Power Flame's Fixed Air Direct Heating Gas Burner The Power Flame Type FD Burner is specifically designed to fire process air heating appliances that require heat application directly to the system air stream. This new generation burner is especially well suited for applications that move large quantities of air at high velocity. Factory fire tested and shipped as a complete assembly, all FD burners can be ordered with optional gas train and combustion control system or as a basic burner assembly only. The high tech combustion head design allows for turndowns in excess of 30 to 1 and short flame lengths while maintaining excellent flame stability across the entire modulating range. The FD fixed air damper simplifies operating system adjustment to provide trouble-free start up and reliable performance. Welded steel construction insures dependable operation and long service life. And low maintenance requirements means consistent, high efficiency operation and reliable performance between scheduled servicing