Osburn OB01520 - Manual (Page 43)

Soho Installation and Operation Manual
______________________________________________________________________________ 43
There are two reasons why the
chimney in the house at right will
cold backdraft when it is cold outside
and there is no fire burning in the
stove. First, the chimney runs up the
outside of the house, so the air in it
is colder and denser than the warm
air in the house. And second, the
chimney is shorter than the heated
space of the house, meaning the
negative pressure low in the house
will pull outside air down the
chimney, through the stove and into
the room. Even the finest stove will
not work well when connected to
this chimney.
8.5 SUPPLY OF COMBUSTION AIR
In Canada, wood stoves are not required to have a supply of combustion air from outdoors (except
in mobile homes) 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 in which the stove is installed. The CO detector will
provide warning if for any reason the wood stove fails to function correctly.
8.5.1 COMBUSTION AIR SUPPLY IN MOBILE HOMES
Only a wood stove certified and labelled as ‘mobile home approved’ may be installed in a mobile
home. The Soho stove is ‘mobile home approved’. Wood stoves installed in mobile homes must
have a ducted supply of combustion air from outdoors. This air supply should be routed down
through the house floor into the vented crawl space under the mobile home. The air supply duct
should be non-combustible aluminum flex duct with a screened weatherhood on the outside end.
Note: Fabric duct may also be used, provided it is suitable for HVAC use and meets the
requirements of ULC-S110 or UL-181 Class 1 standards. It must have a non-combustible insulation
and be corrosion resistant.
Where a mobile home has been converted to a standard house by mounting it on a permanent
basement foundation, the supply of outdoor air is not required.