First Alert SCO500A User Manual Download Page 1

Printed in Mexico
M08-0146-012    J1
11/10

FIRE SAFETY TIPS

Follow safety rules and prevent hazardous situations: 1) Use smoking 
materials properly. Never smoke in bed. 2) Keep matches or lighters
away from children; 3) Store flammable materials in proper containers;
4) Keep electrical appliances in good condition and don’t overload 
electrical circuits; 5) Keep stoves, barbecue grills, fireplaces and 
chimneys grease- and debris-free; 6) Never leave anything cooking 
on the stove unattended; 7) Keep portable heaters and open flames, like
candles, away from flammable materials; 8) Don’t let rubbish 
accumulate.

Keep alarms clean, and test them weekly. Replace alarms immediately 
if they are not working properly. Smoke Alarms that do not work cannot
alert you to a fire. Keep at least one working fire extinguisher on every
floor, and an additional one in the kitchen. Have fire escape ladders or
other reliable means of escape from an upper floor in case stairs are
blocked.

BASIC SAFETY INFORMATION

• Dangers, Warnings, and Cautions alert you to important 

operating instructions or to potentially hazardous situations. Pay
special attention to these items.

• This Smoke/CO Alarm is approved for use in single-family 

residences.

• This combination Smoke/Carbon Monoxide Alarm has two sepa-

rate alarms. This carbon monoxide alarming device is designed to
detect carbon monoxide gas from ANY source 
of combustion. It will only indicate the presence of carbon monox-
ide or smoke that reaches the sensors. This Alarm is not designed
to sense gas, heat or flames.

• This Smoke/CO Alarm cannot operate without working 

batteries. Removing the batteries for any reason, or failing to
replace the batteries at the end of their service life, removes your
protection.

• NEVER ignore any alarm. See “If Your Smoke/CO Alarm Sounds”

for more information on how to respond to an alarm. Failure to
respond can result in injury or death.

• The Silence Features are for your convenience only and will not

correct a problem. See "Using the Silence Features" for details.
Always check your home for a potential problem after any alarm.
Failure to do so can result in injury or death.

• Test this Smoke/CO Alarm once a week. If the Alarm ever fails to

test correctly, have it replaced immediately! If the Alarm is not
working properly, it cannot alert you to a problem.

• This product is intended for use in ordinary indoor locations of fam-

ily living units. It is not designed to measure CO levels in compli-
ance with Occupational Safety and Health Administration (OSHA)
commercial or industrial standards. Individuals with medical condi-
tions that may make them more sensitive to carbon monoxide may
consider using warning devices which provide audible and visual
signals for carbon monoxide concentrations under 30 ppm. For
additional 
information on carbon monoxide and your medical condition con-
tact your physician.

ONELINK

®

COMBINATION

SMOKE & CARBON MONOXIDE ALARM 

WITH PROGRAMMABLE LOCATION

Features:

Separate sensors to detect
smoke and CO; the two 
alarm sensors work 
independently

Visual signals to indicate
alarm levels of smoke or CO

Wireless interconnect

Powered by two “AA”
batteries

Side access drawer for 
easy battery replacement

USER’S MANUAL

WHAT YOU WILL SEE WITH THIS ALARM

Under Normal Operations

Horn: Silent
Power/Smoke LED: Flashes Green once a minute
CO LED: Off

When You Test the Alarm

Horn: Continuous beeping
Smoke LED: Flashes Red in sync with the horn pattern
Horn: 4 fast beeps, pause, 4 fast beeps
CO LED: Flashes Red in sync with the horn pattern

If Battery Becomes Low or is Missing

Horn: chirps once a minute
Power/Smoke LED: Flashes Green On for 2 seconds/Off for 

2 seconds. Low Battery Latch is now engaged.

CO LED: Off

If Alarm is Not Operating Properly (MALFUNCTION SIGNAL)

Horn: 3 chirps every minute
Power/Smoke LED: 3 Flashes approximately once a minute
CO LED: Off

Alarm has reached its End of Life

Horn: 3 chirps every minute
Power/Smoke LED: 3 Flashes approximately once a minute
CO LED: Off

Alarm Levels of CO are Detected

Horn: 4 beeps, pause, 4 beeps*
Power/Smoke LED: Off
CO LED: During Alarm: Flashes Red in sync with the horn pattern.

After Alarm: Flashes Red On for 2 seconds/Off for 2 
seconds. CO Alarm Latch is now engaged.

*NOTE: If unit goes into CO alarm, the regular 4 beeps-brief pause
cycle will repeat for four minutes. After four minutes, the pause will
increase to one minute.

Smoke is Detected

Horn: Continuous beeping
Power/Smoke LED: During Alarm: Flashes Red in sync with the

horn pattern. After Alarm: Flashes Red On for 2 seconds/
Off for 2 seconds. Smoke Alarm Latch is now engaged.

CO LED: Off

Smoke Alarm is Silenced

Horn: Off
Power/Smoke LED: Flashes Red
CO LED: Off

CO Alarm is Silenced

Horn: Off
Power/Smoke LED: Off
CO LED: Flashes Red

Model

SCO500A

1

INSTALLATION

WHERE TO  INSTALL THIS  ALARM

Minimum coverage for Smoke Alarms, as recommended by the National
Fire Protection Association (NFPA), is one Smoke Alarm on every floor,
in every sleeping area, and in every bedroom (See “Regulatory
Information For Smoke Alarms” for details on the NFPA 
recommendations).

For CO Alarms, the National Fire Protection Association (NFPA) 
recommends that a CO Alarm should be centrally located outside of
each separate sleeping area in the immediate vicinity of the bedrooms.
For added protection, install additional CO Alarms in each separate 
bedroom, and on every level of your home.

NOTE: For added protection, install an additional Smoke/CO Alarm at least 
4.6 meters (15 feet) away from the furnace or fuel burning heat source
where possible. In smaller homes or in manufactured homes where this
distance cannot be maintained, install the Alarm as far away as possible
from the furnace or other fuel burning source. Installing the Alarm closer
than 15 feet (4.6 meters) will not harm the Alarm, but may increase the 
frequency of unwanted alarms.

In general, install combination Smoke and Carbon Monoxide Alarms:

In the hall near every sleeping area. If your home has multiple 
sleeping areas, install a unit in each. If a hall is more than 12 meters
(40 feet) long, install a unit at each end.

On every level of your home, including finished attics and basements.

Inside every bedroom, especially if people sleep with the door partly
or completely closed.

At the top of first-to-second floor stairs.

At the bottom of the basement stairs.

For additional coverage, install Alarms in all rooms, halls, and 
storage areas, where temperatures normally remain between 4.4

O

C

and 37.8

O

C (40

O

F and 100

O

F).

Recommended Placement

When installing on the wall, the top edge of Smoke Alarms should
be placed between 102 mm (4 inches) and 305 mm (12 inches)
from the wall/ceiling line.

When installing on the ceiling, place the Alarm as close to the center
as possible.

In either case, install at least 102 mm (4 inches) from where the 
wall and ceiling meet. See “Avoiding Dead Air Spaces” for more
information.

NOTE: For any location, make sure no door or other obstruction could
keep carbon monoxide or smoke from reaching the Alarm.

Installing Smoke/CO Alarms in Mobile Homes

For minimum security install one Smoke/CO Alarm as close to each
sleeping area as possible. For more security, put one unit in each room.
Many older mobile homes (especially those built before 1978) have little
or no insulation. If your mobile home is not well insulated, or if you are
unsure of the amount of insulation, it is important to install units on
inside walls only.

3

2

HOW TO  INSTALL THIS  ALARM

For quick installation instructions see the “Quick and Easy Guide to
Programming Your ONELINK

®

Alarm and Using the Optional Features”.

This combination Smoke/CO Alarm was designed to be mounted on the
ceiling or wall. It is not a tabletop device. You must install this device on
the ceiling or wall as outlined below. Read “Where To Install This Alarm”
before starting.

Tools you will need: pencil, drill with 5mm or 3/16” drill bit, 
Phillips screwdriver, hammer.

• Do not install this unit over an electrical junction box. Air 

currents around junction boxes can prevent smoke from reaching
the sensing chamber and prevent the unit from alarming. Only AC
powered units are intended for installation over junction boxes.

If you want to lock the battery compartment, or lock the Smoke/CO
Alarm to the mounting bracket, please read the “Optional Locking
Features” section in the “Quick and Easy Guide to Programming Your
ONELINK

®

Alarm and Using the Optional Features” attachment before

you begin installation.

1. Hold the mounting bracket against the ceiling (or wall) so the vertical

mounting slot is aligned in the 12 o’clock position and trace around
the inside of the mounting slots (vertical and horizontal mounting).

2. Put the unit where it won’t get covered with dust when you drill the

mounting holes.

3. Using a 5 mm (3/16”) drill bit, drill a hole through the center of the

oval outlines you traced.

4. Insert the plastic screw anchors (in the plastic bag with screws) into

the holes. Tap the screw anchors gently with a hammer, if necessary,
until they are flush with the ceiling or wall.

5. Line the mounting bracket up over the plastic screw anchors.

6. Screw the mounting bracket to the ceiling or wall through the mount-

ing slots using the two screws provided.

7. Attach the Smoke/CO Alarm to the mounting bracket. Line up the

guides on the alarm’s base with the
guides 
on the mounting bracket. When guides
are lined up, turn the base clockwise
(right) until it snaps into place.

NOTE: Once the Alarm is snapped
onto the mounting bracket, you 
can rotate the Alarm to adjust the
alignment.

8. Test the Smoke/CO Alarm.

See “Weekly Testing” for details.

PARTS OF THIS SMOKE/CO ALARM

1

Test/Silence Button

2

Battery Compartment

3

Power/Smoke Alarm LED

4

CO Alarm LED

WIRELESS OPERATION

First Alert

®

ONELINK

®

Technology is the easy, cost-effective way to 

provide your family with whole-home safety. All ONELINK

®

Alarms 

communicate with each other without wires or connectors. When one
Alarm sounds, they all sound. This provides your family with an earlier
warning of potential danger, and gives you more time to react.

The communication distance (range) between any two ONELINK

®

Alarms

is typically 15 meters (50 feet) inside of a home. Some features of a
home, such as the number of floors, number/size of rooms, furniture and
types of building materials used may reduce the range of the Alarms.
Examples include: suspended ceilings, ductwork, large metallic appli-
ances (refrigerators) and metal studs. A feature of ONELINK

®

Alarms is

that they operate as a mesh network. All Alarms will repeat any alarm
signal that is received to all other ONELINK

®

Alarms. Interference from

structural conditions can be overcome by adding additional Alarms to
route the wireless signal around obstructions.

• The range and proper operation of any wireless device will vary

depending on its surroundings. It is very important that each Alarm
is tested individually before and after installation to make sure that
all Alarms respond properly.

• The ONELINK

®

Alarms are not to be used outdoors or to transmit

between buildings. The Alarms will not communicate properly
under these conditions.

• Metal objects and metallic wallpaper may interfere with 

signals from wireless Alarms. Alarms should be tested after
changes to your home such as remodeling, moving furniture, and
with metal doors opened and closed.

Your First Alert

®

ONELINK

®

Smoke/CO Alarm will automatically commu-

nicate both potential fires and carbon monoxide presence with all other
First Alert

®

ONELINK

®

Smoke/CO Alarms.

INDUSTRY CANADA NOTICE: Operation is subject to the following 
two conditions:
(1) This device may not cause harmful interference, and (2) this device
must accept any interference received, including interference that may
cause undesired operation. IC:5882A-5001L

Changes or modifications not expressly approved by BRK Brands, Inc.
could void the user’s authority to operate the equipment.

4

5

6

INTRODUCTION

Thank you for choosing First Alert

®

for your Smoke and Carbon

Monoxide Alarm needs. You have purchased a state-of-the-art Smoke &
Carbon Monoxide Alarm designed to provide you with early warning of a
smoke and/or Carbon Monoxide danger.

Key features include:

Smoke & Carbon Monoxide Combination Alarm.

One alarm protects

against two deadly household threats.

ONELINK

®

Enabled.

Alarm automatically communicates with other

ONELINK

®

enabled alarms when installed.

Spread Spectrum Horn Tone.

Lower and varying horn frequency

makes it easier for elderly with normal age related hearing loss to hear
horn. Sweeps through the 2200 – 3400 Hz range.

RF Interconnect.

Reliable and secure radio frequency communication

between alarms. 915 MHz frequency with 65,000 security codes and 3
channel frequency hopping.

Single Button Test/Silence

eliminates confusion. Depending on what

mode the alarm is in, pushing the button provides different functions
such as testing the alarm, silencing the alarm, re-testing the alarm when
in silence and clearing the Latching features.

Two Silence Features. 

Temporarily silence low battery chirp for up to

eight hours before replacing low battery or silence an unwanted alarm for
several minutes.

Two Latching Features.

Alarm Latch: Easily identifies initiating alarm

even after alarm condition has subsided. Low Battery Latch: Identifies
which unit is in low battery condition.

Perfect Mount System

includes a gasketless base for easy installation

and a mounting bracket that keeps the alarm secure over a wide 
rotation range to allow for perfect alignment.

End of Life Signal.

Provides audible confirmation alarm needs to be

replaced.

© 2010 BRK Brands, Inc. All rights reserved.
Distributed by BRK Brands, Inc.
3901 Liberty Street Road, Aurora, IL 60504-8122
Consumer Affairs: (800) 323-9005   •   www.firstalert.com

All First Alert

®

Smoke Alarms conform to regulatory requirements,

including ULC S531 and are designed to detect particles of 
combustion. Smoke particles of varying number and size are 
produced in all fires.

Ionization technology is generally more sensitive than photoelectric
technology at detecting small particles, which tend to be produced
in greater amounts by flaming fires, which consume combustible

materials rapidly and spread quickly. Sources of these fires may include
paper burning in a wastebasket, or a grease fire in the kitchen.

Photoelectric technology is generally more sensitive than ionization
technology at detecting large particles, which tend to be produced
in greater amounts by smoldering fires, which may smolder for

hours before bursting into flame. Sources of these fires may include cig-
arettes burning in couches or bedding.

For maximum protection, use both types of Smoke Alarms on each level
and in every bedroom of your home.

TO LOCK THE BATTERY COMPARTMENT

Do not lock the battery compartment until you install the 
batteries and test the Alarm.

If the unit does not alarm during 
testing, DO NOT lock the battery 
compartment! Install new batteries and
test again. If the Alarm still does not
alarm, replace it immediately.

1. Using needle-nose pliers, detach 

one locking pin from the mounting
bracket.

2. After batteries are inserted, then

push the locking pin through the 
hole near the battery door latch on
the back of the Alarm.

OPTIONAL LOCKING FEATURES

TO LOCK THE MOUNTING BRACKET

1. Using needle-nose pliers, detach

one locking pin from the mounting
bracket.

2. Insert the locking pin through the

hole on the back of the Alarm as
shown in the diagram.

3. When you attach the Alarm to the

mounting bracket, the locking pin’s
head will fit into a notch on the
bracket.

The optional locking features are designed to prevent unauthorized removal of the batteries or alarm. It is not necessary to activate the locks in single-
family households where unauthorized battery or Alarm removal is not a concern.

These Alarms have two separate locking features: one to lock the battery compartment, and the other to lock the
Alarm to the mounting bracket. You can choose to use either feature independently, or use them both.

Tools you will need: • Needle-nose pliers  • Standard flathead screwdriver.

Both locking features use locking pins, which are molded into the mounting bracket. Depending on which locking
features you use, remove one or both pins from the mounting bracket using needle-nose pliers.

To permanently remove either locking pin, insert a flathead screwdriver between the locking pin and the lock, and
pry the pin out of the lock.

TO UNLOCK THE BATTERY COMPARTMENT

1. Remove the Alarm from the 

mounting bracket. If the unit is
locked to the bracket, see the 
section “To Unlock the Mounting
Bracket.”

2. Insert a flathead screwdriver under

the head of the locking pin, and 
gently pry it out of the battery 
compartment lock. (If you plan to
relock the battery compartment,
save the locking pin.)

3. To relock the battery compartment,

close the battery door and reinsert
locking pin in lock.

4. Reattach the Alarm to the mounting

bracket.

When replacing the batteries, always
test the Alarm before relocking the bat-
tery compartment.

TO UNLOCK THE MOUNTING BRACKET

1. Insert a flathead screwdriver into the

rectangular cut-out on the mounting
bracket nearest to the locking pin.

2. Pry the Alarm away from the bracket

by pushing up on the screwdriver and
turning the Alarm counterclockwise
(left) at the same time.

IF YOUR SMOKE/CO ALARM SOUNDS

WHAT TO DO FIRST–IDENTIFY THE TYPE OF 
ALARM SIGNAL

Refer to previous section “What You Will See With This Alarm”.

AFTER AN ALARM
After the emergency responders arrive, the premises aired out, and 
your CO Alarm remains in its normal condition, you can check what 
the highest carbon monoxide level sensed was:

Action:

1. Press & Hold Test Button, if you would like to clear the highest 

level sensed.

If you would like to keep the highest level in memory, do not 
press anything.

IF THE SMOKE ALARM SOUNDS

RESPONDING TO AN ALARM

If the unit alarms and you are not testing the unit, it is warning you
of a potentially dangerous situation that requires your immediate
attention. NEVER ignore any alarm. Ignoring the alarm may result in
injury or death.

Never remove the batteries from a battery operated Smoke/CO
Alarm to stop an unwanted alarm (caused by cooking smoke, etc.).
Removing batteries disables the alarm so it cannot sense smoke,
and removes your protection. Instead open a window 
or fan the smoke away from the unit. The alarm will reset automati-
cally.

If the unit alarms get everyone out of the house immediately.

WHAT TO DO IN CASE OF FIRE

• Don’t panic; stay calm. Follow your family escape plan.

• Get out of the house as quickly as possible. Don’t stop to get 

dressed or collect anything.

• Feel doors with the back of your hand before opening them.

If a door is cool, open it slowly. Don’t open a hot door. Keep doors
and windows closed, unless you must escape through them.

• Cover your nose and mouth with a cloth (preferably damp).

Take short, shallow breaths.

• Meet at your planned meeting place outside your home, and 

do a head count to make sure everybody got out safely.

• Call the Fire Department as soon as possible from outside.

Give your address, then your name.

• Never go back inside a burning building for any reason.

• Contact your Fire Department for ideas on making your home

safer.

Alarms have various limitations. See "General Limitations of Smoke/CO
Alarms" for details.

USING THE SILENCE FEATURES

Never remove the batteries to quiet an unwanted alarm. Removing the
batteries disables the alarm and removes your protection.

The Silence Feature is intended to temporarily silence the horn while
you identify and correct the problem. Do not use the Silence Feature in
emergency situations. It will not correct a CO problem or extinguish a
fire.

The Silence Feature can temporarily quiet an unwanted alarm for several 
minutes. You can silence this Smoke/CO Alarm by pressing the
Test/Silence button on the alarm cover for at least 3-5 seconds.

After the Test/Silence button is released, the Red LED blinks during the
silence mode.

When the Smoke Alarm
is Silenced

When the CO Alarm
is Silenced

The Smoke Alarm will remain
silent for up to 15 minutes, then
return to normal operation.

If the smoke has not cleared–or
continues to increase–the device
will go back into alarm.

The CO Alarm will remain silent
for up to 4 minutes.

After 4 minutes, if CO levels
remain potentially dangerous the
horn will start sounding again.

STEP BY STEP GUIDE TO PROGRAMMING 
THIS ALARM

NOTE: Steps 1 through 3 need to be completed within two minutes. If
more than two minutes pass, the Green power LED will stop blinking.
Simply open the battery drawer of the second Alarm and repeat steps 1
through 3.

1. Insert the batteries into the

battery drawer of the next
Alarm. DO NOT CLOSE THE
DRAWER.

2. Press and hold the test 

button and then close the
battery drawer.

3. Once you hear the unit chirp,

release the test button.
The Green power LED will start to blink indicating the ONELINK

®

Alarm is waiting for program data from one of the other setup
ONELINK

®

Alarms.

4. Press and hold the test button on the first Alarm, until the second

Alarm chirps and its Green power LED stops blinking. Then release
the test button.

5. If you have purchased the hardwired battery back-up ONELINK

®

Alarm, you can now connect the hardwired Alarm by installing the
three-wire connector on the ceiling to the Alarm.

6. Repeat steps 1-5 for additional ONELINK

®

Alarms.

You have now successfully linked your new ONELINK

®

Alarms.

To add additional Alarms at a later time, follow steps 1 through 5.

ADDING AND LINKING ADDITIONAL ONELINK

®

ALARMS

WHERE THIS ALARM SHOULD NOT BE INSTALLED

Do NOT locate this Smoke/CO Alarm:

In garages, furnace rooms, crawl spaces and unfinished attics. Avoid
extremely dusty, dirty or greasy areas.

Where combustion particles are produced. Combustion particles
form when something burns. Areas to avoid include poorly ventilated
kitchens, garages, and furnace rooms. Keep units at least 6 meters
(20 feet) from the sources of combustion particles (stove, furnace,
water heater, space heater) if possible. In areas where a 6 meter 
(20-foot) distance is not possible – in modular, mobile, or smaller
homes, for example – it is recommended the Smoke Alarm be
placed as far from these fuel-burning sources as possible. The
placement recommendations are intended to keep these Alarms at a
reasonable distance from a fuel-burning source, and thus reduce
“unwanted” alarms. Unwanted alarms can occur if a Smoke Alarm is
placed directly next to a fuel-burning source. Ventilate these areas
as much as possible.

Within 1.5 meters (5 feet) of any cooking appliance. In air streams
near kitchens. Air currents can draw cooking smoke into the smoke
sensor and cause unwanted alarms.

In extremely humid areas. This Alarm should be at least 3 meters 
(10 feet) from a shower, sauna, humidifier, vaporizer, dishwasher,
laundry room, utility room, or other source of high humidity.

In direct sunlight.

In turbulent air, like near ceiling fans or open windows. Blowing air
may prevent CO or smoke from reaching the sensors.

In areas where temperature is colder than 4.4

O

C (40

O

F) or hotter

than 37.8

O

C (100

O

F). These areas include non-airconditioned crawl

spaces, unfinished attics, uninsulated or poorly insulated ceilings,
porches, and garages.

In insect infested areas. Insects can clog the openings to the sensing
chamber.

Less than 305 mm (12 inches) away from fluorescent lights.
Electrical “noise” can interfere with the sensor.

In “dead air” spaces. See “Avoiding Dead Air Spaces”.

AVOIDING DEAD AIR SPACES
“Dead air” spaces may prevent smoke from reaching the Smoke/CO
Alarm. To avoid dead air spaces, follow installation recommendations
below.

On ceilings, install Smoke/CO Alarms as close to the center of the 
ceiling as possible. If this is not possible, install the Smoke/CO Alarm at
least 4 inches (102 mm) from the wall or corner.

For wall mounting (if allowed by building codes), the top edge of
Smoke/CO Alarms should be placed between 102 mm (4 inches) and 
305 mm (12 inches) from the wall/ceiling line, below typical “dead air”
spaces.

On a peaked, gabled, or cathedral ceiling, install first Smoke/CO Alarm
within 0.9 meters (3 feet) of the peak of the ceiling, measured 
horizontally. Additional Smoke/CO Alarms may be required depending
on the length, angle, etc. of the ceiling's slope. Refer to NFPA 72 for
details on requirements for sloped or peaked ceilings.

IMPORTANT! PLEASE READ CAREFULLY AND SAVE.

This user’s manual contains important information about your
Combination Carbon Monoxide & Smoke Alarm’s operation. If you are
installing this Alarm for use by others, you must leave this manual—or
a copy of it—with the end user.

LISTED TO

ULC S531 and

CSA 6.19

STANDARDS

IF YOUR CO ALARM SOUNDS

IF THE ALARM SIGNAL SOUNDS:

1. Immediately move to fresh air—outdoors or by an open door or

window. Do a head count to check that all persons are accounted
for. Do not re-enter the premises, or move away from the open
door or window until the emergency services responder has
arrived, the premises have been aired out, and your CO Alarm
remains in its normal condition.

2. Call your emergency services, fire department or 911. Write down

the number of your local emergency service here:

______________________________________________________

“ALARM-MOVE TO FRESH AIR”

If you hear the alarm horn and the Red light is flashing,

move everyone to a source of fresh air.

DO NOT disconnect the batteries from the CO Alarm!

Reviews: