Harman PELLET P61A Installation & Operating Manual page 8

iMPORtAnt nOtice
Approved Pellet Vent Pipe- Widely Known As
"PL Vent", Must be used.
-
+
= Positive Static Pressure
-
= Negative Static Pressure
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. 7. 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 pipe must be secured, with
at least 2 fasteners, to the flue collar of the stove. The
2 screws provided are self-drilling, however, drilling a
3/32" pilot hole for each screw is recommended due to
the material thickness.
venting
vent Pipe
Pellet venting pipe (known as PL vent) is constructed
of two layers with air space between the layers.
This air space acts as an insulator and reduces the
outside surface temperature to allow a clearance to
combustibles of 1 to 3 inches. 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 P61A operates with
a positive vent pressure we specify that the joints also
be sealed with silicone. Aluminum tape can also be
used for any joint that is 1 ft. or more from the outlet
of the stove.
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.
A chiMneY MuSt be OF A tYPe SuitAble
FOR SOlid Fuel.
+
chiMneY And cOnnectOR MuSt be
MAintAined in gOOd cOnditiOn And kePt
Fig. 7
cleAn.
Avoiding Smoke and Odors
negative Pressure, Shut-down, and Power
Failure:
To reduce the probability of back-drafting or
burn-back in the pellet burning appliance during
power failure or shut-down conditions, the stove
must be able to draft naturally without exhaust blower
operation. Negative pressure in the house will resist this
natural draft if not accounted for in the pellet appliance
installation.
Heat rises in the house and leaks out at upper levels.
This air must be replaced with cold air from outdoors,
which flows into lower levels of the house. Vents and
chimneys into basements and lower levels of the house
can become the conduit for air supply, and reverse
under these conditions.
Outside Air:
harman home heating and hearth & home
technologies strongly recommend attaching
outside air in all installations, especially lower level
and main floor locations.
8
P61A Pellet Stove