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14
Installation & Service Manual
2 Venting
The distance of the vent terminal from adjacent
build ings, windows that open and building open ings MUST
comply with the latest edition of the National Fuel Gas Code,
ANSI Z223.1, in Canada, the latest edition of CGA Standard
B149 In stal la tion Code for Gas Burn ing Appliances and
Equipment.
Vent connection is made directly to the top of the
ap pli ance. This appliance is designed with a built-in draft
diverter. No additional external draft hood is re quired. The
connection from the appliance vent to the common vent or
chimney must be made as direct as possible.
A Conventional Negative Draft
Venting System
The negative draft in a conventional vent in stal la tion must be
within the range of a negative 0.02 to 0.05 inches water column
to ensure proper operation. All draft read ings are made while
the appliance is in stable op er a tion (approximately 2 to 5
minutes).
Multiple appliance installations with combined vent ing or
common venting with other negative draft ap pli anc es require
that each appliance must have draft with in the proper range. If
the draft mea sured above the appliance’s built-in draft diverter
ex ceeds the specified range in a dedicated chimney for a single
appliance installation or in combined venting with other
negative draft appliances, a baro met ric damper must be in -
stalled to control draft.
Figure 2-1_Conventional Negative Draft Vertical Venting
TABLE - 2A
VENT PIPE SIZES
Input Btu/hr Flue Size
90,000 5"
135,000 6"
180,000 7"
199,999 7"
225,000 7"
270,000 8"
315,000 8"
360,000 9"
399,999 10"
500,000 10"
On a conventionally vented, negative draft ap pli ance, the
connection from the vent to the chimney or vent termination on
the outside of the building MUST be made with listed Type “B”
double wall (or equivalent) vent connectors and must be direct
as possible with no reduction in diameter. Use the National Fuel
Gas Code venting tables for dou ble wall vent to properly size all
vent connectors and stacks. The Type “B” vent and accessories,
such as firestop spacers, thim bles, caps, etc., MUST be installed
in accordance with the manufacturer’s list ing. The vent
connector and firestop must provide correct spacing to
combustible surfaces and seal to the vent connector on the upper
and lower sides of each floor or ceiling through which the vent
connector passes.
Any vent materials used must be listed by a na tion al ly
recognized test agency for use as vent ma te ri al.