A malfunctioning HVAC system led brought firefighters to Pleasant Valley Middle School just 16 minutes before school the beginning of winter break Friday. Vancouver Fire Department responded to the smell of smoke in the gym.The Vancouver Fire Department discovered that a filter had been sucked into the HVAC system and was causing the burning smell.“We could smell the smoke, but we couldn’t see the smoke,” said Principal Travis Drake. “It was minor. It smelled like a bonfire. The fire alarms didn’t go off.”Drake said staff had been on the roof “trying to find where the smoke smell was coming from.”But they couldn’t find anything, so they called 911. There was no damage.“We just have to replace the filter,” Drake said.The gym is a separate building from the rest of the campus. There were no students in the gym.The incident did not disrupt the school day. Classrooms were not evacuated.It was an early release day, and students were eating lunches in their classrooms before boarding school buses at 12:30 p.m.The Pleasant Valley campus includes both a primary and middle school at 14320 N.E. 50th Ave. The schools are in Battle Ground Public Schools.