Harman Stove Company TL300, Installation & Operating Manual

10

Harman TL300

venting

Chimney Connectors and Chimneys

Draft

Draft is widely misunderstood.  It is important that you, 

the stove operator, realize that draft is a variable 

effect

, 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 

gases rising up the chimney, creating a pressure difference 

between the inside of your home and the outside air.  It con-

tinually moves fresh combustion air into the stove, and hot 

exhaust gases out of the stove; without this constant flow, 

the fire will go out.

Other factors, such as barometric pressure, winds, the 

tightness of the home, the total inside chimney volume, 

chimney height and the presence of venting devices such 

as exhaust fans also play a role in maintaining an adequate 

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 the exhaust gases. Introducing 

outside air directly to the stove may help remedy a low 

draft problem. Some signs of inadequate draft are smoking, 

odor, difficulty in maintaining the fire, and low heat output.  

Overdraft can be caused by a very tall chimney even if it 

is the recommended size, and can cause overfiring of your 

stove. Signs of an overdraft include rapid fuel consumption, 

inability to slow the fire, 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.

When installed and operated according to this manual, the 

TL300 will produce enough hot gases to keep the chimney 

warm so that adequate draft is maintained throughout the 

burn cycle.

Chimney Connectors

In general, following these guidelines will ensure compli-

ance with all national and provincial codes; prior to begin-

ning your installation, check with your local building code 

official(s)  regarding  any  additional  local  requirements  or 

regulations which may influence the design and placement 

of your venting system. 

The Harman TL300  may be installed with (.6 mm) 24 

gauge chimney connector pipe. The size of the connector 

should correspond to the size of the flue collar opening.  Do 

not use makeshift components. 

No part of the chimney connector may pass through an attic 

or roof space, closet or other concealed space, or through a 

floor or ceiling. Whenever possible, avoid passing the connec-

tor through a combustible wall; if you must, use an approved 

wall pass-through, described later in this section. 

Assemble the connector beginning at the flue collar, with 

the crimped ends pointing towards the stove (to keep debris 

and creosote flakes inside the system).  Each joint, including 

the one to the stove’s flue 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" (32 

mm) overlap is required at each joint, including the flue collar 

attachment.  No more than two 90 degree elbows should be 

used, and the total length of connector should not exceed 10 

feet (3m) All horizontal runs of connector must have a mini-

mum upward slope of 1/4 inch per foot (20 mm per meter).

Wall Pass-thrus

Occasionally it is necessary to pass the chimney connector 

through a combustible wall to reach the chimney.  Depending 

on your local building codes, and the pertinent provincial or 

national codes, there are several choices for accomplishing 

this safely. Before beginning your installation, contact local 

officials,  and  also  the  chimney  connector  and  chimney 

manufacturer for specific requirements.

Canada.  

Three methods are approved by the Canadian 

Standards Association.  The  diagram  shows  one  method 

requiring an 18" (460 mm) air space between the connector 

and the wall. It allows use of one or two covers as described in 

the diagram. The other two 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 Association) 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"(305 mm) around 

the entire chimney connector, and fill it with brick masonry 

which is at least 3.5"(90 mm) thick.  A fireclay liner, minimum 

3/8" (9 mm) wall thickness must run through the brick wall 

to the chimney liner (but not beyond the inner surface of the 

liner). It must be cemented in place with refractory cement.  

This  method  is  illustrated.  For  details  on  the  other  three 

options, refer to the most recent edition of the NFPA 211 

code.