D249 series boiler bases are pre-assembled at the factory with burner manifold, burner orifices, gas valves and electronic ignition installed, ready for field installation of the pre-tested sections and appropriate packages Mid-efficiency Atmospheric combustion, vertical vent Plug n play harness and junction box individual base and junction box controls are designed for easy installation with plug n play harnesses The entire boiler links together in a "snap" A color-coded factory supplied harness eliminates wiring errors Harness wiring mounts externally for easier field installation Control panel mounts externally on the front of the boiler under a protective hood The control panel sees a lower operating temperature, installation time is reduced and the unit is easier to service