PG92MSA: 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.
38
A13078A
Fig. 49 – Alberta and Saskatchewan Vent Termination
A93034
Fig. 50 – Combustion Air and Vent Pipe Diameter Transition 
Location and Elbow Configuration
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 Fig. 51. 
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
pipe  above  the  drain. See Fig. 12. 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
casing. See Fig. 51. 
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.
The  measured  length  of  pipe used in a single or  2-pipe  termination  is
included in the total vent length. Include deductions from the Maximum
Equivalent  Vent  Length  (MEVL)  contained  in  the  Venting  Tables  for
elbows  and  flexible  vent  pipe.  Factory  accessory  concentric  vent
terminations  or  pipe  lengths  and  elbows  used  for  “standard”  vent
terminations do not require a deduction from the Maximum Equivalent
Vent  Length.  See  vent  termination  figures  associated  with  Table 14.
Include a deduction for a Tee when used for Alberta and Saskatchewan
terminations.
NOTE:  Polypropylene  venting  systems  MAY  require  additional
deductions  from  the  MEVL,  or  additions  to  the  TEVL,  for  vent
terminations and flexible  pipe  sections. See the polypropylene venting
system  manufacturer’s  instructions for  details  on equivalent lengths of
vent terminations and flexible vent pipes, and for calculating total vent
lengths.
To  calculate  the  Total  Equivalent Vent  Length  (TEVL)  of  the  venting
system:
1. Measure the individual distance from the furnace to the termination
for each pipe.
2. Count the number of elbows for each pipe. 
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 Fig. 51.
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
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