System Sensor 2251TB is a plug-in intelligent photoelectric smoke sensor with a built-in 135°F (57.2°C) fixed temperature heat detector. It combines a photoelectronic sensing chamber with addressable-analog communication, sending an analog representation of smoke density to a compatible control panel. This model is discontinued.
Rotary decade switches set the sensor address, and two LEDs controlled by the panel show sensor status. An output is provided for an optional RA400Z remote LED annunciator. The sensor includes a tamper-resistant feature that prevents removal from the base without a tool.
Specifications
| Sensing |
Photoelectric smoke plus 135°F fixed temperature thermistor |
| Operating voltage |
15 to 32 VDC |
| Standby current |
300 µA at 24 VDC (one communication every 5 seconds, LED blink enabled) |
| Maximum alarm current |
6.5 mA at 24 VDC (LED on) |
| Operating temperature |
32°F to 100°F (0°C to 38°C) |
| Humidity |
10% to 93% RH, non-condensing |
| Height |
2.0 in. (51 mm) installed in B210LP base |
| Diameter |
6.1 in. (155 mm) in B210LP base; 4.1 in. (104 mm) in B501 base |
| Weight |
5.2 oz (147 g) |
Installation notes
- Base is supplied separately; wire the base, set the address, then twist the sensor into the base clockwise
- Connect only to compatible addressable control panels
- Suitable for use in ducts (pendant mount per Duct Applications Guide A05-1004), not inside duct smoke detector housings
- Remove the dust cover before the sensor is put into service
- Functional test with a test magnet (M02-04-01 or M02-09-00); smoke entry test with aerosol
Related models
- 2251B: photoelectric sensor without heat detector
- 2251TMB: photoelectric sensor with 135°F heat detector
Documents
FAQ
Is a base included?
No. The 2251TB is a plug-in sensor; the base is supplied separately. It is dimensioned for the B210LP and B501 bases.
How is the address set?
With the rotary decade address switches (tens and ones) on the sensor.
Can it be used in a duct?
The 2251TB is suitable for use in ducts (see System Sensor Duct Applications Guide A05-1004 for pendant mounting), but not inside duct smoke detector housings.
What is the operating temperature range?
32°F to 100°F (0°C to 38°C), narrower than the 2251B photo-only sensor.
