Blinking Green Light On First Alert Smoke Detector: Is It Serious?

No, a blinking green light on a First Alert smoke detector means nothing serious. Blinking green light is part of its normal programming procedure which can happen in three circumstances-

  • During a power-up cycle
  • Adding a One Link alarm
  • If it’s battery is low

In the next sections, we will discuss more about the blinking green light on the First Alert smoke detector.

Key Takeaways

  • It is normal for a First Alert smoke detector to blink green. It can happen during a power cycle and adding another One Link alarm.
  • You may also need to replace the batteries if the battery is low.
  • No matter what light your smoke detector is blinking, you should always take proper care of it.

Blinking Green Light On First Alert Smoke Detector: Reasons

First Alert Smoke Detector
Source: Popular Mechanics

There are a couple of reasons why there is a green light flashing in your First Alert smoke detector. Let’s see what those are-

Reason One: Normal Power-Up Cycle 

The First Alert smoke detector keeps flashing green when it goes through a power-up cycle. No need to worry about this, it’s completely normal.

Power problems, brownouts, surges, or other power problems trigger the plug-in carbon monoxide alarm to power up. You’ll see the green light flashing for 5 minutes, then it’ll stay steady green. 

This power-up cycle occurs with all First Alert smoke detectors.

Reason Two: When You Add an Additional One Link Alarm 

You will see a green light on your First Alert smoke detector if you add another One Link alarm. Linking occurs in this way as well, and is normal. 

When linking the One Link alarm, press and hold the test button until the alarm chirps and flashes green. In this case, if the device doesn’t flash a green light it means the linking process has failed.

Normal Power-Up Cycle
Source: Home Stuff Mag

Reason Three: Low Battery Or Missing  Battery 

A First Alert smoke detector with a low or missing battery will flash green every two seconds. The battery should be replaced every hour and a chirp should be heard every minute.

Here’s how to change the battery on your First Alarm smoke detector: 

  • Gently pop open the cover of the smoke detector. It may have a latch or hinge mechanism to make it easier.
  • Remove the old battery by sliding it out carefully. Some batteries might be held in place with a clip or other securing mechanism. Be cautious not to damage the wires or connectors while removing the old battery.
  • Insert the new battery into the slot. Make sure to align it properly; it usually only fits in one direction. 
  • Push the new battery firmly into place until it’s secure.
  • The smoke detector’s cover should be closed. Put it in place properly by latching or securing it.

Test the smoke detector by pressing the “Test” button. It should sound a brief alarm to indicate that it’s functioning correctly. You should now see a steady green light, indicating a healthy battery.

Replacing the battery would bring back the smoke detector to normal. But if you want to temporarily silence the message, you can press the test button. 

Tips For Maintaining Your First Alert Smoke Detector 

Your First Alert smoke detector keeps you safe by letting you know about potential danger. But it also needs some care and maintenance to perform its duty. The following tips will help you maintain your smoke detector:

  • You should test your smoke detector at least once a week to ensure that it is working properly.
  • Once a month, clean the exterior of your smoke detector. Use a household vacuum’s soft brush attachment or a can of clean compressed air for gentle cleaning.
  • Avoid using water, cleaners, solvents, or air compressor machines, as they can damage the unit.
  • Replace smoke alarm batteries once a year with 9-volt or AA batteries.
  • Never test your First Alert smoke alarm with real smoke, flames, or exhaust. Doing so can damage the unit. Instead, use a UL-certified liquid smoke detector tester for safe testing.
Products Features
CRC Smoke Test Brand Liquid Smoke Detector Tester Premium quality
Hembisen Smoke Detector Tester Premium quality
  • For alarms with a 10-year sealed battery, replace the entire alarm if you hear the end-of-life signal (typically five chirps).
  • Consider replacing the entire alarm every 10 years to ensure continued reliability.

Frequently Asked Questions (FAQs):

Why Is My Smoke Detector Blinking Green And Red? 

To indicate its status, your smoke detector blinks green and red. Whether it is in normal operation, in low battery or end-of-life mode, or if it has a potential fault. In order to ensure that your smoke detector functions correctly and is safe, it is essential to understand these signals.

How Do I Know If My First Alert Smoke Detector Is Working? 

To test if your First Alert smoke detector is working, hold the Test/Silence button for 3-5 seconds until there are 3 beeps, pauses, and then 3 more beeps. This confirms the alarm is functioning correctly. 

What does 3 beeps on First Alert mean? 

Three beeps on a First Alert alarm indicate that it has detected smoke in your home. Designed to alert you to potential fire or smoke hazards, this sequence sounds at 85 decibels.


Blinking green light on the First Alert smoke detector doesn’t mean trouble, so you can rest assured. Your smoke detector’s batteries will need to be changed in the worst case scenario. Regardless, you should be serious about the signals your smoke detector gives you.