Abstract: A heat recovery system, the system having a fuel burner assembly. The fuel burner assembly having a pilot burner, an ignition source such as, an ignition transformer, a turbo compressed air inlet duct, a primary housing accommodating a burner rod and nozzle assembly and a secondary housing made of a combustion chamber, having an upstream secondary air mixing assembly and an air diffuser assembly.The fuel burner assembly being operably connected down stream to a heat transfer and recovery system having one or more, preferably two, heat exchangers of the convective heat exchange type and an exhaust or stack for the exit of spent flue gases. The fuel burner assembly being operably connected upstream to a turbo charger/turbo compressor. The turbo charger/turbo compressor being provided with a start up mechanism, the start up mechanism comprising an air eductor assembly, external air supply feed line, an external fuel supply source, a liquid/gaseous fuel burner and a mixing chamber assembly.