chimney height

when figuring the"height" does that mean only the vertical height of chimney , or does it include the total length of chimney? From back of boiler outlet , horizontal runs and vertical height?

Reason i ask, my vertical height from metalbestos clean out T is 6' Overall. Total length of flue from back of boiler is 12'. would the actual vertical height need to be a minimum of 16' above cleanout T?

Is the cap of the metalbestos higher than the highest peak of the house...
If so you should be good...
My metalbestos run is short also but ends 4' higher than the peak...
Drafts very well...

wilder11354 wrote:when figuring the"height" does that mean only the vertical height of chimney , or does it include the total length of chimney? From back of boiler outlet , horizontal runs and vertical height?

It is rather informal. Some people measure from the ground to the top of the chimney but really should be the height from the appliance's breach to the top of the chimney. The horizontal stuff doesn't count, only the vertical distance.

not higher than peak of house, have a 10' Deep X 14'Wide deck, coal boilers in, with roof over it. Chimney comes out end wall about 9' from the house main wall, and top of coal boiler chimney is 5 feet above deck roof. deck roof is a 12/2 pitch. coal chimney is 9 feet from main house structure. Guess a picture would work best. Tomorrow for that.

coaledsweat wrote:

wilder11354 wrote:when figuring the"height" does that mean only the vertical height of chimney , or does it include the total length of chimney? From back of boiler outlet , horizontal runs and vertical height?

It is rather informal. Some people measure from the ground to the top of the chimney but really should be the height from the appliance's breach to the top of the chimney. The horizontal stuff doesn't count, only the vertical distance.

So i should add another 4 foot section of chimney. probably would help improve draft some.

2' above anything within 10' IIRC.

coaledsweat wrote:2' above anything within 10' IIRC.

That's right but I would add that the above requirement is an absolute minimum requirement to achieve at least a mediocre level of performance. I don't like to think of it as a recommendation, a recommendation would be go as high as you can (within reason) while exceeding both the rule and the highest portion of the home or structure that the stack will be located in by at least two feet. Most problems with draft are due to the stack effect of the home out-competing the draw of the chimney - especially for chimneys connected to basement appliances.

Do you have a manometer connected to see what your draft reading is? That would tell you if the additional chimney height is doing you any good or not (or even necessary).

wilder11354 wrote: So i should add another 4 foot section of chimney. probably would help improve draft some.

If the current chimney is below the roofline of the main house, then yes.