Vermont Casting WinterWarm Fireplace Insert or System The Chimney Connector, Sealing Requirements

Flue

Collar

Glass

Door

B	A	B
	C

United States		Canada
A. 16“	(410 mm)	18”	(457 mm)
B. 8” (203 mm)		8” (203 mm)
C. 40”	(1016 mm)	40”	(1016 mm)

NOTE: Measuring from the door opening of the insert to the fire- place opening adds 3¹⁄₂” (90mm) to the total depth of the hearth

protector.FP1086

Fig. 21 Unless your fireplace and hearth are constructed over a dirt floor (or unpainted concrete over dirt), you must use a floor protector that satisfies the above requirements.

The approved construction of a floor protector calls for 24 gauge galvanized sheet metal covered with a listed floor protector material that is at least 7/16” (11 mm) thick (such as Wonderboard® or Durock®). The floor protector may be covered with a noncombustible deco- rative material if desired. (Fig. 21)

Custom-made floor protectors may be used if they offer the same protection as the approved floor protector described in the preceding paragraph, which in testing was found to have a standard K value of 0.84. Custom- built floor protectors must have a K value equal to, or less than, 0.84, meaning that heat will transfer at the same rate or more slowly than the tested standard.

To calculate the thickness required for an alternate material to result in a K value of 0.84, first determine the alternate material’s K factor. This information should be available from your local building supply yard. Then, calculate the following formula:

(K factor
of alternate
material)		(Required thickness of
	X (7/16" [11mm]) =
(0.84)		alternate material)

Let’s use brick as an example, since it is a commonly used hearth material. Its K factor is 5.0.

(5.0)	X (7/16" [11mm]) = 2.6" (65mm)
(0.84)

WinterWarm Fireplace Insert or System

That is, when using brick for the hearth extension, the brick must be a minimum of 2.6” (65 mm) thick.

Once you know the K factor of a given material, you can use this same formula to calculate its required thickness for approved hearth protection.

NOTE: Any floor protector thicker than 9/16” (14mm) will require elevating the firechamber on a solid, ap- proved floor protector to provide enough clearance for the door to open. This in turn will require a higher fire- place opening to permit installation of the fire chamber.

The Chimney Connector

Connect your WinterWarm Fireplace Insert to the chimney flue with a “positive flue connection.” Such a connection provides a direct passageway for smoke and exhaust gases leading from the flue collar of the WinterWarm to the first chimney lining tile. Positive flue connections are required in many areas before an installation can be approved.

The chimney connector itself should have a minimum cross-sectional area of 50 square inches (320 square centimeters), equivalent to an 8” (203 mm) diameter

opening, and must be 24 gauge or heavier.

Sealing Requirements

It is important to seal off the flue completely from the room air for proper operation of your WinterWarm. There are three ways to accomplish this:

1.Install a CFM Corporation Flex Connector system;

2.Install a customized seal at the damper level;

3.Have your chimney professionally re-lined and con- nect the liner directly to the WinterWarm.

Of these three choices, the Flex Connector not only provides an effective seal but usually is the easiest to install.

The Flex Connector System

The Flex Connector bends the chimney connector through angled smoke chambers and narrow damper frames, and its Block-off plate makes a tight seal at the damper frame. (Fig. 22)

To determine the suitability of the Flex Connector for your fireplace, carefully examine the fireplace damper area. The damper opening must be unobstructed and must measure at least 5” x 14” (127 x 356 mm) to accommodate the Flex Connector and the Block-off Plates. An undersized opening, or an opening obstruct- ed by heat exchanger tubes or damper components, may prevent the Flex Connector from extending up to the flue or may be possible only after special work has been done.

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