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A05-228-01

1551B with

6

″ base

2551THR with

4

″ base

1551B

The 1551B Intelligent Ionization Smoke Sensor’s unique

unipolar chamber responds quickly and uniformly to the

broadest range of fires and can withstand wind gusts up to

1500 feet-per-minute without outputting an alarm level

signal. Because of the unipolar chamber, the 1551B is

more responsive than most ionization sensors. This makes

it a more stable detector.

Specifications – 1551B

Dimensions

Height:

2.3

″ (5.8 cm), detector in base

Diameter:

4.0

″ (10.2 cm)

installed in B501 base

6.1

″ (15.5 cm)

installed in B501B base

Shipping Weight:

9.5 ounces (269 g)

Temperature Range:

32

° to 120°F (0° to 49°C)

Humidity Range:

10% to 93% RH noncondensing

Air Velocity Rating:

1,500 fpm

Operating Voltage:

15–32 VDC peak, 6.5 mA

current for visible LEDs

latched on

Standby Current:

200

µA

Sensor:

Unipolar, dual chamber

Smoke Detector Spacing:

On smooth ceilings (as defined in NFPA 72) spacing of

30 feet (900 sq. ft.) may be used as a guide. See NFPA

72 for more details on spacing requirements.

2551HR/2551THR

The 2551HR Intelligent Photoelectronic Sensor represents

the state of the art in smoke sensor technology. It features

fully coated circuit boards, special insect and dirt

protection and superior RF/transient protection. The

sensor will transmit an analog value representative of the

sensitivity that can be used by the system to determine

when maintenance is required. Signal processing for alarm

verification can be built into the system to provide

immunity to false alarms.

The 2551THR Intelligent Photoelectronic Sensor adds a

thermal heat collector that will alarm at a fixed

temperature of 135

°F.

General Description

All 500 Series sensors are simple to install, service, and

maintain. Using a specially designed tool (XR5),

maintenance personnel can easily remove and replace the

plug-in detectors without using a ladder. 500 Series

sensors incorporate built-in identification allowing the

system to identify the type of sensor. They also have a

built-in magnetic reed switch for local testing, and the

1551B, 2551HR, and 2551THR can be sensitivity tested

with the MOD400R Field Sensitivity Test Tool.