CARBON MONOXIDE POISONING HAZARD
Failure to follow the steps outlined below for each appliance
connected to the venting system being placed into operation
could result in carbon monoxide poisoning or death.
The following steps shall be followed for each appliance
connected to the venting system being placed into operation,
while all other appliances connected to the venting system are
not in operation:
1. Seal any unused openings in venting system.
2. Inspect the venting system for proper size and horizontal
pitch, as required in the National Fuel Gas Code, ANSI
Z223.1-2002/NFPA 54-2002 or the CSA B149.1, Natu-
ral Gas and Propane Installation Code and these instruc-
tions. Determine that there is no blockage or restriction,
leakage, corrosion and other deficiencies, which could
cause an unsafe condition.
3. As far as practical, close all building doors and windows
and all doors between the space in which the appli-
ance(s) connected to the venting system are located and
other spaces of the building.
4. Close fireplace dampers.
5. Turn on clothes dryers and any appliance not connected
to the venting system. Turn on any exhaust fans, such as
range hoods and bathroom exhausts, so they are operat-
ing at maximum speed. Do not operate a summer
exhaust fan.
6. Follow the lighting instructions. Place the appliance
being inspected into operation. Adjust the thermostat so
appliance is operating continuously.
7. Test for spillage from draft hood equipped appliances at
the draft hood relief opening after 5 minutes of main
burner operation. Use the flame of a match or candle.
8. If improper venting is observed during any of the above
tests, the venting system must be corrected in accordance
with the National Fuel Gas Code, ANSI Z223.1-
2002/NFPA 54-2002 and/or CSA B149.1, Natural Gas
and Propane Installation Codes.
9. After it has been determined that each appliance con-
nected to the venting system properly vents when tested
as outlined above, return doors, windows, exhaust fans,
fireplace dampers and any other gas-fired burning appli-
ance to their previous conditions of use.
Vent system or vent connectors may need to be resized. For any
other appliances when resizing vent systems or vent connectors,
system or connector must be sized to approach minimum size as
determined using appropriate table found in the NFGC or NSC-
NGPIC.
COMBUSTION-AIR AND VENT PIPING
General
Combustion-air and vent pipe, fittings, primers, and solvents must
conform to American National Standards Institute (ANSI) stan-
dards and American Society for Testing and Materials (ASTM)
standards. See Table 6 for approved materials for use in the U.S.A.
In Canada construct all combustion-air and vent pipes for this
furnace of CSA or ULC listed schedule-40 PVC, PVC-DWV or
ABS-DWV pipe and pipe cement. SDR pipe is NOT approved in
Canada.
See Table 7 for maximum pipe lengths and Fig. 36, 37, 38, 39, and
40 for exterior piping arrangements.
NOTE: Furnace combustion-air and vent pipe connections are
sized for 2-in. pipe. Any pipe size change should be made outside
furnace casing in vertical pipe. (See Fig. 32.) This allows proper
drainage of vent condensate.
Combustion-air and vent pipes must terminate together in same
atmospheric pressure zone, either through roof or sidewall (roof
termination preferred), using accessory termination kit. See Table
5 for required clearances.
Furnace combustion-air and vent pipe connections must be at-
tached as shown in Fig. 33. Combustion-air intake plug fitting and
inducer housing alternate vent cap may need to be relocated in
some applications.
Fig. 32—Combustion-Air and Vent Pipe Diameter
Transition Location and Elbow Configuration
A93034
FURNACE
PIPE DIAMETER
TRANSITION IN
VERTICAL SECTION
NOT IN
HORIZONTAL
SECTION
Table 5—Combustion-Air and Vent Pipe
Termination Clearances
LOCATION
CLEARANCE (FT)
U.S.A. Canada
Above grade level or above
anticipated snow depth
11†
Dryer/Water heater vent See Note 5 See Note 5
From plumbing vent stack 33
From any mechanical fresh air intake See Note 4 6
For furnaces with an input capacity of
100,000 Btuh or less—from any non-
mechanical air supply (windows or doors
which can be opened) or combustion-air
opening
11
For furnaces with an input capacity greater
than 100,000 Btuh —from any non-
mechanical air supply (windows or doors
which can be opened) or combustion-air
opening
13
From service regulator vent, electric and
gas meters and relief equipment
See Note 6 See Note 6
Above grade when adjacent to public
walkway
See Note 3 See Note 3
† 18 in. above roof surface in Canada.
NOTES:
1. If installing 2 adjacent furnaces, refer to Multiventing and Vent Terminations
section for proper vent configurations.
2. When locating combustion-air and vent terminations, consideration must be
given to prevailing winds, location, and other conditions which may cause
recirculation of the appliance’s own flue products or the flue products of
adjacent vents. Recirculation can cause poor combustion, inlet condensate
problems, and accelerated corrosion of heat exchangers.
3. Vent termination can not terminate less than 2 ft horizontal and 7 ft above
public walkway or where condensate vapor or droplets may be a hazard.
4. Vent termination must be at least 3 feet above any forced draft inlets within
10 feet horizontal. Vent termination must be at least 3 feet horizontal from
other direct vent appliances intake unless otherwise specified by manufac-
turer.
5. 3 ft radius of furnace vent air-intake terminal and 1 ft horizontally from
vertical centerline of furnace vent air-intake terminal.
6. Above a meter/regulator within 3 feet horizontally of vertical centerline of
meter/regulator vent outlet to a maximum vertical distance of 15 feet.
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