What Kind of Chimney to Use, Chimney Size

Vermont Castings Defiant

What Kind of Chimney to Use

You must connect the Defiant to a code-approved masonry chimney with a flue liner, to a relined masonry chimney that meets local codes, or to a prefabricated metal chimney that complies with the requirements for Type HT chimneys in the Standard for Chimneys, Factory-Built, Residential Type and Building Heating Appliance, UL 103. Fig. 2 illustrates the two types. The chimney and chimney connector must be in good condition and kept clean.

If you use an existing masonry chimney, it must be inspected to ensure it is in a safe condition before the stove is installed. Your local professional chimney sweep, building inspector, or fire department official will be able to inspect the chimney or provide a referral to someone who can. See 'Chimney and Fireplace Hazards, in the appendix, for particulars.

A prefabricated double-

wall insulated chimney

A tile-lined masonry chimney

ST241

Fig. 2 Approved chimney types.

The chimney must extend at least 3' (900 mm) above the highest point where it passes through or past a roof, and at least 2' (600 mm) higher than any part of a building within 10' (3 m) horizontally. (Fig. 3)

For proper draft and good performance, any chimney used with a Defiant should extend at least 16 feet (5 m) above the flue collar of the stove.

	0 TO 10'
	2' Min.	0 TO 10'
	3'	0 TO 10'
	Min.
		2' Min.3'
		Min.
	Reference
	Point	AC617
		AC617
Fig. 3	The 2’-3’10’ Chimney Rule.
6

Masonry Chimneys

An inspection of the chimney must confirm that it has a lining. Do not use an unlined chimney. The chimney must have no cracks, loose mortar, other signs of deterioration, or blockage. Repair any defects before using the chimney with your stove.

Seal any unused openings in an existing masonry chimney with masonry to the thickness of the chimney wall, and repair the chimney liner. Openings sealed with pie plates or wallpaper are a hazard and must be sealed with mortar or refractory cement. In a chimney fire, flames and smoke may be forced out of these unused thimbles.

The chimney should be thoroughly cleaned before use.

Anewly-built masonry chimney must conform to the standards of your local building code or, in the absence of a local code, to a recognized national code. Masonry chimneys must be lined, either with code- approved masonry or pre-cast refractory tiles, stainless steel pipe, or a code-approved, “poured-in-place” liner. The chimney’s clean-out door must seal tightly. A loose or leaky clean-out door can weaken chimney draft to the stove, causing performance problems.

Prefabricated Chimneys

A prefabricated metal chimney must be one tested and listed for use with solid-fuel burning appliances to the High-Temperature (H.T.) Chimney Standard UL-103- 1985 (2100° F.) for the United States, and High Temperature (650˚C) Standard ULC S-629 for Canada.

DO NOT CONNECT THIS UNIT TO A CHIMNEY FLUE SERVING ANOTHER APPLIANCE.

Chimney Size

The Defiant is approved for venting into a masonry chimney with a nominal flue size of 8" x 8" (200 x 200

mm)or 8" x 12" (200 x 300 mm), and into a round flue with nominal flue size of 8" (200 mm). A Defiant with a 6" (150 mm) flue collar adapter is approved for venting into a masonry chimney with a nominal flue size of 8" X 8" (200 X 200 mm), and into a round flue with nominal flue size of 6" (150 mm).

NOTE: When installed with a 6" flue collar

adapter, the Defiant may not be operated with the front doors open.

Whatever the flue collar size, a Defiant may be vented into larger chimneys as well. However, chim- neys with liners larger than 8" x 12" (200 x 300 mm) may experience rapid cooling of smoke and reduction in draft, especially if the chimneys are located outside the home. These large chimneys may need to be insulated or have their flues relined for proper stove performance.