The simplest type of air system is a single zoned constant volume air handling unit satisfying only one zone sensor. These units are designed to condition the space temperature and humidity closely and efficiently and can be shut down when desired temperature has been reached to conserve energy. This type of unit can be either refrigerant cooled or by chilled water. A unit like this would be installed on a rooftop, floor mounted, or above the ceiling. These units would most likely be serving areas were the heat loads are even throughout, and in open areas such as classrooms, department stores, and computer rooms. They can also be effective in larger office buildings were multiple smaller units are used. Here is a list of things that should be considered before balancing a constant volume unit.
- Filters must be clean!
- Check fan rotation, belt tention, and motor amp draw.
- The grille design and unit airflow design should be the same.
- Look for closed dampers in the return and supply duct.
- Verify that all ductwork has been sealed.
- If unit has outside air set the damper to an estimated position. Recheck fresh air amount after unit airflow has been balanced.
- Condensate drain must be installed with vent in the correct location.
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