Osburn OB01520 - Manual (Page 42)

Soho Installation and Operation Manual
42 ________________________________
Good System Design
Inside chimneys are preferred because even when
no fire is burning, there is normally upward flow in
the system.
8.4.2 WHY THE CHIMNEY SHOU
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’, i
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 space inside the house, the
compete against the desired upward flow in the chimney.
Installation and Operation Manual
________________________________________________________________
Good System Design
neys are preferred because even when
no fire is burning, there is normally upward flow in
Inferior System Design
Outside chimneys are a problem because
when no fire burns they will go into cold
backdraft if the stove is installed low in the
house.
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’, i
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 space inside the house, the slight negative pressure low in the house will
compete against the desired upward flow in the chimney.
______________________________________________
Inferior System Design
Outside chimneys are a problem because
when no fire burns they will go into cold
backdraft if the stove is installed low in the
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
slight negative pressure low in the house will