935SA: Installation, Start-up, Operating and Service Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
30
and for Ventilated Combustion Air/Non-Direct/1-Pipe system (see
). Contact Local code authorities for other requirements to and/or
exemptions from the National codes shown in the figures.
Roof termination is often preferred since it is less susceptible to damage
or contamination, is usually located away from adjacent structures, is
less prone to icing conditions, and it often has less visible vent vapors.
Sidewall terminations may require sealing or shielding of building
surfaces with a corrosive resistance material due to the corrosive
properties of combustion products from the vent system, as well as
protection of adjacent structures.
Roof termination is the recommended termination location. Roof
terminations provide better performance against sustained prevailing
winds. The roof location is preferred since the vent and combustion air
system is less susceptible to damage or contamination. The termination
is usually located away from adjacent structures or other obstacles such
as inside corners, windows, doors or other appliances. It is less prone to
icing conditions, and it often has less visible vent vapors.
Sidewall terminations may require sealing or shielding of building
surfaces with a corrosive resistance material due to the corrosive
properties of combustion products from the vent system, as well as
protection of adjacent structures.
When determining appropriate location for termination, consider the
following guidelines:
1. Comply with all clearance requirements stated (see
) per application.
2. The vent termination must be located at least 3 feet from an inside
corner and follow the clearance distances in the Inside Corner
Termination drawing.
3. Termination or termination kit should be positioned where vent
vapors will not damage plants/shrubs, air conditioning equipment
or utility meters.
4. Do not locate termination directly into prevailing winds.
Termination should be positioned so that it will not be affected by
sustained prevailing winds over 30 mph, wind eddy, such as inside
building corners, or by recirculation of flue gases, airborne leaves,
or light snow.
5. Termination or termination kit should be positioned where it will
not be damaged by or subjected to foreign objects such as stones,
balls, etc.
6. Termination or termination kit should be positioned where vent
vapors are not objectionable
.
Direct Vent / 2-Pipe System
Direct vent (2-pipe) vent and combustion air pipes must terminate
outside the structure. For references to vent clearances required by
National code authorities (see
). Allowable vent and combustion
).
Ventilated Combustion Air
The vent pipe for a Ventilated Combustion Air System must terminate
outdoors. For references to vent clearances required by National code
authorities (see
). Allowable vent terminations (see
). The
combustion air pipe terminates in a well-ventilated attic or crawl space.
).
The combustion air pipe cannot terminate in attics or crawl spaces that
use ventilation fans designed to operate in the heating season. If
ventilation fans are present in these areas, the combustion air pipe must
terminate outdoors as a Direct Vent System.
Non-Direct Vent / 1-Pipe System
The vent pipe for a Non Direct Vent (1-pipe) system must terminate
outdoors. References to vent clearances required by National Code
authorities (see
). Allowable vent terminations (see
).
A combustion air inlet pipe to the outdoors is not required for a
Non-Direct (single-pipe) Vent System. A 12-in. long section of pipe with
a tight radius 2-in. (51 mm) 90 degree elbow is required to be attached to
the furnace. (see
) This short inlet air pipe helps to ensure stable
combustion, as well as allow for sound attenuation. To aid sound
attenuation, point the inlet air pipe away from occupants. An extra elbow
and/or five feet of pipe may be used to accomplish the sound attenuation
function.
A13406
Fig. 42 – Combustion Air Pipe Attachment
Size the Vent and Combustion Air Pipes
General
Furnace combustion air and vent pipe connections are sized for 2-in. (50
mm ND) PVC/ABS DWV pipe. The combustion air and vent pipe
connections also accommodate 60 mm polypropylene venting systems
with outside diameters of approximately 60 mm (2-3/8 inches). Any pipe
diameter change should be made outside furnace casing in vertical pipe.
NOTICE
!
RECOMMENDED SUPPORT FOR VENT
TERMINATIONS
It is recommended that sidewall vent terminations in excess of 24
inches (0.6 M) or rooftop terminations in excess of 36 inches (1 M) in
vertical length be supported by
EITHER
the Direct Vent Termination
Kit (
) or by field-supplied brackets or supports fastened to the
structure.
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow the instructions outlined below for each appliance
being placed into operation could result in carbon monoxide poisoning
or death.
For all venting configurations for this appliance and other gas
appliances placed into operation for the structure, provisions for
adequate combustion, ventilation, and dilution air must be provided in
accordance with:
Current edition of
Section 9.3 NFPA 54/ANSI Z223.1 Air for
Combustion and Ventilation and applicable provisions of the local
building codes.
12" (256mm) minimum
to
60”(1524 mm) or
1 additional elbow maximum
CASING SIDE OR TOP ATTACHMENT
COMBUSTION AIR PIPE
(NON-DIRECT VENT FOR ALL MODELS EXCEPT MODULATING UNLESS
INSTALLED IN ATTIC OR CRAWL SPACE)