• Low profile, 1.8" high (with base)
• 2 or 4 wire base compatibility, relay bases available
• Highly stable operation, RF/Transient protection
• Low standby current, 45μA at 24VDC
• Two built-in power/sensitivity supervision/alarm LEDs
• Non-directional smoke chamber
• Vandal resistant security locking feature
• Built-in magnetic go/no go detector test feature
• Removable smoke labyrinth for cleaning or
• Automatic Sensitivity window verification function
meets outlined requirements in NFPA 72, Chapter 2
& 7, Inspection, Testing and Maintenance
• Compatible with SIJ-24 ionization detectors
• Backwards compatible with Hochiki SLK and
Light Source GaAlAs Infrared
Rated Voltage 17.7 - 30.0 VDC
Working Voltage 15.0 - 33.0 VDC
Maximum Voltage 42 VDC
Supervisory Current 45μA @ 24 VDC
Surge Current 160μA max. @ 24VDC
Alarm Current 150mA max. @ 24 VDC
Air Velocity Range 0-4000 fpm
Ambient Temperature 32°F to 120°F
(0°C to 49°C)
Color & Case Material Bone PC/ABS Blend
Sensitivity Test Feature Automatic Sensitivity
window verification test
Mounting Refer to NS Conventional
Detector Base Data Sheet
The SLR-24V can be used in all areas where Photoelectric
Smoke Detectors are required. The wide range
smoke chamber makes the SLR-24V well suited for fires
ranging from smoldering to flaming fires.
NS-4 Series, NS-6 Series, HSC-4R or HSC-xxx R Style
bases may be used with the SLR-24V. Current
interchangeable/compatible devices are the SIJ-24
ionization detector, the SLR-24H photoelectric detector
with heat sensor, and the DCD-135/190 heat detectors.
All NS conventional devices are mechanically
compatible with Hochiki America HSB, HSC and YBA
type bases which may have been used in previous
installations. Please check individual panel listings for
The SLR-24V photoelectric smoke detector utilizes two
bicolored LEDs for indication of status. In a normal
standby condition the LEDs flash Green every 3 seconds.
When the detector senses that its sensitivity has
drifted outside the UL listed sensitivity window the LEDs
will flash Red every 3 seconds. When the detector
senses smoke and goes into alarm the status LEDs will
latch on Red.
The detector utilizes an infrared LED light source and
silicon photo diode receiving element in the smoke chamber.
In a normal standby condition, the receiving element
receives no light from the pulsing LED light source.
In the event of a fire, smoke enters the detector smoke
chamber and light is reflected from the smoke particles
to the receiving element. The light received is converted
into an electronic signal.
Signals are processed and compared to a reference level,
and when two consecutive signals exceeding the reference
level are received within a specified period of time,
the time delay circuit triggers the SCR switch to activate
the alarm signal. The status LEDs light continuously
during the alarm period.