The Waverly Fire Department was called to the middle school Monday after an alarm sounded just after 1:00 p.m. The building was evacuated at that point. Fire crews determined a single heat pump, which is part of the HVAC system, malfunctioned and set off the alarm. The heat pump was disconnected and the fire department gave the go ahead to re-occupy the building. Students and staff were outside the building for approximately 20 minutes.