Sheet Metal and HVAC Flashcards
6 cards from real Other Skilled Trades practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Sheet Metal and HVAC flashcards as text
What tool is used to measure the static pressure within an HVAC duct system?
Answer: Manometer or magnehelic gauge
A manometer or magnehelic gauge measures the static pressure (in inches of water column) within ductwork to diagnose airflow restrictions and verify system performance.
What is the purpose of a condensate drain line on a central air conditioning system?
Answer: To remove water condensed from humid air on the evaporator coil
As warm humid air passes over the cold evaporator coil, moisture condenses and drips into a drain pan — the condensate line removes this water from the system.
What gauge (thickness) of sheet metal is most commonly used for residential HVAC trunk ducts?
Answer: 24 gauge
24-gauge galvanized steel is the most common thickness for residential HVAC trunk ducts, providing adequate rigidity while remaining workable for fabrication.
What does the acronym CFM mean in HVAC?
Answer: Cubic Feet per Minute
CFM (Cubic Feet per Minute) is the standard US measurement for airflow volume in HVAC systems, used to specify fan output, register sizing, and duct design.
What is the minimum required clearance around an outdoor condenser unit for proper airflow and service access?
Answer: 18 to 24 inches on all sides
Most manufacturers and codes require 18–24 inches of clearance around outdoor condenser units to ensure adequate airflow for heat rejection and safe service access.
What does a TXV (thermostatic expansion valve) do in a refrigeration system?
Answer: Regulates the flow of refrigerant into the evaporator based on superheat
A TXV meters refrigerant flow into the evaporator coil, automatically adjusting to maintain a set superheat level and ensure the coil is fully utilized without liquid refrigerant reaching the compressor.