Sometimes you need to call a professional… and sometimes you don’t.
Here are a number of tips to help resolve common problems with chimneys.
Constant smoking problems
Constant smoking problems are often the easiest to diagnose while being the hardest
to correct. Many constant smoking problems are the result of improper construction
or design and may require extensive modification of the chimney system to correct.
Below is a description of the common design problems which may lead to smoking problems.
Damper is Closed
Check to see if the damper is open or functioning properly. More people overlook
this than you might think!
Inadequate Air Supply
Open a window or door as close to the fireplace as possible. If the smoking lessons
or stops when the door or window is open, the problem is inadequate air supply.
Homes today are designed to be as air tight as possible. The flow of air up the
chimney cannot exceed the flow of air into the house. All air removed from the room
during the burning process must be replaced by fresh outside air. This air would
normally enter the house through small cracks in the doors and windows.
Many fireplaces being installed in apartments now come with an “outside air
source”. A lever or handle will usually be found in or near the fireplace.
This can be opened to allow fresh air into the firebox to replace the room air being
used. If your fireplace does not have an outside air source one can be installed
in masonry fireplaces.
Fireplace Opening is too Large
This problem typically allows the fire to burn comfortably for a while, but the
room will become smoky after a time. The fireplace opening should be sized based
upon a relationship with the chimney flue. An ideal fireplace opening would be no
more than ten times the cross sectional area of the chimney flue. For example if
the inside dimensions of the flue are 10 x 10 equalling 100 square inches, then
the fireplace opening should not exceed 10 times this or 1000 square inches.
If a fireplace opening is to large it will allow more air into the fireplace than
the flue can exhaust. Fortunately, this is an easy problem to fix. By installing
a fireproof shield at the top of the fireplace opening, the effective opening can
be reduced. Glass doors could also be used.
The Chimney Flue is Obstructed
Extinguish the fire and look for obstructions. Birds nests are commonly found in
chimneys and may often be large enough to restrict flow. Soot and creosote can plug
or restrict the airflow of others. If the chimney is older, fallen brick or mortar
may be obstructing the flue. Any obstructions must be removed. A blocked chimney
is a fire hazard and should never be used until completely cleaned and inspected.
Chimneys blocked as a result of structural failure should be condemned and rebuilt.
Improper Construction or Design
It is possible that a masonry chimney was poorly designed. If your fireplace consistently
smokes and none of the ideas presented above work, It may be that your chimney has
design flaws. Please contact our office about this.
Occasional smoking problems
Occasional smoking problems are often the most difficult to diagnose , but most
are simple to correct, if the problem can be tracked down! A brief description of
the most common occasional smoking problems follows. With experimentation and patience
we can discover the problem and you may at last enjoy the fire you long to!
Temperature
If the temperature outside is fairly close to the inside temperature and their is
a high pressure cell in the area, you probably do not have enough air pressure in
the house to maintain a draft. The only solution here is to wait for the weather
to change.
Competing Vents from other Appliances
Check for the existence of competing vents. Kitchen and bathroom fans, or chimneys
for other fireplaces or stoves may overpower your chimneys draft by drawing the
air they need through the “smoking” chimney. This problem can be solved
by ensuring each vent has adequate air flow. If the house is two or more stories,
hot air rising and escaping from the top story can reduce the air pressure of the
ground floor, and pull air in from the outside, even down the chimney.
Wood Supply
Check your wood. Excess moisture in the wood can be one problem. Dense woods which
are hard to light can cause an initially cool fire which can result in poor draft
and excessive smoke.
Chimney Height
Measure the effective height of your chimney. This includes only the part of the
chimney that is above the point the woodstove is vented into the chimney or the
point above the firebox of a fireplace. Any chimney with an effective height of
less then 10 feet will generally cause problems. The chimney or flue pipe must extend
out of the top of the roof 3 feet as well as being 2 feet higher than anything within
10 feet.
Chimney Caps
Check for obstructions that might form as downdraft. Roof lines, trees, hills, or
nearby structures can all cause downdraft problems. When the wind blows over and
down around them, the downdraft simply blows down the flue, sending the smoke into
the house. A chimney cap will reduce the effects of those rear vertical blasts of
wind.
Other Types of Smoking Problems
Unused Fireplace Smokes while Another is being Used
Often a fireplace will smoke while another in the house is being used due to the
“inadequate air flow” idea presented above. This problem can at times
be easily solved by raising the flue height of the offending fireplace 6-12 inches.
This is an inexpensive job when performed by our company and will in most cases
solve the problem.
Smoking When Stove or Glass Doors are Opened
This is most often cured by opening the doors slowly, allowing for the air flow
to adjust in the firebox. Opening the draft fully several minuets before opening
the doors will raise the temperature and eliminate a lot of the smoke.
Smoking Problems when Household Doors are Opened
A door opened or closed rapidly can result in a change in your homes air pressure,
causing the draft to briefly stop or even reverse. An outside air source would solve
this type of problem.