Maintaining Smoke Detectors

Smoke detectors are important safety devices that require periodic maintenance.

First, carefully remove the smoke detector's cover.

Remove the sensor to access the battery and other components.

You can test the battery in place or remove the smoke detector to remove the battery.

Smoke detectors and smoke alarms are complex, specialized devices that are also relatively inexpensive, so when one starts acting up, the first thing to consider is throwing it out and buying a new one. However, there are many things you can do to save yourself some money, time, and trash. You can fix it!

A smoke detector is a small device that sounds an alarm when it senses smoke or fire. There are two kinds of smoke detectors—photoelectric and ionization. Photoelectric units throw out a beam of light that, if broken by smoke will trigger an audible alarm. Ionization units give nearby air an electrical charge and measure whether the charge stays constant; if not there probably is a fire present eating up the oxygen in the air, so the alarm goes off. Photoelectric detectors are better where smoldering fires might be, such as electrical fires in walls, making them a good choice for bedrooms and kitchens. Ionization units are better in areas where a controlled fire might get out of control such as in a furnace room. Some models combine both types of detectors. Smoke detectors are either powered by an internal battery or household current backed up by an internal battery. Some smoke detectors are part of a home Security System.

To test a smoke detector:

Press the battery-test button on the unit to make sure the battery is properly connected.
If the unit has a battery that's more than a year old, replace the battery (see below).
Light a candle and hold it approximately 6 inches below the detector so that heated air will rise into the unit.
If the alarm doesn't sound within 20 seconds, blow out the candle and let the smoke rise into the unit.
If the alarm still doesn't sound, open the unit up and make sure it is clean and that all electrical connections are solid.
If, again, the alarm doesn't sound, replace the smoke detector.

To replace a smoke detector battery:

Remove the smoke detector cover, typically by carefully pulling down on the case's perimeter or by twisting the case counterclockwise.
Locate and remove the battery. Use a multimeter (see Testing With a Multimeter) to test battery voltage. As needed, replace it with a new one.
Close the case and test the smoke detector (see above).
Read the owner's manual for additional troubleshooting tips and possible adjustments.