Page 38
Installation and Operation Manual - Osburn 3500
Use 45 degrees elbows where possible, instead of 90 degrees elbows.
The rules below are based on those found in the AS/NZS 2918:2001 installation code. Please
carefully follow these installation instruction rules, or those enforced where you live.
• Maximum overall length of the straight flue system: not less than 4.6 m above the top of the floor
protector.
• The flue should be as short and direct as possible between the wood fire and flue system. The use
of two 45 degree elbows is often preferable to a single 90 degree elbow because less turbulence is
created in the exhaust flow and they result in less horizontal run.
• Flue must be at least 24 gauge in thickness.
• Flue joints should overlap 30 mm.
• Each joint in the flue must be fastened with at least three screws.
• The flue must have allowance for expansion: elbows in assemblies allow for expansion; straight
assemblies should include an inspection wrap with one end unfastened, or a telescopic section.
• There must be provision for cleaning of the flue, either through a clean out or by removal of the flue.
Removal of the flue should not require that the wood fire be moved.
• The male ends of the sections must be oriented towards the appliance so that falling dust and
condensation stay inside the wood fire.
• A flue must never pass through a combustible floor or ceiling or through an attic, roof space, closet
or concealed space.
• Where passage through a wall or partition of combustible construction is desired, the installation
shall conform to AS/NZS 2918:2001.
The ideal flue is one that rises straight up from the appliance flue collar and directly into the flue
system with no elbows. A straight up flue needs either a telescopic length or an inspection wrap (flue
coupler) to allow it to be assembled and disassembled without moving the wood fire.
A straight flue offers the least restriction to gas flow and results in a stronger draft. Straight assemblies
also need less maintenance because there are no corners to collect creosote.
The flue must be in good condition.
To Next Page
