Filter
Top Products
113376-4 Telephone 01422 822282 11
!
Note
When the exhaust ductwork passes through a wall, ceiling, or roof
made of combustible materials, the opening must be 2-inches (5.08
cm) larger than the duct (all the way around). The duct must be centered
within this duct.
Outside Ductwork Protection
To protect the outside end of the horizontal ductwork from the weather, a 90°
elbow bent downward should be installed where the exhaust exits the building.
If the exhaust ductwork travels vertically up through the roof, it should be
protected from the weather by using a 180° 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, louvers, or caps on the outside opening of the
exhaust ductwork.
!
Important
The dryer is not provided with a
back draft damper. When
exhausted into a multiple (common)
exhaust line, a back draft damper must
be installed at each dryer duct.
No more than 3 dryers should be
connected to 1 main common duct.
The main duct may be any shape or
cross-sectional area, as long as the
minimum cross section area is provided.
The illustrations show the minimum cross
section area for multiple dryer round or
square venting. These figures must be
increased 10 square inches (64.52 square
centimeters) when rectangular main
ducting is used, and the ratio of duct width
to depth should not be greater than 3-1/2
to 1. These figures must be increased in
proportion if the main duct run to the last
dryer to where it exhausts to the outdoors
is unusually long (over 20 feet [6.09
meters]) or has numerous elbows (more
than 2) in it. In calculating ductwork size,
the cross-sectional area of a square or
rectangular duct must be increased 20%
for each additional 20 feet (6.09 meters).
The diameter of a round exhaust must be
increased 10% for each additional 20 feet
(6.09 meters). Each 90° elbow is
equivalent to an additional 40 feet (12.19
meters) and each 45° elbow is equivalent
to an additional 20 feet (6.09 meters).
Important
For extended ductwork runs,
the cross section area of the
ductwork can only be increased to an
extent. Maximum proportional ductwork
runs cannot exceed 20 feet (6.09
meters) more than the original limitations
of 20 feet (6.09 meters) with 2 elbows.
When the ductwork approaches the
maximum limits as noted in this manual,
a professional HVAC firm should be
consulted for proper venting information.
Exhaust back pressure measured by a
manometer in the exhaust duct must be
no less than 0 and must not exceed 0.3
in WC (0.74 mb).
The ductwork 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 ductwork 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 ductwork for periodic
inspection and cleaning of lint from the
ductwork.
!
!