BRK electronic 4120 AC User Manual page 10

To Lock The Battery Compartment
(Models 4120B and 4120SB Only)
Do not lock the battery compartment until you have
activated the battery and tested the battery back-up.
1. Activate the battery
back-up by removing
the "Pull to Activate
Battery Back-Up" tab.
2. Push and hold test
button until the alarm
sounds: 3 beeps, pause,
3 beeps, pause.
If the unit does not alarm during testing, DO NOT
lock the battery compartment! Install a new
battery and test again. If the Smoke Alarm still
does not alarm, replace it immediately.
3. Using needle-nose pliers
or a utility knife, detach
one locking pin from the
mounting bracket.
4. Push the locking pin
through the black dot on
the label on the back of
the Smoke Alarm.
To Unlock The Battery Compartment
(Models 4120B and 4120SB Only)
Once the Smoke Alarm is installed, you must
disconnect it from the AC power before unlocking
the battery compartment.
ELECTRICAL SHOCK HAZARD. Turn off the power
to the area where the Smoke Alarm is installed
before removing it from the mounting bracket.
Failure to turn off the power first may result in
serious electrical shock, injury or death.
Always discharge the branch circuit before servicing
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 power connector by gently prying
it away from the back of the Smoke Alarm.
3. Insert a flathead screw-
driver under the head of
the locking pin, and gen-
tly pry it out of the bat-
tery compartment lock.
(If you plan to relock the
battery compartment,
save the locking pin.)
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