Mount Sentinel students were sent home early on Friday, due to smoke on the premises, but are expected to be back in class by Monday.
"We made the choice to send the kids home to ensure their safety," Superintendent Jeff Jones told the Star.
"At this point we're not sure the extent of the smoke damage, and we were concerned that we didn't know the source."
By mid-afternoon the Crescent Valley Fire Department had gotten to the bottom of it, assisted by the Beasely Fire Department. They discovered smoke in multiple rooms.
"After an in depth inspection of a large portion of the school, we discovered the source as a burnt electrical motor on a roof top air conditioning unit. Thankfully damage was limited to that unit," wrote deputy chief Ryan Durand in a press release on Friday afternoon.
Students were allowed to return for their belongings at approximately 2:30 p.m.
"Thank you to staff and students for calm, orderly evacuation," SD8 posted on Twitter, shortly after announcing that buses had transported the students home.
The school's website was temporarily unavailable because all power needed to be shut off, but the district sent out the news via Twitter and plans to update the school website to keep parents informed.