The Chimney System
Soot and Creosote - Formation and Need for Removal
When wood is burned slowly, it produces tar and other organic vapors, which combine with expelled moisture to form soot or creosote. The soot and creosote vapors condense in the relatively cool chimney flue of a slow burning fire. As a result, soot or creosote residue accumulates on the flue lining. When ignited, this soot or creosote can result in an extremely hot fire. The chimney connector and chimney should be inspected at least once every two months during the heating season to determine if a soot or creosote
Checking your chimney and chimney connector more fre- quently, especially while you are getting used to your stove, is recommended. To inspect this system, let the stove cool. Using a flashlight and mirror, check the interior of the chimney connector, and the chimney itself.
To clean deposits from the surface of the connector, use a stiff wire brush after dismantling the connector assembly. To clean the chimney, use a specially designed brush sized to fit your particular flue opening, or call an established chimney cleaning service.
At the end of the heating season, perform a thorough examina- tion of your chimney system, and have it repaired if necessary.
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 continually 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 airtightness 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. In some cases, a window may need to be left open, or some other source of fresh air provided, to keep the appli- ance operating properly. 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 quickly.
Some signs of inadequate draft are smoking, odor, diffi- culty in maintaining the fire, and low heat output. Overdraft can be caused by a very tall chimney even if it is the recom- mended 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
TLC 2000 Coal Stove | 17 |
guidelines in this manual, including size, type, and height to avoid draft problems.
When installed and operated according to this manual, the TLC 2000 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 beginning your installation, check with your local building code official to check on additional local regulations which may influence the design and placement of your venting system.
The Harman TLC 2000 may be installed with (150 mm) 24 gauge chimney connector pipe. Size of the connector should correspond to the size of the flue 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 floor or ceiling. Whenever possible, avoid passing the connector through a combustible wall; if you must, use an approved wall
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
mm)overlap is required at each joint, including the flue col- lar 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 upward slope of 1/4"(6 mm) per foot (20 mm per meter).
Wall Pass-throughs
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 manu- facturer for specific requirements.
Canada. Three methods are approved by the Canadian Standards Association. The diagram shows one method re- quiring 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.