Osburn OB04002 - Manual (Page 67)

Stratford Fireplace Installation and Operation Manual
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8.10.1 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.