Thread: Dual-Fuel heating - Fuel Oil & Wood

Yep, I've finally seen it - the "good old boy" version of a dual-fuel heating system. A Lennox oil fired furnace (circa 1980), with ducting connected to a wood (yep, wood) furnace. Two thermostats, so when the wood furnace dies down, he has somehow rigged a vent flap in the plenum of the wood furnace to swich to the oil fired furnace duct system. Couldn't get a good photo of the entire system because they're all sandwiched into a tight basement further crowded by the oil storage tanks, well pressure tank, and laundry room. And I did not dismantle the plenum to see how that part was rigged (would have been interesting, but didn't have the time).

Now my real questions. Does anyone have the flue temperatures of wood furnace exhaust as compared to an oil fired furnace? (Yep, they share the same chimney too!, I'm sure he was trying to save space). I know its not allowed, but was curious about the possible effects of combining the two exhaust vents (must make great creosote).

I see all kinds of strange heating systems in the last great frontier (mostly gas or LP, a lot of wood stoves and fireplaces), but I see very few oil fired furnaces. I know they're very common in the Northeast. Does anyone have a good cheatsheet of common issues to check on an oil furnace inspection? For example, are vents required for an indoor fuel storage tank, any special rules when there are two tanks connected together (fill valve, shut off valves, etc)? Draft requirements?

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Found a picture

Terry. Attached is MA code on Oil Burning Equipment. The tanks must be vented to the exterior. Two tanks connected together are addressed under 4.03 K. Hope it helps.