Application Considerations
Figure A-6 - A Comparision of Drain
Pan Designs
Figure A-7 - Proper Trapping - Drain
Location Examples and Trapping Height Requirements
Water Management. Cooling coils collect water from the passing air stream as they cool and dehumidify it. If not
properly addressed, this condensed moisture encourages
mold, mildew and other microorganisms to colonize and breed. To reduce the likelihood
of microbial growth, apply these guidelines when
designing the air handler:
Reduce moisture carryover by sizing the cooling coils for proper airflow velocities (e.g., typically 350-600 fpm, depending
on air conditions and coil fin arrangement).
Specify drain pans sloped in two directions to eliminate moisture- collecting
level seams and promote positive drainage; see Figure
A-6.
Properly size condensate traps as shown in Figure A-7 to ensure proper drainage.
Promote cleanability — i.e., provide
adequate space around the unit, easily removable access panels, and a solid steel liner to isolate insulation from the air
stream and facilitate cleaning.
Specify antimicrobial coatings for filter
and drain pan surfaces where moisture is likely to collect. (Though cooling coil surfaces collect water, too, treatment with an
antimicrobial coating is discouraged; such coatings
greatly reduce the coil’s wetting characteristics
and may cause moisture carryover at velocities as low as 200 fpm.)
Condition mechanical equipment room to minimize condensation on piping, ductwork, mechanical equipment, etc.
|
