Stove Builder International VB00003, Installation And Operation Manual

Page: 63 / 92

HE200 - Installation and Operation Manual
63
8.9 Supply of Combustion Air
In Canada, wood fireplaces are not required to have a supply of combustion air from outdoors because
research has shown that these supplies do not give protection against house depressurization and may fail
to supply combustion air during windy weather. However, to protect against the risk of smoke spillage due
to house depressurization,
a carbon monoxide (CO) detector/alarm is required in the room where the
fireplace is installed. The CO detector will provide warning if for any reason the wood fireplace fails to
function correctly.
8.9.1 Air Supply in Conventional Houses
The safest and most reliable supply of combustion air for your wood fireplace is from the room in which it is
installed. Room air is already preheated so it will not chill the fire, and its availability is not affected by wind
pressures on the house. Contrary to commonly expressed concerns, almost all tightly-sealed new houses
have enough natural leakage to provide the small amount of air needed by the fireplace. The only case in
which the wood fireplace may not have adequate access to combustion air is if the operation of a powerful
exhaust device (such as a kitchen range exhaust) causes the pressure in the house to become negative
relative to outdoors.
If you do install an air supply through the wall of the house, be aware that its pressure can be affected
during windy weather. If you notice changes in wood fireplace performance in windy weather, and in
particular if smoke puffs from the fireplace, you should disconnect the outdoor air duct from the fireplace
and remove the duct. In some windy conditions, negative pressure at the duct weatherhood outside the
house wall may draw hot exhaust gases from the fireplace backwards through the duct to outdoors. Check
the outdoor air duct for soot deposits when the full system is cleaned and inspected at least once each
year.