440 01 4201 03
41
Specifications subject to change without notice.
The measured length of pipe used in a 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 (see vent
termination figures associated with
) do not require a
deduction from the Maximum Equivalent Vent Length. 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.
3. For each pipe, multiply the number of elbows by the
equivalent length for the type of elbow used. Record the
equivalent length of all the elbows for each pipe.
4. If a Tee is used on the termination (Alberta and
Saskatchewan, when required), record the equivalent
length of the Tee used.
5. Calculate Total Equivalent Vent Length by adding the
equivalent lengths of the fittings to the lengths of the
individual vent and combustion air pipes.
6. When using polypropylene venting systems with flexible
vent pipes, perform adjustments for the equivalent length
of the flexible vent pipe to the calculated total equivalent
venting system length. See the polypropylene vent
system manufacturer’s instructions for details.
7. Select a diameter of vent pipe from
and
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
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
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
total allowable pipe length as calculated from
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
)
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
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