Operating on 120 or 240 V single-phase incoming power, Series HGM incorporates electronic ignition with pilot; 24 V control system; and on/off burner switch. It includes 1/2 in. schedule 80 vertical coil assembly, natural gas or LP gas-fired natural draft with aspirating-type burner, and draft diverter. Heater is fork truck accessible and provides inlet/outlet quick connects as well as 12 ft jumper hose with quick connect.