Waste Oil Heater Forum - Your definitive source for burning waste oil for heat.

Hello im new to waste oil heaters. My plan is to start my furnace on fuel oil then after the fire box gets some heat build up switch it over to waste oil. I plan on teeing in to the pump inlet with two valves one  with fuel oil the other with waste oil.As it starts on fuel oil i plan on slowly turning off the fuel and turning on the waste oil. Also im looking for ways to preheat the oil. Im not sure im too comfortable with putting a heating element into the oil..What if the element shorts out? Is there a risk of fire. im thinking maybe taking a small water heater and wrapping my oil tank with hot water filled copper tubing,and heavy insulation. Also running it the length of pipe to the inlet valve. Like i said im new so i am very open to any and all comments or suggestions. Thank You in advance for your time and comments.