Martimemedic you may have a good point there.. There are a couple different products that often get sold as Propane.. one is, of course Propane.
But especially in the south. Many times BUTANE gets substituted.. now, if you are filling the BBQ tank, you really do not notice the difference, since you almost never use a BBQ below freezing, and the major difference is that Butane burns a bit hotter (not much, just a tiny bit) so you may actually use less gas..
Of course Butane is way way cheeper than propane so by sellling Butane at propane prices the dealer is making a big profit.
But,,,, For RVers who often DO run the furnace when it's sub zero (C) (that is below freezing) it makes a BIG difference,,, Cause Butane won't vaporize when it is that cold.
And of course it is false advertising, so it's criminal.
But.. The point is this: I'd bet the air/fuel ratio is slightly different for Butane as well. So adjusting the furnace,, on one fuel, then getting a load of the other, can cause a "Bad mix" yellow flame.
