In ,
gonjah typed:
On 10/24/2014 5:19 PM, wrote:
Air for the stove is brought in through a 3" pipe from outside the
house. The top of the chimney is about a foot above the highest part
of the roof. . . . ,
Out of curiosity: How high does the chimney extent above the roof
where it comes out of the roof? My thought is the chimney *might* not
be exposed to enough cold air. We used to get smoke in the house when
it wasn't cold enough outside to get the chimney cold enough to
create a good draft. Apologies if you've already addressed this. I
haven't read all of the responses. I guess another question could be:
How cold is it outside when you fire up your fireplace? Is it
blustery cold or just cool outside? I could only use my wood burning
stove when it was really cold. Otherwise it would smoke up the place,
but my chimney was only about 4 feet above the roof line. On *really*
cold nights it worked fine. But it wouldn't get really cold until
late November. I wouldn't think of using it in October.
I am fairly certain that the code regarding the height of the chimney is
determined, in part, by the type of roof (sloped or flat) and how far the
top of the chimney is "HORIZONTALLY" from the nearest point on the roof or a
wall or other obstruction.
Basically, I think that if the top of the chimney is above the top of the
roof line, it is supposed to be at least 2 feet above the top of the roof
line. This also assumes that there is no wall or side of a building within
about 10 feet of the chimney.
For a sloped roof, where the top of the chimney is not above the top of the
roof line, the HORIZONTAL distance from the top of the chimney to the roof
is supposed to be at least 10 feet (again assuming that there is no
additional wall or side of a building near the chimney).
There are exceptions for chimneys where the only fuel being used from the
furnace and/or hot water heater below is natural gas and the chimney itself
that is coming through the roof made of what they call "B-vent".
One concept is to prevent a "down draft" down into the chimney caused by
wind across the roof.
And, I think that another concept is to have the chimney be such that it is
somewhat insulated from the outside cold air (which is one role of B-vent)
so the gases remain hot enough to continue to rise up and out of the chimney
and without causing water condensation inside the chimney.