17
IMPORTANT
: For extended duct work runs, the cross section area of the duct work can only be
increased to an extent. Maximum proportional duct work runs
cannot
exceed fifteen
(15) feet with two (2) elbows. When the duct work approaches the maximum limits
as noted in this manual, a professional HVAC firm
should be
consulted for proper
venting. HVAC
should be
consulted for proper venting information.
IMPORTANT
:
Exhaust back pressure measured by a manometer at each dryer exhaust duct area
should
not
exceed .3 inches of water column (W.C.).
The duct work
should be
smooth inside with no projections from sheet metal screws or other obstructions
which will collect lint. When adding ducts, the duct to be added should overlap the duct to which it is to be
connected.
ALL
duct work joints
must be
taped to prevent moisture and lint from escaping into the
building. Inspection doors
should be
installed at strategic points in the exhaust duct work for periodic
inspection and clean-out of lint from the duct work.
NOTE
: Where the exhaust passes through a wall, ceiling, or roof made of combustible materials, the
opening
must be
2-inches larger (all the way around) than the duct. The duct
must be
centered within this opening.
a. Outside Duct Work Protection
1) To protect the outside end of horizontal duct work from whether, a 90º elbow bent downward
should be
installed where the exhaust exits the building. If the duct work travels vertically up through the roof, it
should be
protected from the whether by using a 180º turn to point the opening downward. In either case,
allow at least twice the diameter of the duct between the duct opening and the nearest obstruction.
IMPORTANT:
DO NOT
use screens or caps on the outside of opening of exhaust duct work.
