Cavius alarm signals: beeps, chirps and lights
Cavius, a Danish maker now part of Carrier, sells some of the smallest photoelectric smoke alarms on the market (40 mm across), plus a wireless family of 65 and 78 mm smoke, heat and flood alarms that link to each other by radio. Its red LED flashes every 48 seconds to show the alarm is working, and the low-battery beep keeps the same 48-second rhythm. In the wireless manual, three short beeps every 8 seconds is the answer to a test, not a battery signal. On a linked system, a flood alarm sounds short, spaced beeps, unlike the groups of long tones used for smoke and heat.
If it is sounding a full alarm: the maker’s emergency instruction
Smoke alarm
Cavius: treat every alarm as a real fire. Alert young children and older people, and leave the house by your escape route without stopping to collect valuables. If the air is full of smoke, stay close to the ground and cover your mouth, with a wet cloth if you can. Call the emergency services once you are outside.
From FAQ & troubleshooting and Optical smoke alarm device, model 2103: user guide (UK).
The Cavius alarm on these pages senses smoke only. For a carbon monoxide alarm, follow its own maker’s instruction.
Every Cavius signal we could source, side by side
7 signals. Tap what it means to jump to the drawing, Cavius’s steps and the source. If your alarm’s pattern is not exactly one of these, check the manual for your model: Cavius models do not all use the same signals.
| What you see | What you hear | What it means |
|---|---|---|
| Red light | Full alarm, loud and continuous | Real alarm: Alarm: this alarm has detected smoke. |
| No light named by the maker | Full alarm, loud and continuous | Real alarm: Another alarm in your linked system has gone off. |
| One red flash about every 48 seconds | Silent | Normal operation: Normal: the alarm is working. |
| No light named by the maker | One chirp about every 48 seconds | Low battery: Low battery: the battery is reaching the end of its life. |
| One red flash about every 8 seconds | One chirp about every 8 seconds | Normal operation: Test passed (wireless alarms): you held the test button for at least 10 seconds, and every linked alarm that received the test signal answers with a single beep and an LED flash every 8 seconds for 2 minutes. |
| No light named by the maker | Three chirps about every 8 seconds | Fault: Smoke sensor fault (wireless alarms): after a test, an alarm that gives three short beeps every 8 seconds instead of one has a problem with its smoke sensor. |
| No light named by the maker | Silent | Hush or silence mode: Hush: the alarm is paused for 10 minutes, then goes back to its normal alarm function by itself. |
Loud alarm in groups of three long tones, red LED flashing
Real alarm · smoke
Alarm: this alarm has detected smoke. On the Wireless Family it also radios the alarm to every linked alarm, which sound the same pattern after a short delay. Cavius uses this pattern, drawn in its manual as “--- --- ---”, for life-threatening alarms: smoke and heat.
- What you see
- Red light
- What you hear
- Full alarm, loud and continuous
Do this first: Cavius’s smoke alarm instruction, top of this page
What Cavius says to do about this signal
- Follow the fire instructions at the top of this page.
- If you are sure it is a false alarm from cooking or a fireplace, press the test button on this alarm (the one whose LED is flashing) to pause it for 10 minutes. Cavius’s FAQ names dust, humidity and small insects in the smoke chamber as causes of false alarms, solved by vacuuming the mesh and drying the alarm.
Source:
- Cavius: Optical smoke alarm device, model 2103: user guide (UK) — Wireless Family smoke alarm 2103, 5-year battery (document 127786 rev15). www.cavius.com Checked 2026-10-13.
- Cavius: FAQ & troubleshooting — Cavius smoke alarms in general (battery, smoke alarm and known-errors questions). www.cavius.com Checked 2026-10-13.
Alarm sounding but its LED is not flashing (wireless linked alarms)
Real alarm · smoke
Another alarm in your linked system has gone off. Cavius says only the originating alarm flashes its LED, so the one with the flashing LED is where the smoke, heat or water was detected. Short, spaced beeps (“- - -” in the manual) instead of groups of long tones mean a linked flood alarm, which Cavius calls non life-threatening.
- What you see
- No light named by the maker
- What you hear
- Full alarm, loud and continuous
Do this first: Cavius’s smoke alarm instruction, top of this page
What Cavius says to do about this signal
- Treat groups of long tones as a real fire and follow the instructions at the top of this page; the fire is probably in another room.
- To pause a false alarm, find the alarm whose LED is flashing and press its test button: Cavius makes you go to the source so that you check it is not a real fire first.
Source:
- Cavius: Optical smoke alarm device, model 2103: user guide (UK) — Wireless Family smoke alarm 2103, 5-year battery (document 127786 rev15). www.cavius.com Checked 2026-10-13.
Red LED flashes once every 48 seconds, no sound
Normal operation · smoke
Normal: the alarm is working. Cavius recommends checking every week that the LED still flashes at this rhythm.
- What you see
- One red flash about every 48 seconds
- What you hear
- Silent
If it is sounding a full alarm instead: Cavius’s emergency instruction, top of this page
What Cavius says to do about this signal
- Nothing to do. Cavius recommends a full test with the test button once a month, or at least once a quarter.
Source:
- Cavius: Optical smoke alarm device, model 2103: user guide (UK) — Wireless Family smoke alarm 2103, 5-year battery (document 127786 rev15). www.cavius.com Checked 2026-10-13.
- Cavius: FAQ & troubleshooting — Cavius smoke alarms in general (battery, smoke alarm and known-errors questions). www.cavius.com Checked 2026-10-13.
Short beep every 48 seconds
Low battery · smoke
Low battery: the battery is reaching the end of its life. On the wireless 2103 the beep goes on for 30 days, and only the alarm with the low battery beeps; the other linked alarms stay quiet, so the beeping one is the one to deal with.
- What you see
- No light named by the maker
- What you hear
- One chirp about every 48 seconds
If it is sounding a full alarm instead: Cavius’s emergency instruction, top of this page
What Cavius says to do about this signal
- On a 5-year model such as the 2001 or 2103, replace the battery the right way round, click the alarm back into its base, and test it. A wireless alarm keeps its link codes through a battery change.
- A Cavius 10-year alarm’s battery cannot be replaced: replace the whole alarm. The end-of-life date is printed on the label inside the battery compartment.
- If it still beeps with a good battery, Cavius’s FAQ says dust in the smoke chamber or dirty battery terminals can cause it: vacuum the mesh, and clean the terminals on the battery and the alarm, preferably with alcohol.
Source:
- Cavius: Optical smoke alarm device, model 2103: user guide (UK) — Wireless Family smoke alarm 2103, 5-year battery (document 127786 rev15). www.cavius.com Checked 2026-10-13.
- Cavius: FAQ & troubleshooting — Cavius smoke alarms in general (battery, smoke alarm and known-errors questions). www.cavius.com Checked 2026-10-13.
A beep and a red flash every 8 seconds for 2 minutes, after a test
Normal operation · smoke
Test passed (wireless alarms): you held the test button for at least 10 seconds, and every linked alarm that received the test signal answers with a single beep and an LED flash every 8 seconds for 2 minutes. That means it is connected and working.
- What you see
- One red flash about every 8 seconds
- What you hear
- One chirp about every 8 seconds
If it is sounding a full alarm instead: Cavius’s emergency instruction, top of this page
What Cavius says to do about this signal
- Nothing to do. A short press of the test button stops the signal early on each alarm.
- If an alarm does not join in, Cavius says radio noise during the test can stop it: try again later.
Source:
- Cavius: Optical smoke alarm device, model 2103: user guide (UK) — Wireless Family smoke alarm 2103, 5-year battery (document 127786 rev15). www.cavius.com Checked 2026-10-13.
- Cavius: FAQ & troubleshooting — Cavius smoke alarms in general (battery, smoke alarm and known-errors questions). www.cavius.com Checked 2026-10-13.
Three short beeps every 8 seconds, after a test
Fault · smoke
Smoke sensor fault (wireless alarms): after a test, an alarm that gives three short beeps every 8 seconds instead of one has a problem with its smoke sensor.
- What you see
- No light named by the maker
- What you hear
- Three chirps about every 8 seconds
If it is sounding a full alarm instead: Cavius’s emergency instruction, top of this page
What Cavius says to do about this signal
- Vacuum around the smoke chamber with the vacuum cleaner on a low setting, then test again.
- A short press of the test button stops the indication early. If the fault comes back, Cavius points to the troubleshooting pages on cavius.com.
Source:
- Cavius: Optical smoke alarm device, model 2103: user guide (UK) — Wireless Family smoke alarm 2103, 5-year battery (document 127786 rev15). www.cavius.com Checked 2026-10-13.
Silent for 10 minutes after you pressed the button during an alarm
Hush or silence mode · smoke
Hush: the alarm is paused for 10 minutes, then goes back to its normal alarm function by itself. On the wireless alarms only the alarm that started it (the one with the flashing LED) can be paused. On the 40 mm 2001 you press the side button.
- What you see
- No light named by the maker
- What you hear
- Silent
If it is sounding a full alarm instead: Cavius’s emergency instruction, top of this page
What Cavius says to do about this signal
- Use it only for a false alarm you have checked, such as cooking or a fireplace. If smoke is still there after 10 minutes, it will sound again.
Source:
- Cavius: Optical smoke alarm device, model 2103: user guide (UK) — Wireless Family smoke alarm 2103, 5-year battery (document 127786 rev15). www.cavius.com Checked 2026-10-13.
- Cavius: Model 2001 manual (DE/UK) — Smoke alarm 2001, 40 mm, 5-year battery (document 127773 rev10). www.cavius.com Checked 2026-10-13.
- Cavius: FAQ & troubleshooting — Cavius smoke alarms in general (battery, smoke alarm and known-errors questions). www.cavius.com Checked 2026-10-13.
Sources
Every line on this page comes from Cavius’s own documents, read on the date shown. Nothing is taken from third-party code sites or other makes.
- Cavius: Optical smoke alarm device, model 2103: user guide (UK) — Wireless Family smoke alarm 2103, 5-year battery (document 127786 rev15). www.cavius.com Checked 2026-10-13.
- Cavius: Model 2001 manual (DE/UK) — Smoke alarm 2001, 40 mm, 5-year battery (document 127773 rev10). www.cavius.com Checked 2026-10-13.
- Cavius: FAQ & troubleshooting — Cavius smoke alarms in general (battery, smoke alarm and known-errors questions). www.cavius.com Checked 2026-10-13.