Gentex 7139CS/CSX & 7139LS User Manual

The 7139CS/CSX & 7139LS Smoke Alarms are

Photoelectric Type Alarms for use as an evacuation device in

residential applications, while the 7109CS/CSX & 7109LS are
for use as an alert and relocate device.  Each alarm has a solid
state piezo signal to warn and alert the household to the 

presence of threatening smoke.

Your Photoelectric alarm is designed to detect the smoke

that results from an actual fire.  Consequently, it is uncommon

for household smoke such as cigarette smoke or normal 
cooking smoke to cause an alarm.

7109CS/CSX-W or C*.....120 VAC, 60 Hz with 1 Form C 

Aux. Relay Contact and Visual 
Signaling Strobe Light with Tandem 
Wire Connection.  CSX model is 

provided with an additional wire (grey) 
for the remote activation of the strobe.

7109LS*..........................120 VAC, 60 Hz Wall Mounted, 

Provided With a 9 ft. Line Cord, 
Pulsating Horn.

7139CS/CSX-W or C......Same as the 7109CS but with a 

Temporal Horn.  CSX model is 
provided with an additional wire (grey) 
for the remote activation of the strobe.

7139LS...........................Same as 7109LS but with a 

Temporal Horn.

These Smoke Alarms operate on the photoelectric light

scatter principle.  The unit's sensing chamber houses a light

source and a light sensor.

The darkened sensing chamber is exposed to the 

atmosphere and designed to permit optimum smoke entry from

any direction while rejecting light from outside the alarm.

The light source is an infrared (invisible) LED which pulses

every 4-8 seconds.  The light sensor is a photodiode matched

to the light frequency of the LED light source.

Under normal conditions, the light generated by the pulsing

infrared LED is not seen by the light sensor, as it is positioned
out of the direct path of the light beam.  When smoke enters
the sensing chamber, light from the pulsing LED light source is

reflected by the smoke particles onto the photodiode light sen-
sor.  At the first sighting of smoke, the alarm is put into a pre-
alarm mode.  

This is indicated by a rapidly flashing LED on the face of the

alarm.  Once the light sensor confirms smoke for 2 consecutive
pulses inside the chamber, the light sensor produces the signal
necessary to trigger the alarm.

This technique of verifying the smoke condition, combined

with a 5-to-1 signal-to-noise ratio, substantially reduces the
possibility of nuisance alarms.

§ Your alarm is provided with an alarm horn and pulsating 

Light Emitting (indicator) Diode, which pulses every 15-30 

seconds, and a green AC power on LED.

§ When turning the test knob on the alarm to TEST 1, the red 

light will flash rapidly, the horn will sound and the strobe will 

flash.  Strobe will not operate without AC power.

§ If the battery is low, a chirp will be sounded when the red 

LED flashes.  If the alarm is malfunctioning, or if the battery 

is missing, the chirp is sounded without the red LED flashing.   
If AC power fails, the green LED will turn off. 

§ The test knob of your alarm simulates actual smoke 

conditions.

NOTE: Tandem Interconnect Models.

§ When testing one alarm, the alarm that is activated will 

flash the red indicator light emitting diode and sound its 

alarm horn.  All other units will sound the alarm horn with 
their red indicator lights remaining off.

This Smoke Alarm can quickly alert you to the presence of

smoke-it cannot prevent fire.  Please note that there are 
hazards against which smoke detection may not be effective,
such as smoking in bed, explosions, when a closed door 

separates the alarm from the source of the smoke, etc.  The
ultimate responsibility for fire protection rests solely on you.
1.  To minimize fire hazards-avoid improper storage of 

flammable liquids and don't leave small children home 
alone.

2.  Bedroom doors should be closed while sleeping if a 

smoke alarm is installed in the bedroom.  They act as a 
barrier against heat and smoke.

3.  Establish an escape plan:

(a)  Post a detailed floor plan depicting the chosen escape 

routes.

(b)  Each bedroom should have at least two escape routes.

(c)  Make sure your children know what to do in case of 

fire and teach them to follow the escape plan you 
have posted.

(d)  Agree on an outside meeting place.
(e)  Conduct fire drills at least twice a year.
(f)   Be sure each member of the family is familiar with 

the smoke alarm so they can react properly.

If the alarm should sound:
1.  Never waste time dressing or gathering valuables.  Follow 

the escape route and leave the house immediately.

2.  Check bedroom doors before opening.  If the door is hot 

or smoke is leaking in around the edges-DO NOT OPEN-

use the alternate escape route.

Pg. 7-1