First Alert 9120 Series User Manual Download Page 3

The basic installation of this Smoke Alarm is similar whether you want 
to install one Smoke Alarm, or interconnect more than one Smoke Alarm. 
If you are interconnecting more than one Smoke Alarm, you MUST read
“Special Requirements For Interconnected Smoke Alarms” below before
you begin installation.

ELECTRICAL SHOCK HAZARD. Turn off power to the area where you
will install this unit at the circuit breaker or fuse box before beginning
installation. Failure to turn off the power before installation may result
in serious electrical shock, injury or death.

1. Using wire nuts, connect the power connector to the household wiring.

Improper wiring of the power connector or the wiring leading to the
power connector will cause damage to the Alarm and may lead to a
non-functioning Alarm.

2. Remove the mounting bracket from the base, and attach it to the 

junction box.

3. Plug the power connector into the back of the Smoke Alarm.

4. Position the base of the Smoke Alarm over the mounting bracket and

turn. The Alarm will remain secure over a wide rotation range to allow for
perfect alignment. When wall mounting, this will allow fine-tuning on the
positioning to compensate for misaligned wall studs and to keep the
wording level. The Alarm can be positioned over the bracket every 120°.
Rotate the Alarm until aligned properly.

5. Check all connections.

ELECTRICAL SHOCK HAZARD. Do not restore power until all Smoke
Alarms are completely installed. Restoring power before installation is
complete may result in serious electrical shock, injury or death.
6. Make sure the Smoke Alarm is receiving AC power. Under normal

operation, the Green power indicator light will shine continuously.

7. If the Green power indicator light does not light, TURN OFF POWER TO

THE JUNCTION BOX and recheck all connections. If all connections
are correct and the Green power indicator still does not light when you
restore the power, the unit should be replaced immediately.

8. Single Station Alarms: Test each Smoke Alarm. Press and hold the

Test/Silence button until the unit alarms. 
Interconnected Alarms: Press and hold the Test/Silence button until
the unit alarms. All interconnected Alarms should sound. The other
Alarms sounding only tests the interconnect signal between Alarms. 
It does not test each Alarm’s operation. You must test each Alarm
individually to check if the Alarm is functioning properly.

If any unit in the series does not alarm, TURN OFF POWER and recheck
connections. If it does not alarm when you restore power, replace it 
immediately.

SPECIAL REQUIREMENTS FOR INTERCONNECTED SMOKE ALARMS

•  Failure to meet any of the above requirements could damage the

units and cause them to malfunction, removing your protection.

•  AC and AC/DC Smoke Alarms can be interconnected. Under AC

power, all units will alarm when one senses smoke. When power is
interrupted, only the AC/DC units in the series will continue to send
and receive signals. AC powered Smoke Alarms will not operate.

Interconnected units can provide earlier warning of fire than stand-alone units,
especially if a fire starts in a remote area of the dwelling. If any unit in the
series senses smoke, all units will alarm. To determine which Smoke Alarm
initiated an alarm, see table:

During an Alarm:

On Initiating Alarm(s)  Red LED(s) flashes (flash) rapidly

On All Other Alarms 

Red LED is Off

After an Alarm (Latching):

On Initiating Alarm(s)  Green LED(s) On for 2 seconds/Off for 2 seconds

On All Other Alarms 

Green LED(s) On, Red LED(s) is Off

Compatible Interconnected Units

Interconnect units within a single family residence only. Otherwise all house-
holds will experience unwanted alarms when you test any unit in the series.
Interconnected units will only work if they are wired to compatible units and
all requirements are met. This unit is designed to be compatible with: 
First Alert

®

Smoke Alarm Models SA4120, SA4121B, SA100B and BRK

Electronics

®

Smoke Alarm Models 9120, 9120B, SC6120B, SC9120B, 7010,

7010B, 100S, 4120, 4120B, 4120SB, RM3 (Relay Module); BRK Electronics

®

CO Alarm Models CO5120BN, CO5120PDBN; BRK Electronics

®

Heat Alarm

Models HD6135F and HD6135FB.

Interconnected units must meet ALL of the following requirements:

• A maximum of 18 compatible units may be interconnected 

(Maximum of 12 Smoke Alarms).

• The same fuse or circuit breaker must power all interconnected units.

• The total length of wire interconnecting the units should be less than

1000 feet (300 meters). This type of wire is commonly available at
Hardware and Electrical Supply stores.

• All wiring must conform to all local electrical codes and NFPA 70 (NEC).

Refer to NFPA 72, NFPA 101, and/or your local building code for further
connection requirements.

STAND-ALONE ALARM ONLY:

Connect the white wire on the power connector to the neutral wire
in the junction box.

Connect the black wire on the power connector to the hot wire in
the junction box.

Tuck the orange wire inside the junction box. It is used for 
interconnect only.

INTERCONNECTED UNITS ONLY:

Strip off about 1/2” (12 mm) of the plastic coating on the orange
wire on the power connector.

Connect the white wire on the power connector to the neutral wire 
in the junction box.

Connect the black wire on the power connector to the hot wire in 
the junction box.

Connect the orange wire on the power connector to the interconnect
wire in the junction box. Repeat for each unit you are interconnecting.
Never connect the hot or neutral wires in the junction box to the orange
interconnect wire. Never cross hot and neutral wires between Alarms.

STAND-ALONE ALARM ONLY:

If you are only installing one Smoke Alarm, restore power to the
junction box.

INTERCONNECTED UNITS ONLY:

If you are interconnecting multiple Smoke Alarms, repeat steps
1-5 for each Smoke Alarm in the series. When you are finished,
restore power to the junction box.

8

4
3

1

5

4

3

1

5

2

A

B

}

}

A. Unswitched 120VAC 

60 Hz source

B. To additional units; Maximum = 18 total

(Maximum 12 Smoke Alarms)

1. Smoke Alarm

2. Ceiling or Wall

3. Power Connector

4. Wire Nut

5. Junction Box

6. Neutral Wire (Wht) 

7. Interconnect Wire

(Orange)

8. Hot Wire (Blk) 

FOLLOW THESE INSTALLATION STEPS

9. For new construction, place supplied dust cover over Alarm to prevent

damage from dust and construction debris. When construction is com-
plete, remove cover.

Smoke will not be able to reach smoke sensor while cover is in place.
Cover must be removed!

3

Summary of Contents for 9120 Series

Page 1: ...er reliable means of escape from an upper floor in case stairs are blocked BEFORE YOU INSTALL THIS SMOKE ALARM IMPORTANT Read Recommended Locations for Smoke Alarms and Locations to Avoid for Smoke Alarms before beginning This unit monitors the air and when smoke reaches its sensing chamber it alarms It can give you more time to escape before fire spreads This unit can ONLY give an early warning o...

Page 2: ...stall special units which use devices like flashing strobe lights to alert hearing impaired residents Installation of this unit must conform to the electrical codes in your area Articles 210 760 of NFPA 70 NEC NFPA 72 NFPA 101 ICC SBC SBCCI UBC ICBO NBC BOCA OTFDC CABO and any other local or building codes that may apply Wiring and installation must be performed by a licensed electrician Failure t...

Page 3: ...tarts in a remote area of the dwelling If any unit in the series senses smoke all units will alarm To determine which Smoke Alarm initiated an alarm see table During an Alarm On Initiating Alarm s Red LED s flashes flash rapidly On All Other Alarms Red LED is Off After an Alarm Latching On Initiating Alarm s Green LED s On for 2 seconds Off for 2 seconds On All Other Alarms Green LED s On Red LED ...

Page 4: ...vicing an AC or AC DC Smoke Alarm First turn off the AC power at the circuit breaker or fuse box Next remove the battery from Smoke Alarms with battery back up Finally press and hold the test button for 5 10 seconds to discharge the branch circuit 1 Remove the Smoke Alarm from the mounting bracket If the unit is locked to the bracket see the section To Unlock the Mounting Bracket 2 Disconnect the ...

Page 5: ... alarm will reset auto matically If the unit alarms get everyone out of the house immediately ELECTRICAL SHOCK HAZARD Attempting to disconnect the power connector from the unit when the power is on may result in electrical shock serious injury or death When an interconnected system of AC powered units is in alarm the alarm indicator light on the unit s that initiated the alarm will blink rapidly I...

Page 6: ...s from the sources of combustion particles stove furnace water heater space heater if possible In areas where a 20 foot 6 meter 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 burn...

Page 7: ... not provide sufficient warning to all residents or meet local fire protection ordinances regulations LIMITATIONS OF SMOKE ALARMS Smoke Alarms have played a key role in reducing deaths resulting from home fires worldwide However like any warning device Smoke Alarms can only work if they are properly located installed and maintained and if smoke reaches the Alarms They are not foolproof Smoke alarm...

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