Has anyone modified a GAS furnace to burn wvo? I’m not talking about converting from gas to wvo, but adding a wvo burner. My gas furnace is 25 years old, is NOT high efficiency and has a metal flue leading to a metal lined chimney. Is it possible to do something like this: 1. Run steel tube (or copper?), perhaps 1/8” ID over the pilot of the gas burner, or possibly just over the gas burner. This would be the pre-heater for the wvo. 2. Use a peristaltic pump to draw wvo from a pail (pre-filtered?) through a flow valve. 3. Build some electronics to sense when the FAG burner turns on, possibly using a temperature sensor to ensure the wvo burner only comes on when the gas burner is on. 4. 30 seconds after the gas burner comes on, turn on the pump and start spraying hot wvo into the gas flames. Turn the pump off when the gas burner turns off.

My goal is to assist the gas by maybe 20%-50%. I might have to restrict the gas supply a bit so that the overall heat produced by the burner (gas+wvo) does not increase. The beauty of this system is that the thermostat, forced air system, ducting etc. is reused, and the system can be returned to FAG only very easily if/when we sell the house. Questions: Has anyone done this before? Am I crazy? Is a gas furnace appropriate for burning a small amount of wvo? I don’t want to burn my house down. What is the flame temperature of wvo vs. gas? What kind of chimney/flue is required? Will wvo leave a residue in my chimney? Any other negatives?

I guess you could build and modify anything if you have enough time and money. I don’t know your skills so when you say build some electronics, that could be a lot more difficult than you think. If you asking my advice, I’d say get a used oil furnace with a burner and experiment with wvo and leave the gas burner alone. Since we don’t get into gas burners at all here, just gun-style residential oil burners, I don’t know if gas burner combustion chamber is different that an oil burners.

If its a rack type gas unit I would not try it unless you want to melt it . If it has a gun type gas burner check your heater/furnace info from the manufacture and see if its a strait change or was there a additional fire box liner to go with it for oil. Some were made to be either gas-gun type or oil burner setup. Some older oil furnaces were changed at one point due to good sales people from the local gas supplier “GAS BURNS CLEANER and safer adds” buy simply removing the burner setup and putting in the gas gun setup.

If it was designed for gas only and not a combo choice unit, the fire chamber will not handle an oil burner. Gas units never have a flame that gets near any outside walls of the heating area so the metal is thin and will not handle a flame even licking it a bit.

Sounds scary and unsafe. Minor problems with flow and timing could cause big problems if it works at all. A “puff back” is a high risk. A peristaltic pump won’t supply enough pressure to get good atomization of the fuel. You also will need to change the amount of combustion air (or reduce the gas) as you add the WVO to keep the proper fuel air mixture ratio. The flame temperature is higher and might damage the heat exchanger in your furnace. A gas chimney is not rated for oil combustion. You will probably get a lot of residue in the furnace and chimney.