At 12:00 noon Station 20 was dispatched by Westmoreland 911 for a reported automatic fire alarm on Douglas Dr. Also dispatched was Sardis , White Valley , Export and Medic One to assist. Lieut 20 arrived on scene with nothing showing from the front of the residence. After talking to the homeowner he found that a bad battery in the system set off the alarm. Lieut 20 advised 911 to cancel all units as truck 20 and engine 22 were approaching. All units went back in service