System Sensor 2WTA-B, 2WTR-B, 4WTA-B, 4WTR-B Install Guide

I56-2170-008R

INSTALLATION AND MAINTENANCE INSTRUCTIONS

Series

Photoelectric Smoke Detector
2-Wire:
4-Wire:

2WTR-B (Form C Relay), 2WTA-B (Sounder)
4WTR-B (Form C Relay), 4WTA-B (Sounder)
4WTAR-B (Form C Relay, Sounder), 4WITAR-B (Isolated Thermal, Form C Relay, Sounder)

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

Electrical Specifications
System Voltage –Nominal:
Min.:
Max.:
Max. Ripple Voltage:
Avg. Standby Current:
Peak Standby Current:
Max. Alarm Current
4WTA-B, 4WTR-B:
4WTAR-B, 4WITAR-B:
2WTR-B:
2WTA-B:
Alarm Contact Ratings:
Form C Contact Ratings:
Audible Signal
(temp-3 tone):
Remote Annunciator Output:
EOL Relay:
Reset Time (min):
Max. Start-up Capacitance:
Max. Initial Start-up Time:
AlarmVerification**
Start-up Time:

2-wire
12/24

8.5
35
30
50
100

4-wire
12/24
V
(Non-polarized for 2WTR-B and 4WTR-B)
10
V
35
V
30
% peak to peak of applied voltage
50
µA average
—
µA

—
—
130
130*
—
2

35
50
—

mA
mA
mA panel must limit current

0.5
2

A @ 30 V AC/DC
A @ 30 V AC/DC

85
7
—
2-wire
0.3
0.1
45

85
—
12/24
4-wire
0.3
—
15

dBA min. in alarm or supply polarity reversed (Sounder units only)
mA maximum
A77-716B

15

15

seconds

seconds
µF
seconds

*Direct Power (Non-reverse Polarity): 130 mA limited by panel.
Reverse Polarity Power: 30 mA for the 2WTA-B in alarm; 12 mA for all other 2WTA-B units on the loop. Add 25 mA for the RRS-MOD reversing relay alarm current.
**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:
Freeze Trouble:
Operating Temperature Range:
Operating Humidity Range:
Storage Temperature Range:
Diameter (including base):
Height (including base):
Weight:

135°F (57.2°C)
41°F (5°C)
32 to 100°F (0 to 37.8°C)
0 to 95%
RH non-condensing
–4 to 158°F (–20 to 70°C)
5.3 inches
2.0 inches
7.1 oz.

Before Installing
Please read thoroughly System Sensor Applications Guide for System Smoke
Detectors, which provides detailed information on detector spacing, placement, zoning, wiring, and special applications. Copies are available on System
Sensor’s web site: www.systemsensor.com.

Models 2WTA-B, 4WTA-B, 4WTAR-B, and 4WITAR-B contain a piezoelectric
horn which generates the ANSI S3.41 temporal pattern in an alarm condition.
All detectors on a zone will sound when the power supply to them is reversed.
The RRS-MOD can be used for the power supply reversal function. The RRSMOD also enables all the detectors’ sounders on a zone to be synchronized
and allows the zone to be silenced from the panel by entering the alarm silence key at the keypad.

NOTICE: This manual shall be left with the owner/user of this equipment.
IMPORTANT: This detector must be tested and maintained regularly following National Fire Protection Association (NFPA) 72 National Fire Alarm Code
requirements. At a minimum, cleaning should be performed annually.
General Description
Models 2WTR-B and 2WTA-B are 2-wire photoelectric smoke detectors; models
4WTR-B, 4WTA-B, 4WTAR-B, and 4WITAR-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. All models 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.
D100-99-00

The detector that initiated the alarm condition will have its red LED and Form
C relays (if applicable) latched until reset by panel.
The model 4WITAR-B photoelectronic smoke sensor is isolated from the fixedtemperature heat sensor, providing a self-resetting, local audible smoke alarm
that does not alarm at the panel. Only the fixed-temperature heat sensor will
cause the 4WITAR-B to initiate an alarm at the panel and the relay to change
its state.
NOTE: In order for all i3 sounder detectors on a loop to sound when the panel
alarms, the supply voltage polarity must be reversed. A reversing relay, System
Sensor model number RRS-MOD, must be used. The RRS-MOD is designed
to allow all i3 Series detectors in the same loop to sound when one of the
detectors goes into alarm. In addition, the RRS-MOD will synchronize all of
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I56-2170-008R

Each i3 Series detector is supplied with a mounting base that can be ceiling- or
wall-mounted:

the i3 Series sounder smoke detectors on the loop. Some panels may require
the use of programmable outputs. Refer to System Sensor literature for further
information on the RRS-MOD.
All i3 Series detectors are designed to provide open area protection. Two-wire models
must be used with compatible UL Listed panels only.

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 1: Mounting of Detector

When used with an “i3 Ready” control panel or the i3 Series 2W-MOD2 module (refer to installation manual), the 2WTR-B and 2WTA-B are capable of
generating a “maintenance needed” signal. The 2W-MOD2 can indicate a need
for cleaning, replacement, or a freeze trouble at the control panel or module.
WARNING

The 2W-MOD2 has replaced the previous model number 2W-MOD. To ensure
proper remote maintenance signaling capabilities, do not use the 2W-MOD
with i3 model numbers 2WTR-B and 2WTA-B.

S0121-00

Installation of the 2WTR-B, 2WTA-B, 4WTR-B, 4WTA-B, 4WTAR-B, and
4WITAR-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 fasteners.

The i3 Series heads and bases are keyed so that all heads will only fit into
their respective bases. One model 4-wire relay base will accept the 4WTR-B,
4WTAR-B and 4WITAR-B detector heads and no others. The 2WTR-B, 2WTA-B
and 4WTA-B will only fit into their respective mounting bases and no others.
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,
and the test switch is aligned with the tamper release tab.

Two LEDs on the detector provide a local visual indication of the detector’s status:
Table 1: Detector LED Modes
Power-up
Normal (standby)
Out of sensitivity
Freeze Trouble
Alarm

Green LED
Blink 10 sec
Blink 5 sec
—
—
—

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.

Red LED
Blink 10 sec
—
Blink 5 sec
Blink 10 sec
Solid

During 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).

Installation Guidelines
The i3 Series detectors represent an advancement over the previous sounder
and Form C relay models and are designed to be used with the 2W-MOD2 and
RRS-MOD only. Do not mix detector models on a zone.

Table 2: Power-up Sequence for LED Status Indication*

Figure 2: Tamper-Resistant Feature

Condition
Initial LED Status Indication
Initial LED Status Indication

SNAP OFF TAB FOR
TAMPER LOCK

Duration
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).
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).

TAMPER RELEASE TAB

S0109-00

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.
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.

To measure the detector’s sensitivity, the i3 Series Model SENS-RDR Infrared
Sensitivity Reader tool (see Figure 4) should be used. Refer to instructions
manual D100-98-00 for the proper use of the SENS-RDR.
Models 2WTR-B and 2WTA-B also include an output that allows an optional
Model RA400Z/RA100Z Remote Annunciator to be connected.

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. Do not put wires more than 2
gauge apart under the same clamping plate.

Mounting
General spacing guidelines are 30˝×30˝, with each detector covering 900 ft2
under maximum conditions.

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 2WTR-B and 2WTA-B, connect detectors only to compatible alarm control
panels as identified by System Sensor’s two-wire compatibility chart, available
at www.systemsensor.com.

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

D100-99-00

DIRECT MOUNT HOLES

Wiring Installation Guidelines
All wiring must be installed in compliance with the NFPA 70, National Electrical Code, applicable state and local codes, and any special requirements of the
local Authority Having Jurisdiction.

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I56-2170-008R

NOTE: Models 2WTR-B and 2WTA-B are not to be installed on initiating circuits containing other makes/models of smoke detectors.
NOTE: Style D initiating circuits require the use of a 2W-MOD2 for models
2WTR-B and 2WTA-B.
Wiring Diagrams
Figure 3a: Wiring Diagram, 2WTR-B and 2WTA-B

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
applicable.
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 unit.
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.

EOL
RESISTOR

2-WIRE
ZONE

RA400Z

(5) RA –

(6) NC

(4) RA +

(7) C

(3) – IN/OUT

–

(8) NO

(2) + OUT

OPTIONAL
RELEASING
DEVICE

CAUTION

(1) + IN

+
2-WIRE
CONTROL
PANEL

Dust covers are an effective way to limit the entry of dust into the smoke
detector sensing chamber during construction. 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.

NOT INCLUDED ON
2WTA-B MODEL

S0122-00

NOTE: FOR ALL COMPATIBLE ADEMCO PANELS,
DO NOT EXCEED 30 OHMS LINE IMPEDANCE.
NOTE: ONLY ONE 2WTR-B DETECTOR PER ZONE CAN BE USED.
NOTE: Only one 2WTA-B detector shall be installed on a zone, unless the
panel switches the zone to a reverse polarity, non-current limited power supply. For panels that do not provide this feature, a reversing relay, System Sensor model RRS-MOD, may be used. When utilized with the 2WTA-B, it allows
for more than one detector to be utilized on a loop. Some panels may require
the use of programmable outputs. Refer to System Sensor literature for further
information on the RRS-MOD. The 2WTA-B detector shall not be mixed with
other 2-wire detectors on the same zone.

CAUTION

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

When using the RRS-MOD with model 2WTA-B, do not mix the 2WTA-B with
other model smoke detectors and dry contact closure devices, including mechanical heat detectors, manual pull stations and waterflow switches. Such
mixing can cause a direct short on the auxiliary power terminals, damaging
the control panel’s internal circuitry and/or damage devices connected to the
initiating device circuit.

CAUTION

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 www.systemsensor.com.

Testing
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.

Figure 3b: Wiring Diagram, 4WTR-B, 4WTA-B, 4WTAR-B, and
4WITAR-B
AUX OR +
SMOKE
POWER –

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 one second.

EOL
RELAY
(A77-716B)

–
IDC +
EOL
RESISTOR

(5) A

(6) NC
(7) C

(8) NO

(6) NC
(7) C

(8) NO

OPTIONAL
RELEASING
DEVICE

(4) A

(3) – IN/OUT

(2) + OUT

(1) + IN

(5) A

(4) A

(3) – IN/OUT

NOT INCLUDED ON
4WTA-B MODEL

(2) + OUT

(1) + IN

4-WIRE
CONTROL
PANEL

Figure 4: Recessed Test Switch Opening and SENS-RDR Position
POSITION SENS-RDR AT AN ANGLE ON
THE OVAL AREA OR AT THE CHAMBER
OPENING BY THE WORD “PAINT”

NOT INCLUDED ON
4WTA-B MODEL

OPTIONAL
RELEASING
DEVICE

LED

S0123-00

Installation

RECESSED
TEST SWITCH

WARNING

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

D100-99-00

PUSH RECESSED
SWITCH WITH A
0.18″ MAX.
DIAMETER TOOL

S0110-00

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.

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I56-2170-008R

C. Direct Heat Method
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.

Maintenance
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 5.)
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.

NOTE: For the above tests, the detector will reset only after the power source
has been momentarily interrupted. It is not necessary to reset the model
4WITAR-B, when smoke is used to initiate the alarm.
When testing the 4WITAR-B model, pressing the test switch will result in a
non-latching local alarm that does not alarm at the control panel. Once the
test button is released, the unit will return to its standby condition. Only the
fixed-temperature heat sensor will cause the 4WITAR-B to initiate an alarm at
the panel.
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.
Notify the proper authorities when the system is back in service.
Loop Verification (models 2WTR-B and 2WTA-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-MOD2
module only. The EZ Walk loop test verifies the initiating loop wiring and
provides visual status indication at each detector. Refer to System Sensor literature for further information on the 2W-MOD2.

Figure 5: Removing Screen/Sensing Chamber
REMOVABLE
DETECTOR
COVER

SCREEN/SENSING
CHAMBER
(TOP HALF)

WARNING

The 2W-MOD2 has replaced the previous model number 2W-MOD. To ensure
proper EZ Walk Test capabilities, do not use the 2W-MOD with i3 model numbers 2WTR-B and 2WTA-B.
Table 3: EZ Walk Test Detector Modes

Proper Operation
Out of Sensitivity
Freeze Condition

Green LED
Double blink 5 sec
—
—

S0111-00

DETECTOR HOUSING

Red LED
—
Double Blink 5 sec
Double Blink 10 sec

NOTE: The EZ Walk loop test must not be used instead of alarm testing.

Please refer to insert for the Limitations of Fire Alarm Systems
Three-Year Limited Warranty
System Sensor warrants its enclosed product to be free from defects in materials and
#__________, 3825 Ohio Avenue, St. Charles, IL 60174. Please include a note describing
workmanship under normal use and service for a period of three years from date of
the malfunction and suspected cause of failure. The Company shall not be obligated to
manufacture. System Sensor makes no other express warranty for the enclosed product.
replace units which are found to be defective because of damage, unreasonable use,
No agent, representative, dealer, or employee of the Company has the authority to inmodifications, or alterations occurring after the date of manufacture. In no case shall the
crease or alter the obligations or limitations of this Warranty. The Company’s obligation
Company be liable for any consequential or incidental damages for breach of this or any
of this Warranty shall be limited to the replacement of any part of the product which
other Warranty, expressed or implied whatsoever, even if the loss or damage is caused by
is found to be defective in materials or workmanship under normal use and service
the Company’s negligence or fault. Some states do not allow the exclusion or limitation of
during the three year period commencing with the date of manufacture. After phoning
incidental or consequential damages, so the above limitation or exclusion may not apply
System Sensor’s toll free number 800-SENSOR2 (736-7672) for a Return Authorization
to you. This Warranty gives you specific legal rights, and you may also have other rights
number, send defective units postage prepaid to: System Sensor, Returns Department, RA
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.

D100-99-00

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I56-2170-008R
©2009 System Sensor