American Dryer Corp. AD-75 - Manual (Page 17)

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D. FRESH AIR SUPPLY
When the dryer is operating, it draws in room air, heats it, passes this air through the basket (tumbler), and
exhausts it out of the building. Therefore, the room air must be continually replenished from the
outdoors. If the make-up air is inadequate, drying time and drying efficiency will be adversely affected.
Ignition problems and sail switch "fluttering" problems may result, as well as premature motor failure
from overheating.
Air supply (make-up air) must be given careful consideration to assure proper performance of each dryer.
An unrestricted source of air is necessary for each dryer. An air flow of 1,200 cfm (cubic feet per minute)
must be supplied to each gas and electric dryer and 1,350 cfm (cubic feet per minute) must be supplied to
each steam dryer. As a general rule, an unrestricted air entrance from the outdoors (atmosphere) of a
minimum of 1-1/2 square feet is required for each dryer.
To compensate for the use of registers or louvers used over the openings, this make-up air must be
increased by approximately thirty-three percent (33%). Make-up air openings should not be located in an
area directly near where exhaust vents exit the building.
It is not necessary to have a separate make-up air opening for each dryer. Common make-up air openings
are acceptable. However, they must be set up in such a manner that the make-up air is distributed equally
to ALL the dryers.
EXAMPLE: For a bank of four (4) dryers, two (2) unrestricted openings measuring 2 feet by
1-1/2 feet (6 square feet) is acceptable.
Allowances must be made for remote or constricting passageways or where dryers are located at exces-
sive altitudes or predominantly low pressure areas.
IMPORTANT : Make-up air must be provided from a source free of dry cleaning solvent
fumes. Make-up air that is contaminated by dry cleaning solvent fumes
will result in irreparable damage to motors and other dryer components.
NOTE : Component failure due to dry cleaning solvent fumes will VOID THE WARRANTY.