Abstract: A power gas burner includes a plenum having front and rear walls and a side wall. A blast tube is connected to the front wall communicating with the plenum. A blower has its discharge connected to the plenum. An air-gas mixing tube is disposed in the blast tube with its discharge adjacent the distal end thereof and its inlet extending into the plenum, the mixing tube defining a secondary air passage with the blast tube. The mixing tube has an air-admitting opening adjacent its inlet communicating with the plenum. A gas line extends into the inlet of the mixing tube. A spider supports the discharge of the mixing tube and has legs engaging the distal end of the blast tube. A flame spreader disc is spaced from the discharge of the mixing tube, the diameter of the disc being generally equal to the diameter of the mixing tube at its discharge.