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915SB: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
36
A13078A
Fig. 49 – Alberta and Saskatchewan Vent Termination
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.
Any change in diameter to the pipe must be made as close to the furnace
as reasonably possible. See
.
The Maximum Vent Length for the vent and combustion air pipe (when
used) is determined from the Maximum Equivalent Vent Length in
minus the number of fittings multiplied by the deduction for
each type of fitting used from
.
A93034
Fig. 50 – Combustion Air and Vent Pipe Diameter Transition
Location and Elbow Configuration
A170122A
Fig. 51 – Recommended Combustion Air Inlet Moisture Trap
Recommended Combustion Air Inlet Moisture Trap
Recommended to prevent moisture from trickling into the furnace
vestibule, a trap can be installed in the intake air pipe near the furnace.
To prevent moisture, connecting a drain line to the trap is recommended
as trace amounts of moisture will evaporate into the intake air stream. If
the combustion air inlet is located near a moisture exhaust duct, or there
are other concerns of excessive moisture being drawn into the
combustion air inlet, it is encouraged to connect a drain line to the trap.
The trap can be constructed from a running tee of the same diameter of
the intake air pipe with
EITHER
a removable cap attached to a 6-inch
long pipe connected to the tee or the External Vent Trap Kit to help
prevent contaminants from entering the furnace. See
The External Vent Trap Kit accessory may be used as a trap for the
combustion air inlet pipe if a large amount of moisture must be removed.
The drain line may be connected to the same drain as the furnace
condensate and the evaporator coil condensate line
ONLY
if the inlet air
OPTIONAL TERMINATION
BRACKET FOR 2-PIPE
TERMINATIONS
12-IN. (305 MM)
ABOVE ANTICIPATED
SNOW LEVEL
12 IN. (305 MM) MIN.
SEPARATION BETWEEN
BOTTOM OF COMBUSTION
AIR AND BOTTOM OF VENT.
12 IN. (305 MM) MIN. SEPARATION
BETWEEN BOTTOM OF
COMBUSTION AIR AND
BOTTOM OF VENT.
MAINTAIN 12 IN. (305 MM)
CLEARANCE ABOVE
HIGHEST ANTICIPATED
SNOW LEVEL OR GRADE,
WHICHEVER IS GREATER.
COMBUSTION-AIR
(ELBOW PARALLEL TO WALL)
OPTIONAL
BRACKET
COUPLING
OVERHANG
12 IN. (305 MM) MIN. GROUND
LEVEL OR ANTICIPATED SNOW LEVEL
EXHAUST
CLEARANCE TO OVERHANG PER CODE
NOTICE
!
OPTIONAL CONFIGURATION FOR COMBUSTION AIR INLET
PIPE
In applications where there is a risk of excessive moisture entering the
combustion air inlet pipe, a moisture trap may be added to the inlet pipe
to help prevent moisture from entering the furnace from the combustion
.
When sizing venting systems, the equivalent length of the optional
moisture trap (15 feet/5 M) must be taken into account.
FURNACE
PIPE DIAMETER
TRANSITION IN
VERTICAL SECTION
NOT IN
HORIZONTAL
SECTION
Representative drawing only, some models may vary in appearance.
TO CODE--APPROVED DRAIN OR CONDENSATE PUMP
Tee
Dry Well
Cap
(water tight
and removable)
Tee
Dry Well
Cap
(water tight
and removable)
Tee
Dry Well
Cap
(water tight
and removable)
Recommend “T” fitting with 4--inch minimum height standpipe (
A
) of same diameter or larger extending upward.
A
A
A