3825 Ohio Avenue • St. Charles, IL 60174

Phone: 800-SENSOR2 • Fax: 630-377-6495

©2006 System Sensor.

Product specifications subject to change without notice. Visit systemsensor.com for

current product information, including the latest version of this data sheet.

A05-0348-003 • 7/06 • #1676

Ordering Information

Model

Thermal

Wiring

Alarm Current

2WTA-B

Yes

2-wire

130 mA max. limited by

control panel

2WTR-B

Yes

2-wire

130 mA max. limited by

control panel

4WTA-B

Yes

4-wire

35 mA

4WTR-B

Yes

4-wire

35 mA

4WTAR-B

Yes

4-wire

50 mA

4WITAR-B

Yes

4-wire

50 mA

Smoke Detector Specifications

Electrical Specifications

Operating Voltage

Nominal: 12/24 V non-polarized

2-wire: 8.5 V - 35 V

4-wire: 10 V - 35 V

Maximum Ripple Voltage

30% of applied voltage (peak to peak)

Standby Current

2-wire: 50 µA maximum average

4-wire: 50 µA maximum average

Peak Standby Current

2-wire: 100 µA

4-wire: n/a

Maximum Alarm Current

2-wire: 2WTR-B: 130 mA limited by control

panel

2WTA-B: 130 mA**

4-wire: 4WTA-B, 4WTR-B: 35 mA

4WTAR-B, 4WITAR-B: 50 mA

**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.

Alarm Contact Ratings

2-wire: n/a

4-wire: 0.5 A @ 30V AC/DC

Form C Contact Ratings

2A @ 30V AC/DC

Physical Specifications

Operating Temperature

Range

32°F–100° F (0°C–37.8° C)

Operating Humidity

Range

0 to 95% RH non-condensing

Thermal Sensor

135° F (57.2° C) fixed

Freeze Trouble

41° F (5° C)

Sensitivity

2.5%/ft. nominal

Input Terminals

14–22 AWG

Dimensions (including

base)

5.3 inches (134 mm) diameter, 2.0 inches (51

mm) height

Approximate Weight

7.1 oz. (200 grams)

Sound Pressure Output

85 dBA (models 2WTA-B, 4WTA-B, 4WTAR-B,

and 4WITAR-B only)

Mounting

3½-inch octagonal back box, 4-inch octagonal

back box, Single gang back box, 4-inch square

back box with a plaster ring, Direct mount to

ceiling

LED Modes

LED Mode

Green LED

Red LED

Condition

Duration

Power up

Blink every

10 seconds

Blink every 10

seconds

Initial LED

status

indication

80 seconds

Normal

(standby)

Blink every 5

seconds

off

Out of

sensitivity

off

Blink every 5

seconds

Freeze

trouble

off

Blink every 10

seconds

Alarm

off

Solid

Power Up Sequence for LED Indication

Condition

Duration

Initial LED

status

indication

80 seconds

Architect/Engineer Specifications

Smoke detector shall be a System Sensor i3 Series model number_______,

listed to Underwriters Laboratories UL 268 for Fire Protection Signaling

Systems. The detector shall be a combination photoelectric/thermal

equipped with a sounder (model 2WTA-B, 4WTA-B), a Form C relay (model

2WTR-B), a combination sounder/relay (model 4WTAR-B) or an isolated

thermal/sounder/relay (model 4WITAR-B). The detector shall include a

mounting base for mounting to 3½-inch and 4-inch octagonal, single gang,

and 4-inch square back boxes with a plaster ring, or direct mount to the

ceiling using drywall anchors. Wiring connections shall be made by means

of SEMS screws. The detector shall allow pre-wiring of the base and the

head shall be a plug-in type. The detector shall have a nominal sensitivity

of 2.5% per foot nominal as measured in the UL smoke box. The detector

shall be capable of automatically adjusting its sensitivity by means of drift

compensation and smoothing algorithms. The detector shall provide dual

color LED indication which blinks to indicate power-up, normal standby, out

of sensitivity, alarm, and freeze trouble conditions. When used in conjunction

with the 2W-MOD2 module, 2-wire models shall include a maintenance

signal to indicate the need for maintenance at the alarm control panel, and

shall provide a loop testing capability to verify the circuit without testing each

detector individually. When used in conjunction with the RRS-MOD module,

synchronized, and all sounders may be silenced from the panel.

Model

Description

RRS-MOD

Reversing relay/synchronization module

2W-MOD2

2-wire loop test/maintenance module

SENS-RDR

Sensitivity reader

RT

Removal/replacement tool

A77-AB2

Retrofit adapter bracket