Heating With Biodiesel In A Home Oil Furnace or Boiler


Biodiesel may be reliably burned in a standard home oil burning furnace or boiler with a few minimal modifications accomplished with off the shelf parts.

Biodiesel is technically “fatty acid methyl esters”, which may be made by chemically processing vegetable oil.  Note that biodiesel is not vegetable oil that is merely filtered or simply mixed with something else

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When biodiesel is blended with conventional heating oil in proportions up to approximately 20% or “B20”, no modifications are required at all.

As the proportion of biodiesel exceeds 20%, a few changes may be required for best results.  High proportions of biodiesel may eventually degrade the pump seal and cause it to start leaking.  Suntec makes a pump specifically designed for biodiesel that should prevent this problem.

Atomization may be improved by changing to a nozzle with a slightly lower nominal flow rating while increasing the pump pressure to achieve the original flow rate.

A standard Beckett “nozzle line heater” may be installed to help with startup, especially if the fuel tends to be cold.  This heater is much smaller than the heater required for burning waste oil, but can provide enough heat to ensure reliable ignition.

The biodiesel flame tends to be less bright than the standard heating oil flame, so sometimes the safety primary does not register the flame as being lit and shuts the burner down after the set delay.  If this is the case, be sure the Cad cell is clean and gets a clear view of the flame.  You can paint the inside of the blast tube white or silver to increase the amount of light from the flame that reaches the cell.  You can also relocate the sensor so that it gets a better view of the flame.  Do not bypass this safety!