Real alarm · First Alert · smoke
First Alert: Three beeps, pause, repeating, red LED flashing, escape light on
Smoke is detected. During an alarm the SM210L sounds 3 beeps, pause, 3 beeps; the red LED flashes rapidly and the escape light is on. (Pressing the test button gives the same pattern once.)
- What you see
- Three red flashes
- What you hear
- Full alarm, three beeps then a pause, repeating
Do this first: the maker’s emergency instruction
Smoke alarm
First Alert (SM210L manual): if the alarm sounds, get everyone out of the house immediately — do not stop to dress or collect anything. Feel doors with the back of your hand and do not open a hot one; cover your nose and mouth with a damp cloth; meet at your planned place outside and count heads; call the fire department from outside, giving your address and then your name; never go back inside a burning building.
From User’s Manual — Smoke Alarm, 10-Year Sealed Battery with Escape Light.
The First Alert alarm on these pages senses smoke only. For a carbon monoxide alarm, follow its own maker’s instruction.
What First Alert says to do about this signal
- If you are not testing it, First Alert says the alarm is warning you of a potentially dangerous situation and must never be ignored.
- For an unwanted alarm (cooking smoke), First Alert says to open a window or fan the smoke away; the alarm resets by itself.
From User’s Manual — Smoke Alarm, 10-Year Sealed Battery with Escape Light and Why Is My Smoke Detector Beeping (Safety Corner). If your alarm’s pattern is not exactly this, check the manual for your model: First Alert models do not all use the same signals.
Other First Alert signals
Real alarm on other brands
The same state sounds and looks different on each make — which is why a chirp pattern cannot be read without the brand.
Sources
Every line on this page comes from First Alert’s own documents, read on the date shown. Nothing is taken from third-party code sites or other makes.
- First Alert (BRK Brands): User’s Manual — Smoke Alarm, 10-Year Sealed Battery with Escape Light — Model SM210L. support.firstalert.com Checked 2026-09-29.
- First Alert: Why Is My Smoke Detector Beeping (Safety Corner) — First Alert smoke alarms (general article). www.firstalert.com Checked 2026-09-29.