Application Considerations - Carrier PREMIER 52P SERIES Architects And Engineers' Manual

APPLICATIONS (cont)
APPLICATION
CONSIDERATIONS
Installation instructions are shipped with all PTAC
units. It is important that air conditioning systems be
properly sized and installed for each application in
order to achieve the desired temperature and humidity
levels within the space to be conditioned. It is strongly
recommended that a professional engineer match the
PTAC units with the building structure and climate.
The following application considerations are all
important in choosing the proper PTAC system for the
building structure.
Undersizing
If a PTAC unit is undersized (cooling capacity is less
than required capacity for an application), the unit will
not be able to cool the space down to the desired tem-
perature during very hot days. The result could be
warm and humid or warm and dry conditioned space.
Oversizing
If a PTAC unit is oversized (cooling capacity is greater
than required capacity for the specific application), the
unit will cool the space down to the desired tempera-
ture too quickly.
The unit will cycle on and off, however, dehumidifica-
tion only takes place when the unit is operating. The
result of this type of application in a hot and/or humid
climate would be a cool, yet excessively humid, space.
Air Infiltration
Excessive air infiltration can intensify problems asso-
ciated with undersizing or oversizing a PTAC unit.
This can be the cause of insufficient cooling, dehumid-
ification, or heating. Sources of air infiltration include
vents, gaps around windows and doors, and improp-
erly sealed floors, ceilings or wall joints.
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