Operating instructions

Heatmax Furnace Installation and Operation Manual

8.3 Minimum chimney height

The top of the chimney should be

tall enough to be above the air

turbulence caused when wind

blows against the house and its

roof. The chimney must extend at

least 1 m (3 ft.) above the highest

point of contact with the roof, and

at least 60 cm (2 ft.) higher than

any roof line or obstacle within a

horizontal distance of 3 m (10 ft.).

8.4 Relationship between the chimney and the house

Because the venting system is the engine that drives the wood heating system, it must

have the right characteristics. The signs of bad system design are cold back drafting when

there is no fire in the furnace, slow kindling of new fires, and smoke roll-out when the door

is opened for loading. There are two guidelines to follow. First, the chimney should be

installed up through the heated space of the house, not out and up an outside wall.

Second, the chimney should penetrate the top of the building at or near the highest heated

space.

8.4.1 Why inside chimneys are preferred

Venting systems that rise straight up from the furnace flue collar provide the best

performance. Chimneys that rise inside the warm space of the house tend to provide a

small amount of draft even when there is no fire burning. This means that when you light a

fire, the initial smoke goes up the chimney and strong draft builds quickly as the chimney

flue warms up. Although they are common in North America, chimneys that exit a house

wall and run up outside can cause problems.