F97CMN and G97CMN: 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.
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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. 46 – Combustion Air and Vent Pipe Diameter Transition
Location and Elbow Configuration
A13078
Fig. 47 – Alberta and Saskatchewan Vent Termination
Recommended Combustion Air Inlet Moisture Trap
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
trap drain and the evaporator coil drain empty into an open segment of
. When using the External Vent Trap Kit,
refer to those instructions for proper drain connections.
The tee may also be connected to the intake air pipe on the side of the
.
In any configuration, it will be necessary to add the equivalent length of
the tee (15 feet/5 M) to the Total Equivalent Vent Length of the venting
system.
A12220
Fig. 48 – Sample Inlet Air Pipe Connection for Polypropylene
Venting Systems
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
air inlet pipe, see
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
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.
MAINTAIN 12 IN. (305 MM)
CLEARANCE ABOVE
HIGHEST ANTICIPATED
SNOW LEVEL OR GRADE,
WHICHEVER IS GREATER.
COMBUSTION-AIR
(ELBOW PARALLEL TO WALL)
OVERHANG
12 IN. (305 MM) MIN. GROUND
LEVEL OR ANTICIPATED SNOW LEVEL
EXHAUST
CLEARANCE TO OVERHANG PER CODE
OPTIONAL
BRACKET
COUPLING
12 IN. (305 MM) MIN.
SEPARATION BETWEEN
BOTTOM OF COMBUSTION
AIR AND BOTTOM OF VENT.
NOTICE
!
ADDITIONAL INFORMATION FOR
POLYPROPYLENE VENTING SYSTEMS
Polypropylene venting systems include flexible vent pipe. These
flexible vent pipes have a different equivalent vent length than straight
sections of PVC/ABS DWV vent pipe. Be sure to make the appropriate
deductions from the Maximum Equivalent Vent Length (MEVL), or
additions to the Total Equivalent Vent Length (TEVL), when applying
flexible vent pipes in polypropylene venting systems. See the
polypropylene vent system manufacturer’s installation instructions for
details.
When using metric-sized venting systems, use these equivalencies for
obtaining the proper MEVL from the Tables:
Use 2” Vent Tables for 60 mm (o.d.) vent systems
Use 3” Vent Tables for 80 mm (o.d.) vent systems
Use 4” Vent Tables for 100 mm (o.d.) vent systems
EXAMPLE FOR
UPFLOW INSTALLATIONS.
MAY BE APPLIED TO
OTHER CONFIGURATIONS.