Vermont Casting 43LDVR, 39LDVR Twist Lock Pipes, How to Use the Vent Graph, Example A, Example B

LDVR Series Direct Vent Gas Fireplace

Twist Lock Pipes

When using CFM Corporation twist-lock pipe it is not necessary to use sealant on the joints. The only areas of the venting system that need to be sealed with high temperature silicone sealant are the sliding joints of any telescopic vent section used in the system.

To join the twist lock pipes together, simply align the beads of the male end with the grooves of the female end, then while bringing the pipe together, twist the pipe until the flange on the female end contacts the external flange on the male end. It is recommended that you secure the joints with three (3) sheet metal screws, however this is not mandatory with twist lock pipe.

To make it easier to assemble the joints we suggest putting a lubricant (Vaseline or similar) on the male end of the twist lock pipe prior to assembly.

Male End Female End

Screw Holes TWL100

Fig. 12 Twist-lock pipe joints.

How to Use the Vent Graph

The vent chart should be read in conjunction with the following vent installation instructions to determine the relationship of the vertical and horizontal dimensions of the vent system.

1.Determine the height of the center of the horizontal vent pipe exiting through the outer wall. Using this dimension on the Sidewall Vent Graph (Fig. 13) locate the point intersecting with 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 fireplace is 11’ (3.4 m) the horizontal run to the face of the outer wall must not exceed 14’ (4.3 m).

Example B:

If the vertical dimension from the floor of the unit is 7’ (2.14 m), the horizontal run to the face of the outer wall must not exceed 8¹⁄₂’ (2.6 m).

30
29
28
27
26
25																			Vertical
24																		tothe
23
22
21																		center of thehorizontalventpipe	dimension fromtheflooroftheunit
7
20
19
18
17
16
15
14
13
													eg:	A
12
11
10
9
8
6								eg:		B
5
4
3
3	4	5	6	7	8	9	10		11 12		13 14	15 16			17 18	19	20

Horizontal dimension from the outside face of the

wall to the center of the fireplace vent flange

Sidewall vent graph showing the relationship between vertical

and horizontal dimensions for a Direct Vent flue system.

Fig. 13 Sidewall venting graph. (Dimensions in feet)

Rear Wall Venting Applications

When installed as a rear vent unit this appliance may be vented directly to a termination located on the rear wall behind the appliance.

•Only CFM Corporation venting components are approved to be used in these applications. (Refer to “Venting Components” listed for different installation requirements)

•The maximum horizontal distance between the rear of the appliance (or end of the transition elbow in a corner application) and the outside face of the rear wall is 20” (508mm). (Fig. 14)

•Only one 45° elbow is allowed in these installations.

•Minimum clearances between vent pipe and com- bustible materials are as follows:

Top - 2” (51 mm)

Sides - 1” (25 mm)

Bottom - 1” (25 mm)

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