System Sensor 2151 User Manual
System Sensor Safety

D100-04-00
1
I56-581-07R
2151 Low Profile
Photoelectronic Plug-in 
Smoke Detector
INSTALLATION AND MAINTENANCE INSTRUCTIONS
3825 Ohio Avenue, St. Charles, Illinois 60174
1-800-SENSOR2, FAX: 630-377-6495
www.systemsensor.com
Before Installing 
Please	 thoroughly	 read	 the	 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.	
NOTICE:	This	manual	should	be	left	with	the	owner/user	
of	this	equipment.
IMPORTANT: The	 detector	 used	 with	 this	 base	 must	 be	
tested	and	maintained	regularly	following	NFPA	72	require-
ments.	The	detector	used	with	this	base	should	be	cleaned	
at	least	once	a	year.
General Description
The	2151	low-profile	photoelectronic	detector	uses	a	state-
of-the-art	optical	sensing	chamber.	This	detector	is	designed	
to	provide	open	area	protection	and	to	be	used	with	com-
patible	UL	listed	control	panels	only.	The	capability	of	plug-
ging	 this	 detector	 into	 a	 variety	 of	 special	 bases	 makes	 it	
more	versatile	than	equivalent	direct-wired	models.
Two	 LEDs	 on	 each	 detector	 provide	 local	 360°	 visible	
alarm	indication.	They	flash	every	ten	seconds	indicating	
that	power	is	applied	and	the	detector	is	working	properly.	
The	 LEDs	 latch	 on	 in	 alarm.	 Remote	 LED	 annunciator	
capability	 is	 standard	 and	 may	 be	 implemented	 through	
an	 optional	 accessory	 RA400Z.	 The	 alarm	 can	 be	 reset	
only	 by	 a	 momentary	 power	 interruption.	 This	 detector	
may	be	tested	by	activating	the	internal	reed	switch	with	
a	magnet.
Base Selection And Wiring Guide
Refer	 to	 the	 installation	 instructions	 for	 the	 Plug-in	
Detector	Bases	for	base	selection	and	wiring	instructions.	
System	Sensor	has	a	variety	of	detector	bases	available	for	
Specifications
Size	
Height:	
1.7 inches (43 mm)
Diameter:
4.0 inches (101 mm)
Weight:
3.6 oz. (102 g)
Operating Temperature Range:
0°C to 49°C (32°F to 120°F)
Operating Humidity Range:
10% to 93% Relative Humidity noncondensing
Latching Alarm:
Reset by momentary power interruption.
this	smoke	detector,	including	2-wire	applications	with	and	
without	relays	and/or	current	limiting	resistors,	4-wire	and	
120VAC	applications.
All	 bases	 are	 provided	 with	 screw	 terminals	 for	 power,	
ground,	remote	annunciator	connections	and	relay	contact	
connections,	 if	 applicable.	 The	 electrical	 ratings	 for	 each	
detector-base	 combination	 are	 also	 included	 in	 the	 base	
installation	instructions.
Installation
NOTE:	 All	wiring	must	conform	to	applicable	local	codes,	
ordinances, and regulations.
NOTE: Verify that all detector bases are installed, that
the	initiating-device	circuits	have	been	tested,	and	
that	 the	 wiring	 is	 correct.	 (Refer	 to	 detector	 base	
manual	for	testing	procedure.)
WARNING
Remove	power	from	initiating-device	circuits	before	install-
ing	detectors.
1.	Install	detectors:
	 a.	 Place	the	detector	into	the	detector	base.
	 b.	Turn	 the	 detector	 clockwise	 until	 the	 detector	 drops	
into place.
c. Continue turning detector clockwise to lock it in
place.
2. Tamper Resistance: The detector bases can be made tam-
per	resistant.	When	capability	is	enabled,	detectors	can-
not	be	removed	from	the	base	without	the	use	of	a	tool.	
See	the	detector	base	installation	manual	of	the	detector	
base	for	details	in	using	this	capability.
3. After all detectors have been installed, apply power to
the control unit.
