Exhaust System Sizing - Buffalo B100 Owner's Installation And Operation Manual

2. Do not install a damper in the exhaust
venting system of this unit.
3. Use of a UL approved wall thimble is
required when passing pipe vent
through any combustible wall.
4. Use only UL listed, 3 or 4 inch PL vent
pipe on all stove installations. A UL
safety listed 3 to 4 inch adapter must
be used when 4-inch vent pipe is
required.
5. Horizontal exhaust system runs of over
15 feet are not recommended.
6. Exhaust systems must maintain a
minimum of ¼" vertical rise for every
12" of horizontal travel.
7. Use of more than 3 tees and/or elbows
in any installation is not suggested.
Exhaust systems with more than 3 tees
and/or elbows may not draft properly.
8. All areas of the exhaust system must
be installed such that all vertical and
horizontal runs can be periodically
inspected and cleaned (plan proper
placement of cleanout tees).
9. A clean out tee must be used at the
bottom of all vertical runs enabling the
collection and removal of fly ash. In
some installations, 4 way tees may be
necessary to enable cleaning access
to both horizontal and vertical exhaust
piping runs.
10. All PL vent pipe manufacturer's
installation and clearance requirements
must be followed.
11. Exhaust system joints may or may not
be required to be attached using sheet
metal screws, please reference the
pellet vent manufacturer's instructions.
If sheet metal screws are required to
attach pellet vent pipe components,
proper length screws must be used to
ensure that the inner liner of the pellet
vent pipe is NOT penetrated.
12. All exhaust system joints located inside
the home must be completely sealed
with high temperature RTV silicone to
guarantee a gas tight seal. Proper
sealing of all exhaust system joints is
required to prevent any leakage of
exhaust fumes into the home.
13. It is strongly recommended that the
exhaust vent system NOT exit and be
terminated on the prevailing wind side
of the home.
14. Exhaust pipe surfaces can get
extremely hot and can cause burns if
touched, care should be taken to
ensure that vent piping is not easily
accessible to people or pets. Shields
or guards, maintaining proper PL vent
clearance may be required for some
installations.
15. Stove may not be placed in, or vented
through a gas fireplace.

Exhaust System Sizing

The exhaust pipe exiting at the rear of your
Buffalo Pellet Stove will accept standard 3"
PL vent pipe. Your Buffalo Pellet Stove is
certified for both 3 and 4 inch exhaust
venting. The numbers of tees, elbows,
horizontal and vertical runs of vent pipe all
add resistance to the flow of air through the
exhaust system. Excessive resistance to the
exhaust air passing through the venting
system can lead to combustion problems in
the stove. A calculation called "total factored
length" is used to determine whether 3 or 4-
inch vent pipe is required. By calculating the
total factored length of your planned exhaust
system, it can be determined if your venting
system will have too much resistance for
standard 3-inch vent pipe to be used.
Adjusting the size of the exhaust system vent
pipe to compensate for these variables will
help improve exhaust gas flow and overall
performance of your stove. The use of 4-inch
vent pipe will reduce this resistance. For
installations requiring a 4-inch PL vent pipe, a
3 to 4-inch PL adapter must be placed on
your stove's exhaust pipe.
Apply the multipliers listed in the table below
to the different components of the exhaust
system, then add up all of the exhaust system
factored components to calculate the total
factored length of the planned exhaust
system. Use this calculated value to
determine the appropriate exhaust system
pipe size (3 or 4").
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