Smoke detectors are absolutely necessary to the safety of your home. Every now and then, however, a detector will improperly chirp or sound a persistent alarm. If this happens, follow these directions:
If your detector is powered by a battery, remove it and replace it. If this does not fix the problem, you should replace the entire unit.
If your unit is hardwired, flip off all of your circuit breakers until the alarm stops. You can then turn them all back on, except for the breaker that the detector is on. You can then replace this detector with a new one and restore power to this circuit.