Venting - Harman Stove Company Accentra Owner's Manual

Fig.22
+ = Positive static pressure
= Negative static pressure
Fig. 23
Inlet Cover part#
1-10-08543

Venting

Room Sensor
Connection Ports
Outside air flex pipe
goes here
3" PL vent pipe
flue collar
Flex pipe part#
2-00-08543
Fig. 24
Venting
A combustion blower is used to extract the com-
bustion gases from the firebox. This causes a negative
pressure in the firebox and a positive pressure in the
venting system as shown in fig. 22. The longer the vent
pipe and more elbows used in the system, the greater
the flow resistance. Because of these facts we recom-
mend 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 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. Be sure to use a starting collar to attach the
venting systen to the stove. The starting collar must
be sealed to the stove with high temp silicone
caulking.
Vent Pipe
Pellet venting pipe ( also 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 only 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 Accentra operates with a
positive vent pressure, we specify that the joints also
be sealed with clear silicone.
Outside Air
Outside air is optional except in mobile homes and
where building codes require. The benefit of outside air
is mainly noticed in small, very tight houses.
To install outside air use 2 3/8" I.D. flex pipe part
number 2-00-08543. There is a break-away hole on
the rear panel which must be removed before connect-
ing the flex pipe. The pipe should be run outside and
terminate to the side or below the vent pipe outlet so the
flue outlet is more than 12" from the inlet cover. The
maximum length run of this pipe is 15 feet. If a longer run
is needed, the size must be increased to 3". Inlet cover
part number 1-10-08542 should be used to keep birds,
rodents, etc.out of pipe.
HRV
When installing in a house with a Heat Reclaiming
Ventilation System (HRV) be sure the system is balanced
and is not creating a negative pressure in the house.