
16 Harman Oakwood
ChimneyConnectorsandChimneys
Draft
Draftiswidelymisunderstood. Itisimportantthatyou,
thestoveoperator,realizethatdraftisavariableeffect,not
a given quantity. Stoves and chimneys do not have draft,
yet draft is the key to your stove’s performance.
Draft is a force, produced by an operating stove and
the chimney to which it is attached. It is created by hot
gasesrisingupthechimney, creatinga pressuredifference
between the inside of your home and the outside air. It
continuallymovesfreshcombustionairintothestove,and
hot exhaust gases out of the stove; without this constant
ow, the re will go out.
Other factors, such as barometric pressure, winds, the
airtightnessof thehome,thetotalinsidechimneyvolume,
chimney height and the presence of venting devices such
asexhaustfansalsoplaya rolein maintaininganadequate
draft. Low barometric pressures, super insulated homes
and exhaust fans can reduce draft; winds can play havoc
with draft; and too large or too small a chimney volume
can cause reduced draft due to the excessive cooling
or not enough room to vent exhaust gases. Introducing
outside air directly to the stove may help remedy a low
draft problem. Some signs of inadequate draft are smok-
ing, odor, difculty in maintaining the re, and low heat
output. Overdraft can be caused by a very tall chimney
even if it is the recommended size, and can cause overr-
ingofyourstove. Signsofan overdraftincluderapid fuel
consumption, inability to slow the re, and parts of the
stove or chimney connector glowing red. It is important
that you follow the chimney guidelines in this manual,
including size, type, and height to avoid draft problems.
Wheninstalledand operatedaccordingto thismanual,
the Oakwood will produce enough hot gases to keep
the chimney warm so that adequate draft is maintained
throughout the burn cycle.
ChimneyConnectors
In general, following these guidelines will ensure
compliancewithallnationalandprovincialcodes;priorto
beginning your installation, check with your local build-
ing code ofcial to check on additional local regulations
which may inuence the design and placement of your
venting system.
The Harman Oakwood may be installed with a mini-
mum (.6 mm) 24 gauge chimney connector pipe. The size
of the connector should correspond to the size of the ue
collar opening. Do not use makeshift compromises. No
part of the chimney connector may pass through an attic
or roof space, closet or other concealed space, or through
a oor or ceiling. Whenever possible, avoid passing the
connector through a combustible wall; if you must, use
an approved wall pass-through, described later in this
section.
Assemble the connector beginning at the ue collar,
with the crimped ends pointing towards the stove (to
keep debris and creosote akes inside the system). Each
joint, including the one to the stove’s ue collar and the
one to the chimney itself should be secured with at least
three sheet metal screws. Screws may be a maximum of
3 inches apart. A 1-1/4" (30 mm) overlap is required at
each joint, including the ue collar attachment. No more
than two 90 degree elbows should be used, and the total
length of connector should not exceed 10 feet (3 m). All
horizontal runs of connector must have a minimum up-
ward slope of 1/4"(6 mm) per foot (20 mm per meter).
Chimneyconnectorshouldcorrespondtothesizeofthe
ue collar opening. Do not use makeshift compromises.
No part of the chimney connector may pass through an
attic or roof cemented in place with refractory cement.
WallPass-throughs
Occasionally it is necessary to pass the chimney con-
nector through a combustible wall to reach the chimney.
Dependingonyourlocalbuildingcodes,andthepertinent
provincial or national codes, there are several choices
for accomplishing this safely. Before beginning your
installation, contact local ofcials, and also the chimney
connector and chimney manufacturer for specic require-
ments.
Canada. ThreemethodsareapprovedbytheCanadian
Standards Association. The diagram on the next page
shows one method requiring an 18"(450 mm) air space
between the connector and the wall. It allows use of
one or two covers as described in the diagram. The two
other methods are described in detail in the current issue
of CAN/CSA B365, the national standard.
United States In the U.S., the national code is NFPA
211. While many localities adopt this standard, be sure
to check with local authorities before beginning your
installation.
The NFPA (National Fire Protection Agency) permits
four methods for passing through a combustible wall. A
commonly used method to pass through a wall directly to
a masonry chimney is to clear a minimum 12"(300 mm)
around the entire chimney connector, and ll it with brick
masonry which is at least 3.5"(90 mm) thick. A reclay
liner, minimum 3/8" (9 mm) wall thickness must run
through the brick wall to the chimney liner (but not be-
yond the inner surface of the liner). It must be cemented
inplacewithrefractorycement. Thismethodisillustrated
on the next page. For details on the other three options,
refer to the most recent edition of the NFPA 211 code.
VENTING