INSTALLATION INSTRUCTIONS
Gas Furnace: (F/G)9MAE
42
440 01 4300 02
Specifications subject to change without notice.
7. Select a diameter of vent pipe from
Table 14
and
Table 16
and note the Maximum Equivalent Vent Length
(MEVL) shown for that application for that specific
furnace input size. Compare the Total Equivalent Vent
Length (TEVL) to the MEVL:
a. If the Total Equivalent Vent Length is
shorter
than the
Maximum Equivalent Vent Length for the diameter of
pipe chosen, then that diameter of pipe selected may
be used.
b. If the Total Vent Length is
longer
than the Maximum
Equivalent Vent Length for the diameter of pipe
chosen, that diameter pipe MAY NOT be used for
venting the furnace. Try the next larger diameter pipe.
NOTE
: If the calculated Total Equivalent Vent Lengths results
in different diameter pipes for the vent and combustion air,
select the larger diameter for both pipes.
NOTE
: If the Maximum Vent Length for diameter of the pipe
selected is longer than the measured length and the equivalent
length of all the fittings and terminations (TEVL), recalculate
Total Equivalent Vent Length using the next smaller diameter. If
the Maximum Vent Length is still longer than the longer TEVL
of the vent pipe or combustion air pipe, then that diameter of
pipe selected may be used.
When installing vent systems with pipe lengths of 10 ft. (3.0 M)
or less, use the smallest allowable pipe diameter. Using pipe
size greater than required for short venting systems may result
in loss of efficiency, incomplete combustion, flame disturbance,
or flame sense lockout.
For vent systems longer than 10 ft. (3.0 M), any larger diameter
shown in
Table 14
and
Table 16
for that size model may be
used.
Combustion Air and Vent Piping Insulation
Guidelines
NOTE
: Use closed cell, neoprene insulation or equivalent.
The vent pipe may pass through unconditioned areas. The
amount of exposed pipe allowed is shown in
Table 17.
1. Using winter design temperature (used in load
calculations), find appropriate temperature for your
application and furnace model.
2. Determine the amount of total and exposed vent pipe.
3. Determine required insulation thickness for exposed pipe
length(s).
4. When combustion air inlet piping is installed above a
suspended ceiling, the pipe
MUST
be insulated with
moisture resistant insulation such as Armaflex or other
equivalent type of insulation.
5. Insulate combustion air inlet piping when run in warm,
humid spaces.
6. Install the insulation per the insulation manufacturer’s
installation instructions.
NOTE
: Pipe length (ft / M) specified for maximum pipe lengths
located in unconditioned spaces (See
Table 17
) cannot exceed
total allowable pipe length as calculated from
Table 14
or
Table 16
.
Configure the Furnace
!
WARNING
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal
injury or death.
To route the vent pipe and combustion air pipe through
the furnace, the manufacturer supplied kit must be
used. Failure to properly seal the blower compartment
from the furnace vestibule could result in the
circulation of carbon monoxide throughout the
structure. The vent pipe and combustion air pipe must
be a continuous pipe while passing through the blower
compartment. Seals supplied in this kit must be
installed per the instructions provided. Follow all
procedures outlined in these instructions.
Install the Vent and Combustion Air Pipes
With the furnace installed in the required position, remove the
desired knockouts from the casing. It will be necessary to
remove one knockout for the vent pipe and the other knockout
for the combustion air connection. (See
Figure 12
)
Use a flat blade screwdriver and tap on the knockout on
opposite sides, where the knockout meets the casing. Fold the
knockout down with duct pliers and work the knockout back
and forth until it is removed. Trim any excess metal from the
knockout with tin snips.
The vent elbow can be rotated to the required location on the
casing if necessary. See
Figure 50
To rotate the vent elbow:
1. Loosen the clamp on the inlet of the vent elbow attached
to the inducer.
2. Rotate the vent elbow to the required position. There are
rounded notches in the vent elbow to align it with the
inducer for each orientation.
3. Tighten the clamp around the vent elbow. Torque the
clamp to 15 lb-in. See
Figure 51
through
Figure 54
.
Figure 50
Inducer Vent Elbow
−
Variable
MODULATING INDUCER ASSEMBLY
VENT ELBOW CL AMP
TORQUE 15 LB
−
IN.
VENT PIPE
CL AMP
TORQUE 15
LB
−
IN.
INDUCER
OUTLET
VENT
ELBOW
