth-
erwise skip to Step 8.
3. Remove the screen assembly by pulling it straight out
(see Figure 4).
4. Remove the sensing chamber cover by pulling it
straight out.
5. Clean the vaned chamber piece by vacuuming or
blowing out dust and particles.
6. Replace the sensing chamber cover, aligning the arrow
on the top with arrow on the printed circuit board.
7. To replace the screen, place it over the chamber as-
sembly, turning it until it snaps into place.
8. Replace the cover using the test module socket and
LEDs to align the cover and then gently pushing it un-
til it locks into place.
9. Reinstall the detector.
10. Test the detector as described in TESTING.
11. Reconnect disabled circuits.
12. Notify the proper authorities that the system is back
on line.
A78-2460-00
Figure 2. Rotary decade address switches:
Figure 3. Test magnet position:
Figure 4. Sensor assembly:

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Three-Year Limited Warranty
System Sensor warrants its enclosed smoke detector to be free from de-
fects in materials and workmanship under normal use and service for a
period of three years from date of manufacture. System Sensor makes no
other express warranty for this smoke 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 work-
manship under normal use and service during the three year period com-
mencing 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 Depart-
ment, RA #__________, 3825 Ohio Avenue, St. Charles, IL 60174. Please
include a note describing the malfunction and 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, modifica-
tions, 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 conse-
quential damages, so the above limitation or exclusion may not apply to
you. This Warranty gives you specific legal rights, and you may also have
other rights which vary from state to state.
This smoke detector is designed to activate and initiate emergency ac-
tion, but will do so only when it is used in conjunction with an authorized
fire alarm system. This detector must be installed in accordance with
NFPA standard 72.
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 fires which start where smoke does not
reach the detectors. Smoldering fires 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 de-
lays in detecting a smoldering fire with either an ionization type detector
or a photoelectric type detector. Either one of them may alarm only after
flaming has initiated which will generate the heat needed to drive the
smoke to the ceiling.
Smoke from fires 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 fire 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 fire tests of the flaming and
smoldering type. This is to ensure that both can detect a wide range of
types of fires. Ionization detectors offer a broad range of fire sensing capa-
bility but they are somewhat better at detecting fast flaming fires than
slow smoldering fires. Photoelectric detectors sense smoldering fires better
than flaming fires which have little, if any, visible smoke. Because fires de-
velop in different ways and are often unpredictable in their growth, nei-
ther type of detector is always best, and a given detector may not always
provide early warning of a specific type of fire.
In general, detectors cannot be expected to provide warnings for fires re-
sulting from inadequate fire protection practices, violent explosions, es-
caping gases which ignite, improper storage of flammable liquids like
cleaning solvents which ignite, other similar safety hazards, arson, smok-
ing 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 dilu-
tion of smoke densities created by frequent and rapid air exchanges. Addi-
tionally, high air velocity environments may create increased dust
contamination, demanding more frequent maintenance.
Smoke detectors cannot last forever. Smoke detectors contain electronic
parts. Even though smoke detectors are made to last over 10 years, any
part can fail at any time. Therefore, smoke detectors shall be replaced after
being in service for 10 years. The smoke detector system that this detector
is used in must be tested regularly per NFPA 72. This smoke detector
should be cleaned regularly per NFPA 72 or at least once a year.
The Limitations of Property Protection Smoke Detectors