Air Systems Cleaning Specialist (ASCS) Practice Exam

Calcium carbonate is commonly found in HVAC units, particularly in areas where moisture is present, such as cooling coils or drain pans. It often accumulates from hard water deposits, which can lead to scaling. This scaling can reduce the efficiency of the system by restricting airflow and heat exchange, potentially increasing energy costs and leading to system malfunctions. While skin flakes may be present in the system due to human presence, they are not a primary contaminant that significantly affects HVAC performance. Similarly, pieces of filter media might occur but are typically a result of improper maintenance or installation rather than a common contaminant. Arsenic derivatives are not a typical concern in HVAC units and would generally be considered hazardous materials rather than common contaminants found in them.