PAGE 15
HEIGHT
ROOF PITCH
ABOVE ROOF
FLAT TO 7/12
1.0 FT.
OVER 7/12 TO 8/12
1.5 FT.
OVER 8/12 TO 9/12
2.0 FT.
OVER 9/12 TO 10/12
2.5 FT.
BRACE TO ROOF
OVER 10/12 TO 11/12
3.3 FT.
AT TOP
OVER 11/12 TO 12/12
4.0 FT.
OVER 12/12 TO 14/12
5.0 FT.
OVER 14/12 TO 16/12
6.0 FT.
BRACE TO ROOF
OVER 16/12 TO 18/12
7.0 FT.
AT TOP AND
OVER 18/12 TO 20/12
7.5 FT.
MID POINT
OVER 20/12 TO 21/12
8.0 FT.
ROOF PITCH CHART
H. INSTALLATION
1. Vent Adaptor.
Attach vent adaptor at draft inducer collar. See figure 18 on page 18. Use Kit #
56111101 for DV 50-125 and Kit # 56111102 for DV 150-200, or equivalent.
WARNING:
Make sure that all vent pipe and connectors are secured because
unsecured vent pipe connections may loosen. This can allow combustion products to collect
in the structure, resulting in injury or death.
2. Vent Connector.
Install vent connectors without any dips or sags. Slope them upward from boiler at
least 1/4" per foot. To prevent sagging, at each joint support vent connectors and horizontal
portions using hangers, straps or equivalent. Seal all connections where vent connectors enter
chimney. See Figure 11 on page 13.
3. Vertical Vent
Install vent materials following their listing terms, manufacturer’s instructions, these
instructions and local codes. A gas vent passing through a roof must extend through roof
flashing, jack or thimble. It must terminate above the roof surface.(Ref. Figure 14 & 15)
I. EXISTING VENT CONSIDERATIONS
MASONRY CHIMNEYS PREVIOUSLY USED FOR VENTING EQUIPMENT SHOULD BE
SUITABLY PER NFGC STANDARD. Also provide an accessible clean out per the latest
revision of the NFGC, ANSI Z2231, AND NFPA 54.1
1. INSPECTION OF VENTS
A. Make sure existing vent or chimney is the proper size and construction for
appliances that will use it. The best way to do this is to size as if it were a new installation.
Compare the existing vent to your calculations and make necessary corrections.
