Rev 6.1 November 1, 2016
9
Ductwork
An engineer or other qualified person should design the duct system.
•
Duct runs should be straight with minimum bends and elbows.
•
Ensure joints are tight-fitting and sealed with duct tape or sealer.
•
Use galvanized duct whenever possible. Although flexible duct can be used, its use
should be restricted to areas indicated (to outside hoods and in unheated spaces).
•
Flexible ducting may be desired in some installations for noise abatement.
To ensure
effective air flow, use only as much flexible ducting as necessary and keep it taut.
•
All ducting must be supported every 3’ or less.
•
Be sure to seal all pipe joints with foil tape or a duct sealant.
•
When possible, form elbow joints so that they are as straight as possible.
5
th
Port Recirculation and Defrost Strategies (ducting)
For units equipped with a 5
th
port, there are three options to suit the requirements of the installation:
1. Unducted. Simply allow the unit to draw ambient air from the space in which
the unit is located.
2. Ducted with a grill. Duct the 5
th
port to a neutral space. This approach is
particularly useful in distributing super-heated air in which there might be a
wood stove or fireplace. This approach is also useful if the room where the unit
is installed is used to store undesirable or perhaps noxious chemicals.
3. Connected to the Exhaust from Building Pipe. While this method involves
recirculation of exhaust air from the building, it does avoid the potential of
circulating unwanted chemical gases if the mechanical room is used to store such
substances were the 5
th
port left open. It also removes any risk of depressurization in
mechanical rooms that might contain combustion equipment. The Novoclimat
