How to Troubleshoot a USI 1204 Smoke Detector

Check the breaker if the red LED light on the smoke detector is flashing every 40 to 45 seconds, but the green LED light is off. Switch the breaker back on if it has tripped or change the fuse if it is blown. Contact an electrical service professional if the power is fine, but the green LED light on the smoke detector remains off.

Check the house or building for smoke if the horn on the smoke detector beeps three times, pauses, then beeps three more times, and the red LED light is flashing repeatedly. Clear the home or business of all occupants and call the fire department unless the horn stops blowing after 10 seconds, indicating a test button has been pressed.

Turn off the power to the smoke detector if you hear a chirping sound every 40 seconds. Unscrew the cover and remove the battery. Replace it with a new 9-volt battery and remove the battery pull tab. Replace the cover and turn the power back on to the smoke detector. Press the test button down to verify the smoke detector is working properly.

Check all smoke detectors to verify power is functioning if one of the detector's horns does not sound during a test. Turn off the power, then unscrew the smoke detector from the mounting bracket. Verify the connector plug is tightly fastened to the unit.