Checking the System

• First, you must check the system's batteries each month. This will ensure that the batteries and the unit are in working order. Pick one day, such as the first day of the month, to check your smoke detector. Do this every month. To check the smoke detector, you must press the button on the front of it. Hold the button down until you hear the beep. If you don't hear the beep, then the system is not working properly. It could be the batteries or the system itself.
  
  

The Batteries

• Replace the batteries by twisting your smoke detector to the left and removing it from the wall or ceiling. Use your thumb to open the battery compartment by sliding it backward. Remove the batteries and insert new ones. Replace the cover and then twist the smoke detector to the right to get it to lock back into place on your wall or ceiling. The batteries need to be replaced once each year, or more often if you don't hear a beep when checking the smoke detector.
  
  

The Unit

• No smoke detector will last forever. It is a good idea to begin keeping an eye on it after seven years. It will definitely need to be prepared before the 10th year hits. It is a good idea to have a back-up unit in case your smoke detector quits early. If you checked the unit by pressing the button and it didn't beep, and then you replace the batteries and it still didn't beep, then it is time to replace the unit. You may just opt to replace the smoke detector every seven years to be sure that it will be in working order if you have a fire.