NATE Exam: AC & HP (A+ Graded answers)

a (Centrifugal) correct answers Which of the following compressors are considered a dynamic compressor? a. Centrifugal b. Reciprocating d. Rotary c. Scroll b (Superheated vapor / sub cooled liquid) correct answers What is the condition of the refrigerant as it enters and leaves the condensing coil of a typical light commercial HVAC system? a. Vapor / liquid b. Superheated vapor / sub cooled liquid c. Saturated vapor / saturated liquid d. Hot gas / cool liquid b (Thermal expansion valve) correct answers Which one of the following are considered the best metering device of the industry? a. Capillary tube b. Thermal expansion valve d. Constant pressure expansion valve c. Electronic expansion valve b (POE. Newer refrigerant systems today using R-134a and R-410a use a synthetic Polyester POE oil. Older refrigeration systems using R-12, R-502, and R-22 use a mineral based oil.) correct answers Which of the following types of refrigeration oil would you expect to find in a typical commercial R-134a freezer?