Heater Element for Coleman Electric Furnace S1-3500-412P/A. Electric Furnace Part Coleman part number S1-3500-412P. Heater Element with Limits 11.2 Kw. 240V. Replaces part number 3500-4121. Used in many Coleman EB12 Series and EB23 Series electric furnaces To see if this part is right for you contact your General Supply sales for more information.