Low budget wood stove conversions are always difficult to stabilize. Yet so many seem to want to do this type of conversion. I have suggested that while a wood stove can be converted…it is almost impossible to safely convert it to use both wvo and wood at the same time. WVO can fairly simply be made to drip into a “log replacer” since it can produce a stable fire. Wood cannot. Oh it can be banked to last…but it cannot be made to produce a steady long term stable production of heat. Eventually the batch of wood changes its fuel characteristics and so changes its output of heat. I have created wick type “log replacements” for wood stoves. They are fairly simple to make in 30 minutes with a welder.
The oil “drip feed” is a bit trickier. First the viscosity of the wvo must be stabilized and made independent of the ambient temperature. This can be easily accomplished by insulating the wvo tank and placing an inexpensive low watt thermostatically controlled electric heater in it. Next the wvo must not be allowed to cool while on its’ way to the burner. This is easily accomplished with standard self regulating heat tape. The flow regulating valve is best placed on the wvo tank outlet but must in any case be located away from any heat generated by the stove. Since it is at this critical point that it is most important to have a stable and regulated temperature. I suggest insulating the valve and wrapping it with the same heat tape used on the rest of the insulated wvo line. It is not as cheap but it is simpler to use the self regulating heat tape to heat not only the wvo delivery line but the wvo tank as well…and if well insulated a second independent heat tape circuit may be used around the outside of the insulated tank..inside the insulation..to provide this function.
OK..so now we have a stable flow from the tank…to the valve..and into the “log replacer” wick heater unit. Essentially this is just a big multiwick wvo fueled candle. As the wvo flows into the pan it is soaked up by the wicks which vaporize and ignite it. How clean this burns is regulated by wick trimming. Since the output is stable the wvo can be regulated to not flow into the pan faster than it is burned with a bit of care. Air must be allowed into the firebox in an “overair” amount and any damper must be provided with a positive stop…since if the draft becomes the limiting factor in combustion the wvo may accumulate and over flow causing a major fire hazard..or worse. Too much draft may also cause the flames to blow out (though it takes a lot) and the wvo to cease to be consumed..resulting in a mess.
One simple safety mechanism is to build the sides of the pan higher than the wicks…so they “drown” in wvo and are extinguished before the overflow condition is reached. An over flow outlet can be welded in to the pan below its top edge which allows the wvo to exit the pan into a overflow tank prior to spilling out of the pan as another option. I recommend both. This conversion can be used to replace the wood usually used in such stoves…but the resulting wvo stove is no more safe than the original it is derived from…and possibly a bit less safe. As an ex firefighter I can never stress enough the importance of fire safety. Personal awareness of what to do in case of a house fire has saved more lives than firemen ever will.
Make sure your smoke alarms work. Practice with your family how to GET OUT FAST in case of a fire till even your youngest wont freak out and hide. A fireman’s nightmare is trying to find a small child who has hidden themselves in a burning home! Nothing compared to the nightmare a parent goes through though waiting for both to emerge alive. And for your families sake..don’t fight the fire yourself. I was a trained professional..and took on a fire in my own home without protective gear. It saved my home by slowing the fires’ progress till the engines arrived…but I was pretty badly burned. Months of recovery…and I am not as pretty as I once was.