It sounds like there might be a few potential issues causing this problem with your Kidde FX-278 system. First, ensure that the batteries are correctly installed and fully charged. If the batteries are old or depleted, they may not provide enough power for the alarm to function properly.
Secondly, check the connections between the alarm unit and any control panels or monitoring devices. Loose or damaged connections can prevent the system from operating correctly.
Lastly, make sure that the alarm is not in a “silenced” or “test” mode, which could prevent it from sounding during a real emergency. Refer to the user manual for instructions on how to check and adjust these settings.
If you’ve checked all of these potential issues and are still experiencing problems, it may be necessary to contact Kidde customer support for further assistance or to schedule a service call with a certified technician.