A fire alarm Thursday afternoon at Conway’s JC Penney store at 201 Skyline Drive was caused by a defective HVAC unit, according to the Conway Fire Department. 

Firefighters responded to the alarm at about 3:50 p.m., finding that employees and customers had already evacuated. 

According to Randy Freeman of CFD, firefighters traced the smoke to a rubber belt on the HVAC unit that had overheated, causing smoke that triggered a smoke detector in the store’s ductwork. 

Employees and customers were allowed to return after about 20 minutes, Freeman said.