INSTALLATION INSTRUCTIONS
Gas Furnace: (F/G)9MVT, (F/G)9MXT, (F/G)9MXE
38
440 01 4001 05
Specifications subject to change without notice.
Venting Systems
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow the instructions outlined in Locating the
Vent Termination for each appliance being placed into
operation could result in carbon monoxide poisoning or
death.
For all venting configurations for this appliance and other
gas appliances placed into operation for the structure,
provisions for adequate combustion, ventilation, and di-
lution air must be provided in accordance with:
U.S.A. Installations:
Section 9.3 NFPA 54/ANSI
Z223.1 1
−
2012, Air for Combustion and Ventilation and
applicable provisions of the local building codes.
Canadian Installations:
Part 8 of
CAN/CSA
−
B149.1
−
10. Venting Systems and Air
Supply for Appliances and all authorities having
jurisdiction.
NOTICE
RECOMMENDED SUPPORT FOR VENT
TERMINATIONS
It is recommended that sidewall vent terminations of
over 24 inches (0.6 M) in length or rooftop vent termin-
ations of over 36 inches (1 M) in length be supported
by EITHER the factory accessory vent termination kit
or field-supplied brackets or supports attached to the
structure. A factory accessory vent termination kit may
be used for direct vent terminations. Termination kits
are available for 2-in. or 3-in. pipe. See
Table 12
for
available options.
Table 12
Vent Termination Kit for Direct
Vent (2
−
Pipe) Systems
Direct Vent
(2
−
Pipe)
Termination Kit
Termination
System
Diam. Of
Combustion Air
and Vent Pipes
in.(mm)
2
−
in (51 mm)
Concentric Vent
Kit
Single Penetration
of Wall or Roof
1, 1
−
1/2, 2, or 2
−
1/2
(25, 38, 51, 64 mm)
3
−
in (76 mm)
Concentric Vent
Kit
Single Penetration
of Wall or Roof
2
−
1/2, 3 or 4
(64, 76, 102 mm)
2
−
in (51 mm)
Termination
Bracket Kit
2
−
Pipe
Termination
System
1, 1
−
1/2, 2, or 2
−
1/2
(25, 38, 51, 64 mm)
3
−
in (76 mm)
Termination
Bracket
2
−
Pipe
Termination
System
2
−
1/2, 3 or 4
(64, 76, 102 mm)
Direct Vent / 2
−
Pipe System
In a direct
−
vent (2
−
pipe) system, all air for combustion is taken
directly from outdoor atmosphere, and all flue products are
discharged to outdoor atmosphere. Combustion-air and vent
pipes must terminate together in the same atmospheric
pressure zone, either through the roof (preferred) or a sidewall.
See
Figure 60
for references to clearances required by
National code authorities.
NOTICE
OPTIONAL CONFIGURATION FOR COMBUSTION
AIR INLET PIPE
In applications where there is a risk of excessive mois-
ture 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 combus-
tion air inlet pipe. See
Figure 51
.
When sizing venting systems, the equivalent length of
the optional inlet pipe moisture trap must be taken into
account.
Ventilated Combustion Air Systems
In a ventilated combustion air option, the vent terminates and
discharges the flue products directly to the outdoors similar to a
direct vent system. See
Figure 61
for references to clearances
required by National code authorities.
All air for combustion is piped directly to the furnace from a
space that is well ventilated with outdoor air (such as an attic or
crawl space) and the space is well isolated from the living
space or garage. Combustion air requirements for this option
are the same as the requirements for providing outside air for
combustion for a single pipe vent system. Refer to the “Air For
Combustion and Ventilation Section.”
Provisions for adequate combustion, ventilation, and dilution air
must be provided in accordance with:
Non-Direct Vent (1-pipe) System
In a non direct-vent (1-pipe) system, all air for combustion is
taken from the area adjacent to furnace, and all flue products
are discharged to outdoor atmosphere. Air for combustion
must be supplied as described in the Air For Combustion and
Ventilation Section. Do not use an abandoned chimney to
supply outside air to the furnace. See
Figure 61
for references
to clearances required by National code authorities.
A combustion air pipe to the outdoors is not required for a
single pipe vent system. A 12-in. (304 mm) long pipe with a
2
−
in. (50 mm Nominal Dimension
−
ND) tight radius 90 degree
elbow is required to be attached to the combustion air pipe
adapter on the furnace. (See
Figure 57
) This short inlet air pipe
helps to ensure stable combustion, as well as allow for sound
attenuation. To aid sound attenuation, point the inlet air pipe
away from occupants. An extra elbow and/or five feet (1.5 M) of
pipe may be used to accomplish the sound attenuation
function.
NOTICE
OPTIONAL VENTING BELOW THE FURNACE
The venting system may be positioned below the fur-
nace ONLY IF the factory accessory External Vent
Trap Kit is used. The External Vent Trap Kit is only
approved for PVC/ABS DWV venting systems.
CAREFULLY FOLLOW THE INSTRUCTIONS
PROVIDED WITH THE EXTERNAL VENT TRAP KIT
FOR LAYING OUT THE VENTING SYSTEM AND
THE DRAIN SYSTEM.
The instructions included with
this furnace DO NOT APPLY to vent systems that are
located below the furnace
