Goodman GMVM Service Instructions Manual page 28

PRODUCT DESIGN
V /F P T
ENT LUE IPE ERMINATIONS
NOTE: If either a 90 degree or 45 degree elbow is used for
termination, it must be pointed downward.
The vent/flue pipe may terminate vertically, as through a roof, or
horizontally, as through an outside wall.
Vertical vent/flue pipe terminations should be as shown in the
following figure. Refer to Vent/Flue Pipe and Combustion Air
Pipe - Termination Locations for details concerning location re-
strictions. The penetration of the vent through the roof must be
sealed tight with proper flashing such as is used with a plastic
plumbing vent.
Horizontal vent/flue pipe terminations should be as shown in the
following figure. Refer to Vent/Flue Pipe and Combustion Air Pipe
- Termination Locations for details concerning location restric-
tions. A 2 3/8" diameter wall penetration is required for 2" diam-
eter pipe. A 3" diameter hole is required for a 2 1/2" pipe and a 3
1/2" diameter hole is required for 3" diameter pipe. The wall
penetration should be sealed with silicone caulking material.
In a basement installation, the vent/flue pipe can be run between
joist spaces. If the vent pipe must go below a joist and then up
into the last joist space to penetrate the header, two 45° elbows
should be used to reach the header rather than two 90° elbows.
NOTE: Terminate both pipes in the same pressure zone
(same side of roof, no major obstacles between pipes,
etc.).
COMBUSTION AIR INTAKE
(OPTIONAL)
*Not required for
single pipe installation
INTAKE
SCREEN
OPTIONAL
12" MIN TO ROOF OR HIGHEST
ANTICIPATED SNOW LEVEL
STRAIGHT
28
TEE (OPTIONAL)
12" MIN
HEIGHT DIFFERENCE
BETWEEN
INTAKE AND VENT
ELBOWS
12" MIN.
Horizontal Termination (Single Pipe)
Above Highest Anticipated Snow Level
D V (D P ) P
IRECT ENT UAL IPE
The inlet air screens provided in the installation instruction packet
are available for the installer to use in the inlet of the combustion
air pipe to prevent animals from building nests in the combustion
air pipe. Installation of screens, while strongly recommended, is
not required and will not affect performance of the unit.
Direct vent installations require both a combustion air intake and
a vent/flue pipe. The pipes may be run horizontally and exit through
the side of the building or run vertically and exit through the roof of
the building. The pipes may be run through an existing unused
chimney; however, they must extend a minimum of 12 inches
above the top of the chimney. The space between the pipes and
the chimney must be closed with a weather tight, corrosion resis-
tant flashing. Both the combustion air intake and a vent/flue pipe
terminations must be in the same atmospheric pressure zone.
Refer to Vent/Flue and Combustion Air Pipe - Termination Loca-
tions or Concentric Vent Termination for specific details on termi-
nation construction. For details concerning connection of pipes
to the furnace, refer to the Vent/Flue Pipe and Combustion Pipe
- Standard Furnace Connections or Alternate Furnace Connec-
tions.
V /F & C
ENT LUE OMBUSTION
Refer to the following table for applicable length, elbows, and pipe
diameter for construction of the vent/flue and combustion air in-
take pipe systems of a direct vent (dual pipe) installation. The
number of elbows tabulated represents the number of elbows
and/or tees in each (Vent/Flue & Combustion Air Intake) pipe. If
there is a difference between the two pipes, count the pipe
with the most fittings. Elbows and/or tees used in the termina-
tions must be included when determining the number of elbows
in the piping systems.
VENT/FLUE TEE ( OPTIONAL)
or
45° ELBOW
TURNED DOWN or
90° ELBOW TURNED
DOWN
12" MIN. ABOVE
HIGHEST ANTICIPATED
SNOW LEVEL
IPING
A P L &D
IR IPE ENGTHS IAMETERS