Smoke from a defective heating unit force Tilford Elementary students to go outside for a few minutes just as classes were about to begin on Tuesday morning.

Nobody was injured, and students and teachers returned to the building shortly after the alarm sounded.

Resource teacher Cara Patterson said the problem was with the heating unit on the roof above her classroom, just a few steps from the office.

“I heard a big, strange noise, and then the unit shut off,” she said. “And then, smoke — a lot of smoke.”

Patterson walked to the office to report the problem. The fire alarm protocol began and soon the Vinton Fire Department arrived. There was no fire, and smoke was confined to the east wing of the building. Firefighters set up several fans to help remove the smoke.

The west wing of the building, which includes classrooms for grades 2-4, as well as the music room and gym, was not affected.

School returned to its regular schedule after the morning excitement. A text message from VS schools identified a faulty fan belt as the specific cause of the smoke.