Ei Electronics alarm signals: beeps, chirps and lights
Ei Electronics (Ireland; Aico is its UK arm) uses a 48-second beat on its current 3000 and 600 series: one, two or three chirps with the same number of yellow flashes are low back-up battery, sensor fault and end of life. Its CO alarms flash red faster as the gas level climbs, before the alarm sounds.
If it is sounding a full alarm: the maker’s emergency instruction
Smoke alarm
Ei Electronics: a continuous alarm from a smoke or heat alarm may mean fire — if in doubt, always assume it is real. Check doors for heat and use another route if one is hot; crawl low under heavy smoke; get out as fast as you can without stopping to pack; meet at your prearranged place; call the Fire Brigade immediately on a mobile or from a neighbour’s house, for every fire however small; never re-enter a burning house.
From Products FAQs — Why is my fire alarm beeping? / Why is my alarm beeping? and Ei3028 / 3018 Alarms Instruction Manual.
Carbon monoxide alarm
Ei Electronics: open doors and windows if it is safe to, turn off all fuel appliances where possible, and leave the property with the doors and windows open. Get medical help at once for anyone with symptoms (headache, nausea) and say CO poisoning is suspected. Ring your gas or fuel supplier’s emergency number. Do not go back in until the alarm has stopped, and do not use the fuel appliances again until an expert has checked them (for gas, a Registered Gas Installer).
Every Ei Electronics signal we could source
| What you see | What you hear | What it means |
|---|---|---|
| One red flash about every half a second | Full alarm, loud and continuous | Real alarm: There may be a fire. |
| Red light | Full alarm, three beeps then a pause, repeating | Real alarm: There may be dangerous levels of CO. |
| Two red flashes about every 4 seconds | Silent | Early warning: CO is being detected and the alarm will sound if it stays: two flashes every 4 seconds at 50 ppm (alarm within 60–90 minutes), three at 100 ppm (within 10–40 minutes), four at 300 ppm (within 3 minutes). |
| One yellow or amber flash about every 48 seconds | One chirp about every 48 seconds | Low battery: The back-up battery is low (3000 and 600 series). |
| Two yellow or amber flashes about every 48 seconds | Two chirps about every 48 seconds | Fault: There could be a fault with the sensor. |
| Three yellow or amber flashes about every 48 seconds | Three chirps about every 48 seconds | End of life: The alarm has reached the end of its life. |
| Four yellow or amber flashes about every 8 seconds | Four chirps about every 8 seconds | Fault: The alarm’s built-in dust compensation has reached its maximum: the optical chamber is contaminated by dust or insects. |
| One red flash about every 40 seconds | One chirp about every 40 seconds | Low battery: Low battery on a 140e series alarm, which has a replaceable battery. |
| No light named by the maker | One chirp, no fixed interval | Fault: The alarm is not getting mains power (the green light shows mains power). |
Sources
Ei Electronics’s own documents only, read on the date shown.
- Ei Electronics: Products FAQs — Why is my fire alarm beeping? / Why is my alarm beeping? — Ei 3000 series, 600 series, 140e series and CO alarms (FAQ). www.eielectronics.ie Checked 2026-09-29.
- Ei Electronics: Ei3028 / 3018 Alarms Instruction Manual — Ei3028 multi-sensor heat and CO alarm, Ei3018 CO alarm (document B20223 R5, Irish edition). www.eielectronics.ie Checked 2026-09-29.
- Ei Electronics: Basic Alarm Fault Finding — Ei alarms (fault-finding page). www.eielectronics.ie Checked 2026-09-29.