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Chimney Installation
CHIMNEY
Your wood furnace may be hooked up with a factory
built or masonry chimney, matching the diameter of the
exhaust. If you are using a factory built chimney, it must
comply with UL 103 or CSA-B365 standard; therefore it must
be a Type HT (2100°F). It is extremely important that it be
installed according to the manufacturer’s specifications.
If you are using a masonry chimney, it is important that it be
built in compliance with the specifications of the National
Building Code. It must be lined with fire clay bricks, metal or
clay tiles sealed together with fire cement. (Round flues are
the most efficient).
The interior diameter of the chimney flue must be identical to the furnace smoke exhaust. A flue which is too
small may cause draft problems, while a large flue favors rapid cooling of the gas, and hence the build-up of
creosote and the risk of chimney fires. Note that it is the chimney and not the furnace which creates the draft
effect; your furnace’s performance is directly dependent on an adequate draft from your chimney.
Do not connect this unit to a chimney flue serving another appliance.
The following recommendations may be useful for the installation of your chimney:
•
It must rise above the roof at least 3’ (0.9m) from the uppermost point of contact.
•
The exterior portion should be double or triple wall pipe to ensure proper draft.
•
The chimney must exceed any part of the building or other obstruction within a 10’ (3.04m) distance by a
height of 2’ (0.6m).
•
Installation of an interior chimney is always preferable to an exterior chimney. The interior chimney will be
hotter than an exterior chimney that is being cooled by the ambient air outside the house. Therefore the gas
which circulates will cool slower, thus reducing the build-up of creosote and the risk of chimney fires.
•
The draft caused by the tendency for hot air to rise will be increased with an interior chimney.
•
Using a fire screen at the extremity of the chimney requires regular inspection in order to insure that it is not
obstructed thus blocking the draft, and it should be cleaned when used regularly.
IMPORTANCE OF PROPER DRAFT
Draft is the force which moves air from the appliance up
through the chimney. The amount of draft in your chimney
depends on the length of the chimney, local geography,
nearby obstructions and other factors. Too much draft may
cause excessive temperatures in the appliance. Inadequate
draft may cause back puffing into the room and ‘plugging’
of the chimney. Inadequate draft will cause the appliance
to leak smoke into the room through appliance and chimney
connector joints. An uncontrollable burn or excessive
temperature indicates excessive draft. Do not operate with
the flue draft exceeding .06 water column/14.93 Pascals. The
draft can be checked with a draft gauge or manometer.
Take into account the chimney’s location to insure it is not too
close to neighbors or in a valley which may cause unhealthy
or nuisance conditions.
MASONRY CHIMNEY
Ensure that a masonry chimney meets the minimum standards
of the National Fire Protection Association (NFPA) by having it
inspected by a professional. Make sure there are no cracks,
loose mortar or other signs of deterioration and blockage.
Have the chimney cleaned before the furnace is installed
and operated. When connecting the furnace through a
combustible wall to a masonry chimney, special methods
are needed as explained in the “Combustible Wall Chimney
Connector Pass-Throughs” Section.
