INSTALLATION CONSIDERATIONS
21
ensure that all piping and connections possess adequate
structural integrity and support to prevent flue pipe separa-
tion, shifting, or sagging during furnace operation.
Dual Certification: Non-Direct/Direct Vent (90%
Furnaces Only)
The 90% furnace is dual certified and may be installed as a
non-direct vent (single pipe) or direct vent (dual pipe) appli-
ance. A
non-direct vent
installation requires only a vent/
flue pipe. A
direct vent
installation requires both a vent/
flue pipe and a combustion air intake pipe. Refer to the ap-
propriate section for details concerning piping size, length,
number of elbows, furnace connections, and terminations.
WARNING
T
O AVOID BODILY INJURY, FIRE OR EXPLOSION, SOLVENT CEMENTS MUST BE
KEPT AWAY FROM ALL IGNITION SOURCES (I.E., SPARKS, OPEN FLAMES, AND
EXCESSIVE HEAT) AS THEY ARE COMBUSTIBLE LIQUIDS.
A
VOID BREATHING
CEMENT VAPORS OR CONTACT WITH SKIN AND/OR EYES.
Precautions should be taken to prevent condensate from
freezing inside the vent/flue pipe and/or at the vent/flue pipe
termination. It is our recommendation that all vent/flue piping
exposed to temperatures below 35°F for extended periods
of time should be insulated with 1/2” thick closed cell foam.
Also all vent/flue piping exposed outdoors in excess of the
terminations shown in this manual (or in unheated areas)
should be insulated with 1/2” thick closed cell foam. Inspect
piping for leaks prior to installing insulation.
The following bullets and diagram describe the restrictions
concerning the appropriate location of vent/flue pipe and com-
bustion air intake pipe (when applicable) terminations. Re-
fer to the installation instructions for specific details on ter-
mination construction.
•
All terminations must be located at least 12 inches
above ground level or the anticipated snow level.
•
Vent terminations must terminate at least 3 feet above
any forced air inlet located within 10 feet.
NOTE:
This provision does not apply to the combus-
tion air intake termination of a direct vent application.
•
The vent termination of a
non-direct
vent
application
must terminate at least 4 feet below, 4 feet horizon-
tally from, or 1 foot above any door, window, or gravity
air inlet into any building.
•
The vent termination of a
direct vent
application must
terminate at least 12 inches from any opening through
which flue gases may enter a building (door, window,
or gravity air inlet).
•
The vent termination of vent pipe run vertically through
a roof must terminate at least 12 inches above the
roof line (or the anticipated snow level) and be at least
12 inches from any vertical wall (including any antici-
pated snow build up).
•
A vent termination shall not terminate over public walk-
ways or over an area where condensate or vapor could
create a nuisance or hazard or could be detrimental
to the operation of regulators, relief valves, or other
equipment.
•
The combustion air intake termination of a direct vent
application should not terminate in an area which is
frequently dusty or dirty.
NOTE:
In Canada, the B149 Fuel Gas Code takes prece-
dence over the preceding termination restrictions.
Direct Vent Installations
On
upflow
units secure the combustion air intake pipe di-
rectly to the air intake coupling. On
counterflow
units se-
cure the combustion air intake pipe to the air intake cou-
pling using the rubber coupling and worm gear hose clamps
provided with the unit. The counterflow rubber coupling al-
lows service removal of air intake piping internal to the fur-
nace blower compartment. The combustion air intake pipe
can also be secured directly to the counterflow unit air in-
take pipe coupling.
Non-Direct Vent Installations
A minimum of one 90° elbow must be installed on the com-
bustion air intake “coupling” to guard against inadvertent
blockage.
WARNING
T
HE RUBBER ELBOW IS NOT DESIGNED TO SUPPORAT A LOAD.
W
HEN THE
RUBBER ELBOW IS MOUNTED EXTERNALLY TO THE FURNACE CABINET,
EXTREME CARE MUST BE TAKEN TO ADEQUATELY SUPPORT FIELD-SUPPLIED
VENT/FLUE PIPING, AS DAMAGE CAN RESULT IN LEAKS CAUSING BODILY
INJURY OR DEATH DUE TO EXPOSURE TO FLUE GASES, INCLUDING CARBON
MONOXIDE.
CAUTION
B
E SURE NOT TO DAMAGE INTERNAL WIRING OR OTHER COMPONENTS WHEN
REINSTALLING COUPLING AND SCREWS.
Vent/Flue Pipe Lengths and Diameters
Refer to the following tables for applicable length, elbows,
and pipe diameter for construction of the vent/flue pipe sys-
tem of a non-direct vent installation. In addition to the vent/
flue pipe, a single 90° elbow must be secured to the com-
bustion air intake to prevent inadvertent blockage. The tee
or elbows used in the vent/flue termination must be included
when determining the number of elbows in the piping sys-
tem.
