Harman XXV Pellet Stove Installation & Operating Manual page 9

iMPOrtant nOtice
Approved Pellet Vent Pipe (3" or 4") Must Be
Used unless installing with the optional top 6"
Flue Adapter.
If using 6" Flue Adapter, it is recommended to
use a sealed seam 6" flue pipe (snaplock seam
is not recommended) secure each joint with at
least 3 screws, and seal with high temperature
silicone.In some cases it may be necessary
to use a liner in the existing chimney to obtain
proper draft.
cautiOn
dO nOt cOnnect tO anY air
diStributiOn duct Or SYSteM.
+
= Positive Static Pressure
-
= Negative Static Pressure
Fig. 6
inStall Vent at clearanceS SPeciFied
bY the Vent ManuFacturer.
Venting
Venting
A combustion blower is used to extract the combustion
gases from the firebox. This causes a negative pressure
in the firebox and a positive pressure in the venting
system as shown in Fig. 6. The longer the vent pipe and
more elbows used in the system, the greater the flow
resistance. Because of these facts we recommend using
as few elbows as possible and 15 feet or less of vent
pipe. The maximum horizontal run should not exceed
48". If more than 15 feet of pipe is needed, the interior
diameter should be increased from 3" to 4" because
a larger pipe causes less flow resistance. be sure
to use approved pellet vent pipe wall and ceiling
pass-through fittings to go through combustible
walls and ceilings. The use of a starting collar is not
always necessary. The first piece of pellet vent pipe
must be fastened to the appliance flue collar with at least
3 fasteners. The fasteners provided are a self-drilling
type, however, due to material thickness, drilling a 3/32"
pilot hole for each screw is recommended. Follow vent
manufacturer's instructions for proper connection at
each joint.
Vent Pipe
Pellet venting pipe (Known as "L" or "PL" venting) is
constructed of two layers with air space between the
layers. This air space is an insulator which reduces
the surface temperature and allows a clearance to
combustibles of 3 inches or less. The sections of pipe
lock together to form an air tight seal in most cases.
However, in some cases a perfect seal is not achieved.
For this reason and the fact that the XXV operates with
a positive vent pressure we specify that the joints also
be sealed with silicone.
All joints for connector pipe must be fastened or
secured with a minimum of three screws. We cannot
emphasize enough, the importance of sealing every
seam and joint in the venting system which is inside
the home. Even the smallest pin hole can leak and
when it does you will smell wood smoke or a creosote
smell in the room. If this occurs check for leaks. Leaks
are easiest to see during start-up. Alternatively you
can use a smoke pellet to leak test the venting before
lighting your first fire.
9
XXV Pellet Stove