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provided. Drive the screws through the
slots in the facade frame into the metal
frame of the fireplace. (There are no pre-
drilled pilot holes)
6.
If you are planning to install a non-
combustible facing material behind the
facade, plan the depth of this material
before securing the screws.
7.
The blower door is held closed by a
magnet on the right side of the facade. To
adjust the strength of the closure, spin the
magnet to adjust in/out.
8 THE VENTING SYSTEM
8.1 GENERAL
The venting system, acts as the engine that drives your wood heating system. Even the best fireplace will
not function safely and efficiently as intended if it is not connected to a suitable chimney.
The heat in the flue gases that pass from the fireplace into the chimney is not waste heat. This heat is what
the chimney uses to make the draft that draws in combustion air, keeps smoke inside the fireplace and
safely vents exhaust to outside. You can think of heat in the flue gas as the fuel the chimney uses to make
draft.
8.2 SUITABLE CHIMNEYS
Your wood fireplace will provide optimum efficiency and performance when connected to an 8-inch
diameter chimney.
8.3
MINIMUM CHIMNEY HEIGHT
The top of the chimney should be tall
enough to be above the air turbulence
caused when wind blows against the
house and its roof. The chimney must
extend at least 1 m (3 ft.) above the
highest point of contact with the roof, and
at least 60 cm (2 ft.) higher than any roof
line or obstacle within a horizontal
distance of 3 m (10 ft.).
8.4 THE RELATIONSHIP BETWEEN THE CHIMNEY AND THE HOUSE
Because the venting system is the engine that drives the wood heating system, it must have the right
characteristics. The signs of bad system design are cold backdrafting when there is no fire in the fireplace,
slow kindling of new fires, and smoke roll-out when the door is opened for loading.
8.4.1 WHY THE CHIMNEY SHOULD PENETRATE THE HIGHEST HEATED SPACE
When it is cold outside, the warm air in the house is buoyant so it tends to rise. This tendency of warm
air to rise creates a slight pressure difference in the house. Called 'stack effect', it produces a slightly
negative pressure low in the house (relative to outside) and a slightly positive pressure zone high in
the house. If there is no fire burning in a heater connected to a chimney that is shorter than the warm
HearthStone Quality Home Heating Products, Inc ®
39
WFP-100 Model 8420
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