Vermont Casting BHDT36 installation instructions How To Use The Vent Graph, eg A, eg B

If a 90 degree elbow is used in the horizon- tal vent run (level height maintained) the maximum horizontal vent length is reduced by 36 inches. Fig. 15. This does not apply if the 90 degree elbows are used to increase or redirect a vertical rise.

The maximum number of elbow degrees in a system is 270º.

Sample:	1	-	90º
	2	-	45º
	3	-	45º
	4	-	90º
	Total		270º
			Fig. 15

Example: According to the vent chart the maximum horizontal vent length is 20' when the vertical height is 7.5' from fireplace base height. If one 90 degree elbow is required in the horizontal vent it must be reduced to 17'.

	84"
	2134mm	120"
		3048mm
90"	90¼ elbow=3'
2286mm
		Fig. 16

HOW TO USE THE VENT GRAPH

1.Determine the height of the centre of the horizontal vent pipe exiting through the outer wall. Using this dimension on the Sidewall Vent Graph (Fig. 17), locate the point it intersects with the slanted graph line.

2.From the point of this intersection, draw a vertical line to the bottom of the graph.

3.Select the indicated dimension, and position the fireplace in accordance with same.

EXAMPLE A:

If the vertical dimension from the floor of the unit is 11 feet (3352mm) the horizontal run to the face of the outer wall must not exceed 14 feet (4267mm).

EXAMPLE B:

If the vertical dimension from the floor of the unit is 7 feet (2133mm), the horizontal run to the face of the outer wall must not exceed 8-1/2 feet (2590mm).

VERTICAL SIDEWALL VENTING GRAPH

(Dimensions in Feet)

30
29
28		TOTHE	VERTICAL
27
26
25		CENTREOF	DIMENSION
24
23
22
21
20		THEHORIZONTAL	FROMTHEFLOOR
19
18
17
16
15
14
13		VENTPIPE	OFTHEUNIT
12	eg: A
11
10
9

8
7
	eg: B
6
5
4
3

34 5￿ 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Fig. 17

SEE PAGE 14 FOR VENTING

REQUIREMENTS FOR SNORKELS.

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