12
CAUTION
Do not terminate the combustion air in-
take where the air is often heavily con-
taminated with compounds containing
chlorine or fluorine. Common residen-
tial sources of such compounds include:
Swimming pools and swimming pool
pumps/filter
Clothes dryer vents
Remote air conditioning or heat pump
units (A refrigerant leak would con-
taminate the combustion air.)
Plumbing vent stacks
Bathroom or swimming pool exhaust
fans
Undried paint strippers, adhesives,
paints, varnishes, sealers, waxes, and
solvents. These are often used during
new construction or remodeling.
Various commercial and industrial pro-
cesses may also be sources of chlorine/
fluorine compounds.
Horizontal Vent/Intake Terminations
90°
Medium
Radius
Elbow
Vent
12" Min.
24" Max.
3" Min
.
Screen
12" Min.
Air Intake
24" Max.
Figure 6
Horizontal Vent Termination
Position the combustion air intake terminal away from
obstructions, above anticipated snow accumulations,
and at least 12 inches above grade, as shown in Figure
6.
The exhaust vent must penetrate the wall within the
shaded region as shown in Figure 6.
All exhaust vent and air intake terminal fittings must be
medium radius (1/4 bend DWV) 90 degree elbows.
To prevent unnecessary shutdown of furnace due to
pressure switch trips, always determine anticipated snow
accumulation level, and install the terminals accord-
ingly to prevent exhaust vent and air intake blockages
If installation above snow accumulation is required, add
additional elbows as shown in Figure 7. A 12 inch
minimum clearance between the air intake and the
highest anticipated snow level must be maintained. The
exhaust vent must penetrate the wall within the shaded
region as shown in Figure 7.
90°
Medium Radius
Elbow
12" Min.
Vent
24" Max.
3" Min.
12" Min. Above
Highest Anticipated
Snow Level
Air Intake
24" Max.
Screen
12" Min.
Figure 7
Horizontal Vent Termination Above
Anticipated Snow Level
Do not
point terminals into window wells, stairwells,
alcoves or other recessed areas. It is preferable for the
air intake to terminate on opposite or adjacent sides of
the structure from the dryer vent. If this is not practical,
maintain a 3 foot clearance (residential laundry) or a 10
foot clearance (commercial laundry).
Vertical Vent/lntake Terminations
If the vent and air intake pipes are to be run vertically
through the roof, they must extend at least 12 inches
above the roof line and shall be no closer than 12 inches
to any vertical wall. The vent pipe must extend at least
12 inches above the air intake. See Figure 8. In areas
where heavy snow accumulation is expected, these
distances will need to be increased. The vent and air
intake pipes must be made tight where they pass through
the roof with a proper flashing such as used with a
plastic plumbing vent.
Maintain at least a three foot clearance from the air
intake pipe to plumbing vent stacks.
