Light smoke from air conditioning units at a preschool in Valencia on Monday afternoon led to an L.A. County Fire Department response and a brief evacuation, according to officials and reports from the scene.  L.A. County Fire Department personnel were dispatched to 23720 Wiley Canyon Road at 1:33 p.m. on Monday and were on scene at 1:37 p.m., according to Bernard Peters, spokesman for the Fire Department.  L.A. County firefighters deal with a smoking HVAC unit at Cadence Academy Preschool in Valencia on Monday afternoon. 101424 Maya Morales/The Signal Peters said there was smoke visible inside the building that was likely due to the HVAC system, but personnel were checking for the source.  Most of the units had been cleared by 1:55 p.m., according to Peters.  A report from the scene indicated that Cadence Academy Preschool was evacuated, and a teacher at the school was with Fire Department personnel inside the building.   L.A. County firefighters clear classrooms at Cadence Academy Preschool after a brief evacuation for a smoking HVAC unit on Monday afternoon. 101424 Maya Morales/The Signal Students and staff were being let back in the building just after 2 p.m.  According to Battalion Chief Eric Suarez, the smoke was coming from an old HVAC system that was turned off prior to the evacuation being lifted. The post Valencia preschool briefly evacuated after smoke seen inside building  appeared first on Santa Clarita Valley Signal.