Principal Constance McAllister told Action News she noticed the problem when she first arrived at the school Thursday morning.
The front part of the building in the 200 block of West 9th Street was warm, McAllister said.
But the temperature dropped as she walked farther into the facility, and some parts of the building had no heat at all.
Students were assembled in the cafeteria for an early lunch starting at 10:00 a.m. and then sent home for the day.
Teachers were asked to stay, McAllister said, because some parts of the building do have heat.
The teachers were meeting in heated parts of the building to participate in developmental workshops.
Stay with Action News and 6abc.com for more information on this story as it becomes available.