ADC ML-145 Installation And Operator's Manual page 22

IMPORTANT: For extended duct work runs, the cross section area of the duct can only be increased
to an extent. Maximum proportional duct work runs cannot exceed twenty (20) feet
more than the original limitations of twenty (20) feet with two (2) elbows. When the
duct work approaches the maximum limits as noted in this manual, a professional
heating venting air conditioning (HVAC) firm should be consulted for proper venting
information.
ALL 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 duct 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 the weather, a 90
DO NOT
must be
should be
18