Easy Fixes for Alarms and Security Lights

June 30, 2015

Alarms protect property and lives, but you'll aggravate your neighbours if they are not set up correctly. Most problems with alarms come down to issues of power supply or poor installation and are usually simple to fix.

Easy Fixes for Alarms and Security Lights

My smoke alarm goes off for no reason

Position them properly

Smoke alarms are sensitive devices. If you have positioned them carefully, they'll need only minimal attention to keep them working reliably.

  • Don't place smoke alarms in kitchens, bathrooms, garages or next to fireplaces. Fresh paint may sometimes trigger alarms.
  • A regular chirping sound indicates the battery needs replacing — get and install a new one immediately. Don't remove the old battery until you are ready to install the new one.
  • Some alarms can be triggered by dust in the air and may sound when you do your spring cleaning. Open the alarm casing and vacuum the inside.


An erratic smoke alarm is dangerous, as it may fail to warn of a real fire. Test the unit every month.

The security light is faulty

Find the correct angle 

Automatic security lights are usually triggered by infrared radiation (heat) from an intruder. They are also fitted with a light sensor that prevents the light operating during the day. Security lights need careful positioning and setting up if they are to work effectively. If the light is switching on and off for no apparent reason, ask yourself:

  • Is it being activated by people or cars moving past the house? If so, angle the unit downward more to restrict its field of vision.
  • Can the sensor "see" other heat sources, such as air vents or other security lights? If so, re-position the sensor accordingly.
  • Are there overhanging branches near the unit? They could trigger an alarm on a windy day, so trim them back.

8 ways to prevent false alarms

Modern burglar alarm systems contain sophisticated electronics to prevent false alarms, but there are still a few steps you can take to keep your alarm from tripping when it's not needed.

  1. Your alarm comes with a battery within the main control panel. With a life expectancy of around five years, the battery keeps the system working even if the power fails. A dead battery means false alarms. Turn off the main power supply, remove the cover from the control panel (you'll need to undo a couple of screws), and remove the battery; buy and install a replacement.
  2. Remove the covers of the passive infrared (PIR) detectors in the rooms of your home and clean out insects or webs before replacing them.
  3. Ensure that the covers of the control panel and of the PIR detectors are secure or you may trigger the system's "tamper" alarm.
  4. Position PIR detectors away from heat sources, such as dishwashers, tumble dryers or security lights.
  5. Close windows before setting the alarm; the movement of curtains, plants or decorations in the breeze may be enough to trigger the alarm.
  6. Check that the two parts of a door or window sensor are correctly aligned — it's easy to knock one out of position when cleaning or moving furniture.
  7. Some wireless alarm systems can be affected by remote controls and other wireless devices. If the alarm goes off every time you change channels, you may need to select a different transmission channel for your alarm through its control panel.
  8. Monitored alarm systems — those connected to the alarm company via the telephone — may sound if the telephone line fails. Check that the phone is working and that it is still connected to the alarm box.
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