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Installation and Operation Manual - HES 240
ENGLISH
If there is no fire burning in a heater connected to a chimney that is shorter than the warm space
inside the house, the slight negative pressure in the lower part of the house will compete against
the desired upward flow in the chimney. This occurs for the two following reasons:
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 in the lower part of the house will draw cold air down
the chimney, through the stove and into the room. Even the finest stove will not work well when
connected to this chimney.
9.5 Supply of Combustion Air
9.5.1 Mobile Home
This stove is ‘mobile home approved’. It must therefore have a supply of combustion air from
outdoors. The air intake must not draw air from the attic, from the basement, from a garage
or any enclosed space. Air must be drawn from a ventilated crawl space under the floor or
directly from outside. Install a flexible or rigid, insulated pipe (HVAC type, must comply to ULC
S110 and/or UL 181, Class 0 or Class 1) to the fresh air intake. 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.
9.5.2 Conventional House
The safest and most reliable supply of combustion air for a wood stove 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 stove. The only case in which the wood stove 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.
Air supply in conventional houses
