12
PREFERRED
Figure 4
TRANSITION NO LESS
THAN 45 DEGREES TO
HORIZONTAL PLANE TO
AVOID CREATING A WATER
TRAP IN VENT PIPING.
ACCEPTABLE
Figure 5
NO TRANSITION ON
HORIZONTAL PLANE,
THIS CREATES A
WATER TRAP AND
RESTRICTS FLUE
GASES
Figure 6
P
ROPER
V
ENT
/F
LUE
AND
C
OMBUSTION
A
IR
P
IPING
P
RACTICES
Adhere to these instructions to ensure safe and proper furnace
performance. The length, diameter, and number of elbows
of the vent/flue pipe and combustion air pipe (when
applicable) affects the performance of the furnace and must
be carefully sized. All piping must be installed in accordance
with local codes and these instructions.
Some models require the use of 3” pipe. Do not transition
from a 2” to 3” pipe in a horizontal section of pipe as this
may create a water trap.
Piping must be adequately secured and supported to prohibit
sagging, joint separation, and/or detachment from the
furnace. Horizontal runs of vent/flue piping must be supported
every three to five feet and must maintain a 1/4 inch per
foot downward slope, back towards the furnace, to properly
return condensate to the furnace’s drain system. Allowances
should be made for minor expansion and contraction due to
temperature variations. For this reason, particular care must
be taken to secure piping when a long run is followed by a
short offset of less than 40 inches.
Precautions should be taken to prevent condensate from
freezing inside the vent/flue pipe and/or at the vent/flue
pipe termination. All vent/flue piping exposed to freezing
temperatures below 35°F for extended periods of time must
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) must be insulated
with 1/2” thick closed cell foam. Inspect piping for leaks
prior to installing insulation.
T
ERMINATION
L
OCATIONS
NOTE:
Refer to
Location Requirements and Considerations
for combustion air contaminant restrictions.
The following bullets and diagram describe the restrictions
concerning the appropriate location of vent/flue pipe and
combustion air intake pipe (when applicable) terminations.
Refer to
Non-Direct Vent (Single Pipe) Piping
and
Direct Vent
(Dual Pipe) Piping
located in this section for specific details
on termination construction.
•
All terminations (flue and/or intake) must be located
at least 12 inches above ground level or the anticipated
snow level.
•
Vent terminations (non-direct and direct vent) must
terminate at least 3 feet above any forced air inlet
located within 10 feet.
NOTE:
This provision does not apply to the combustion
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 horizontally
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 anticipated
snow build up).
•
A vent termination shall not terminate over public
walkways 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.
