Smoke from a faulty furnace fan caused the evacuation of St. Paul's Lutheran Preschool late Friday morning.
Seven students, director Crystal Newby and two parents were in the building when the smoke detectors started going off.
The students were quickly put in coats and led outside a safe distance from the building.
When fire units arrived they searched the building and discovered the fan on the furnace was not working, said Pratt Fire Chief David Kramer.
Firefighters watched the furnace and saw the burners go through several cycles and then shut off. But the fan never came on to push the heat through the ductwork and that was the problem, Kramer said.
When the furnace got too hot it began putting off an odor and smoke that set off the smoke detectors. Limit switches, that prevent the furnace from getting too hot, kicked in and shut the furnace down.
Newby said the first indication she had that something was wrong was the smoke detectors going off. She and the two parents quickly got the children out of the building and called 911.
The incident happened right at the end of the morning session and parents had already arrived to pickup children so the students didn't have to spend much time outside in the cold, Newby said.
The building suffered only very light smoke damage and no one was injured in the incident.