System Sensor 2W-B, 2WT-B, 4W-B & 4WT-B - Installation Guide

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Document Transcript



3825 Ohio Avenue, St. Charles, Illinois 60174
1-800-SENSOR2, FAX: 630-377-6495

Photoelectric Smoke Detector
Models: 2W-B, 2WT-B, 4W-B, 4WT-B

Electrical Specifications 2-wire 4-wire
System Voltage –Nominal:

12/24 Volts Non-polarized
8.5 8.5 Volts
35 35 Volts
Max. Ripple Voltage:

30 % peak to peak of applied voltage
Max. Standby Current:

50 µA average
Peak Standby Current:


— µA
Max. Alarm Current:

20 mA 12 Volt Systems
(For 2W-B and 2WT-B, panel must limit current)
23 mA 24 Volt Systems
Alarm Contact Ratings:

0.5 Amp @ 30 V AC/DC
Alarm Reset Time:

0.3 sec
Max. Start-up Capacitance:

— µF
Latching Alarm: Reset by momentary power interruption
Maximum Initial
Start-up Time:

15 sec
Alarm Verification*
Start-up Time:

15 sec
*Assumes the panel’s alarm verification reset time is 10 seconds or less. Should the alarm verification reset exceed 10 seconds, use the maximum initial start-up time.
Physical Specifications
Heat Sensor (Model 2WT-B and 4WT-B):
135°F (57.2°C)
Freeze Trouble (Model 2WT-B and 4WT-B):
41°F (5°C)
Operating Temperature Range:
2W-B and 4W-B:

32 to 120°F (0 to 49°C)
2WT-B and 4WT-B:

32 to 100°F (0 to 37.8°C)
Operating Humidity Range:

0 to 95% RH non-condensing
Storage Temperature Range:

–4 to 158°F (–20 to 70°C)
Diameter (including base):

5.3 inches
Height (including base):

2.0 inches
6.3 oz.
Before Installing
Please read thoroughly System Sensor manual A05-1003, Applications Guide
for System Smoke Detectors, which provides detailed information on detector
spacing, placement, zoning, wiring, and special applications. Copies of this
manual are available from System Sensor at no charge.

Installation of the 2W-B, 2WT-B, 4W-B, and 4WT-B detectors is simplified by
the use of a mounting base that may be pre-wired to the system, allowing the
detector to be easily installed or removed. The mounting base installation is
further simplified by the incorporation of features compatible with drywall

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

Two LEDs on the detector provide a local visual indication of the detector’s status:

IMPORTANT: This detector must be tested and maintained regularly following
NFPA 72 requirements. At a minimum, cleaning should be performed annually.
General Description
Models 2W-B and 2WT-B are 2-wire photoelectric smoke detectors; models
4W-B and 4WT-B are 4-wire photoelectric smoke detectors. All models incorporate a state-of-the-art optical sensing chamber and an advanced microprocessor. The microprocessor allows the detector to automatically adjust its
sensitivity back to the factory setting when it becomes more sensitive due to
contaminants settling in its chamber. In order for this feature to work properly, the chamber must never be opened while power is applied to the smoke
detector. This includes cleaning, maintenance or screen replacement. Should
it become necessary, the screen/sensing chamber is field replaceable. Models 2WT-B and 4WT-B also feature a restorable, built-in, fixed temperature
(135°F) thermal detector and are also capable of sensing a freeze condition if
the temperature is below 41°F.

Table 1: Detector LED Modes
Normal (standby)
Out of sensitivity
Freeze Trouble

Blink 10 sec

Blink 5 sec
Blink 10 sec

After an initial power-up delay, the red and green LEDs will blink synchronously once every ten seconds. It will take approximately 80 seconds for the
detector to finish the power-up cycle (see Table 2).
Table 2: Power-up Sequence for LED Status Indication*
Initial LED Status Indication
Initial LED Status Indication

All i3 Series detectors are designed to provide open area protection. Two-wire
models must be used with compatible UL Listed panels only.
When used with an i3 Series compatible control panel or the i3 Series 2WMOD module (refer to installation manual D500-46-00), the 2W-B and 2WT-B
are capable of generating a “maintenance needed” signal. The 2W-MOD can
indicate a need for cleaning, replacement, or a freeze condition (2WT-B only)
at the control panel or module.


Green LED
Blink 10 sec
Blink 5 sec

80 seconds
4 minutes

(if excessive electrical noise is present)
*Refer to Electrical Specifications for start-up time in conjunction with panel
alarm verification.



NOTE: If, during power-up, the detector determines there is excessive electrical noise in the system such as those caused by improper grounding of the
system or the conduit, both LEDs will blink for up to 4 minutes before displaying detector status (see Table 2).

• In wet or excessively humid areas, or next to bathrooms with showers.

After power-up has completed and the detector is functioning normally within
its listed sensitivity range, the green LED blinks once every five seconds. If the
detector is in need of maintenance because its sensitivity has shifted outside
the listed limits, the red LED blinks once every five seconds. When the detector is in the alarm mode, the red LED latches on. The LED indication must not
be used in lieu of the tests specified under Testing. In a freeze trouble condition, the red LED will blink once every 10 seconds (refer to Table 1).

Consult NFPA 72, the local Authority Having Jurisdiction (AHJ), and/or applicable codes for specific information regarding the spacing and placement
of smoke detectors.

• In dusty, dirty, or insect-infested areas.
• Near fresh air inlets or returns or excessively drafty areas. Air conditioners, heaters, fans, and fresh air intakes and returns can drive smoke
away from the detector.

Smoke detectors are not to be used with detector guards unless the combination has been evaluated and found suitable for that purpose.

To measure the detector’s sensitivity, the i3 Series Model SENS-RDR Infrared
Sensitivity Reader tool should be used. (See Figure 4.)

Wiring Installation Guidelines
All wiring must be installed in compliance with the National Electrical Code,
applicable state and local codes, and any special requirements of the local
Authority Having Jurisdiction.

Models 2W-B and 2WT-B also include an output that allows an optional Model
RA400Z Remote Annunciator to be connected.
Each i3 Series detector is supplied with a mounting base that can be

Proper wire gauges should be used. The conductors used to connect smoke
detectors to the alarm control panel and accessory devices should be colorcoded to reduce the likelihood of wiring errors. Improper connections can
prevent a system from responding properly in the event of a fire.

1. To a single gang box, or
2. To a 31⁄2-inch or 4-inch octagonal box, or
3. To a 4-inch square box with a plaster ring, or
4. Direct mount or to ceiling using drywall fasteners (Figure 2).
Figure 1: Mounting of Detector

The screw terminals in the mounting base will accept 14–22 gauge wire. For
best system performance, all wiring should be installed in separate grounded
conduit; do not mix fire alarm system wiring in the same conduit as any other
electrical wiring. Twisted pair may be used to provide additional protection
against extraneous electrical interference.
Wire connections are made by stripping approximately 1⁄4-inch of insulation
from the end of the feed wire, inserting it into the proper base terminal, and
tightening the screw to secure the wire in place.
Two-Wire Compatibility
System Sensor two-wire smoke detectors are marked with a compatibility
identifier located on the label on the back of the product. For two-wire models
2W-B and 2WT-B, connect detectors only to compatible alarm control panels
as identified by System Sensor’s compatibility chart. This chart contains the
current list of detectors and UL Listed compatible control units. A copy of this
list is available from System Sensor upon request.


The i3 Series heads and bases are keyed so that a 2-wire head will only mount
to a 2-wire base, and a 4-wire head will only mount to a 4-wire base. The
heads and bases are clearly identified as either 2-wire or 4-wire. When mounting the i3 Series, ensure that the head is mounted to the correct base.

Wiring Diagrams
Figure 3a: Wiring Diagram, 2W-B and 2WT-B

Tamper-Resistant Feature
The i3 Series detectors include a tamper-resistant feature that prevents removal
from the mounting base without the use of a tool. To engage the tamper-resistant feature, cut the small plastic tab located on the mounting base (Figure
2), and then install the detector. To remove the detector from the base once it
has been made tamper resistant, use a small screwdriver to depress the square
tamper release tab, located on the skirt of the mounting base, and turn the
detector counterclockwise.

2-WIRE +


(5) RA –

(4) RA +

(3) – IN/OUT

2W-B or

2W-B or


(2) + OUT

(1) + IN

(5) RA –

(4) RA +

(3) – IN/OUT

(2) + OUT

Figure 2: Tamper-Resistant Feature

(1) + IN




Figure 3b: Wiring Diagram, 4W-B and 4WT-B





4W-B or

(5) COM

(4) NO

(3) – IN/OUT

(2) + OUT

(1) + IN

4W-B or

(5) COM

(4) NO

(3) – IN/OUT


Do NOT Install Detectors in the Following Areas:
• In or near areas where particles of combustion are normally present
such as kitchens; in garages (vehicle exhaust); near furnaces, hot water
heaters, or gas space heaters.

(2) + OUT


(1) + IN



• In very cold or very hot areas.



2-Wire i3 Detector Wired in Style D Configuration:

B. Smoke Entry Test
Hold a smoldering punk stick or cotton wick at the side of the detector and
gently blow the smoke through the detector until it alarms.


Any 2-wire i3 smoke detector (2W-B, 2WT-B, 2WTA-B, or 2WTR‑B) wired
in the Style D initiating device circuit (IDC) configuration requires the use
of a 2W-MOD2 module. This is because fire alarm control panels vary by
manufacturer on the implementation of Style D circuits. Therefore, the only
way to insure proper operation of 2-wire i3 smoke detectors (2W-B, 2WT-B,
2WTA-B, or 2WTR-B) on Style D IDC’s is to use a 2W-MOD2 module. Refer to
the 2W-MOD2 installation manual, document D500-46‑00, for Style D wiring
diagrams. The 2W-MOD2 installation manual may be downloaded from the
System Sensor web site at

C. Direct Heat Method (models 2WT-B and 4WT-B only)
Using a 1000-1500 watt hair dryer, direct the heat toward either of the thermistors. Hold the heat source about 12 inches from the detector to avoid damage
to the plastic.


Notify the proper authorities when the system is back in service.

NOTE: For the above tests, the detector will reset only after the power source
has been momentarily interrupted.
If a detector fails any of the above test methods, its wiring should be checked
and it should be cleaned as outlined in the Maintenance section. If the detector still fails, it should be replaced.
Loop Verification (models 2W-B and 2WT-B only)
Loop verification is provided by the EZ Walk loop test feature. This feature is
for use with i3 Series compatible control panels or the i3 Series 2W-MOD module only. The EZ Walk loop test verifies the initiating loop wiring and provides
visual status indication at each detector.


Remove power from alarm control unit or initiating device circuits before installing detectors.
NOTE: To install units so that corresponding LEDs are lined up, refer to the
“Green LED” indicator on the base.
1. Wire the mounting base screw terminals per Figure 3a or Figure 3b, as
2. Place detector on the base and rotate clockwise. The detector will drop
into the base and lock into place with a “click”.
3. After all detectors have been installed, apply power to the alarm control
4. Test each detector as described in Testing.
5. Reset all the detectors at the alarm control unit.
6. Notify the proper authorities that the system is in operation.

1. Ensure proper wiring and power is applied. Wait approximately six minutes before performing EZ Walk test.
2. Place control panel or module in EZ Walk Test mode (refer to panel manufacturer’s manual or 2W-MOD manual D500-46-00).
3. Observe the LEDs on each detector:
Table 3: EZ Walk Test Detector Modes
Green LED


Dust covers are an effective way to limit the entry of dust into the smoke detector sensing chamber. 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. When returning the system to service, be sure to remove the dust
covers from any detectors that were left in place during construction.


Proper Operation

Double blink 5 sec

Out of Sensitivity

Double Blink 5 sec

Freeze Condition

Double Blink 10 sec

he EZ Walk loop test must not be used instead of alarm
NOTE: Before performing maintenance on the detector, notify the proper authorities that maintenance is being performed and the system will be temporarily out of service. Disable the zone or system undergoing maintenance
to prevent any unwanted alarms. Power must be removed from the detector
before performing maintenance of any kind.
1. Remove the detector cover by turning counterclockwise. (See Figure 6.)
2. Vacuum the cover or use canned air to remove any dust or debris.
3. Remove the top half of the screen/sensing chamber by lifting straight up
(Figure 5).
4. Vacuum or use canned air to remove any dust or particles that are present on both chamber halves.
5. Replace the top half of the screen/sensing chamber by aligning the arrow
on the screen/sensing chamber with the arrow on the housing. Press
down firmly until the screen/sensing chamber is fully seated.
6. Replace the detector cover by placing it over the screen/sensing chamber
and turning it clockwise until it snaps into place.
7. Reinstall the detector and test. (See the Testing section.)
8. Notify the proper authorities when the system is back in service.

Detectors must be tested after installation and following maintenance.
NOTE: Before testing, notify the proper authorities that maintenance is being
performed and the system will be temporarily out of service. Disable the zone
or system undergoing maintenance to prevent any unwanted alarms.
Ensure proper wiring and power is applied. After power up, allow 80 seconds
for the detector to stabilize before testing.
Test i3 Series detectors as follows:
A. Test Switch
1. An opening for the recessed test switch is located on the detector housing (See Figure 4).
2. Insert a small screwdriver or allen wrench (0.18˝ max.) into the test
switch opening; push and hold.
3. If the detector is within the listed sensitivity limits, the detector’s red
LED should light within five seconds.
Figure 4: Recessed Test Switch Opening and SENS-RDR Position



0.18″ MAX.





Figure 5: Removing/Replacing Screen/Sensing Chamber




Please refer to insert for the Limitations of Fire Alarm Systems
Three-Year Limited Warranty
System Sensor warrants its enclosed smoke detector to be free from defects in materials
Department, RA #__________, 3825 Ohio Avenue, St. Charles, IL 60174. Please include a
and workmanship under normal use and service for a period of three years from date
note describing the malfunction and suspected cause of failure. The Company shall not
of manufacture. System Sensor makes no other express warranty for this smoke detecbe obligated to repair or replace units which are found to be defective because of damage,
tor. No agent, representative, dealer, or employee of the Company has the authority to
unreasonable use, modifications, or alterations occurring after the date of manufacture.
increase or alter the obligations or limitations of this Warranty. The Company’s obligation
In no case shall the Company be liable for any consequential or incidental damages for
of this Warranty shall be limited to the repair or replacement of any part of the smoke
breach of this or any other Warranty, expressed or implied whatsoever, even if the loss
detector which is found to be defective in materials or workmanship under normal use
or damage is caused by the Company’s negligence or fault. Some states do not allow the
and service during the three year period commencing with the date of manufacture.
exclusion or limitation of incidental or consequential damages, so the above limitation
After phoning System Sensor’s toll free number 800-SENSOR2 (736-7672) for a Return
or exclusion may not apply to you. This Warranty gives you specific legal rights, and you
Authorization number, send defective units postage prepaid to: System Sensor, Repair
may also have other rights which vary from state to state.
FCC Statement
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must
accept any interference received, including interference that may cause undesired operation.
Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used
in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to
try to correct the interference by one or more of the following measures:

– Reorient or relocate the receiving antenna.

– Increase the separation between the equipment and receiver.

– Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.

– Consult the dealer or an experienced radio/TV technician for help.



©2011 System Sensor