Gainesville firefighters responded to the Jackson Building around 1:30 p.m. Thursday to what amounted to be a malfunction with the heating and air conditioning unit.

They discovered smoke on the third floor of the  building at 114 Washington St. and later discovered the malfunction, Gainesville Fire Chief Jon Canada said.

The building was evacuated and the traffic on Washington Street stopped for about an hour as firefighters responded.

They ventilated the smoke from the building using special fans, Canada said. Maintenance personnel along with HVAC contractors addressed the breakdown, he added.

It’s the second call in as many months having to do with downtown buildings and malfunctioning HVAC units.

“Calls like this are not unusual especially in older buildings or even residential homes,” Canada said.