Commercial Refrigeration Systems Flashcards
7 cards from real CFC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Commercial Refrigeration Systems flashcards as text
A commercial refrigeration technician is replacing a hermetic compressor. After the repair, the system must be evacuated to at least:
Answer: 500 microns
EPA and industry standards require deep evacuation to 500 microns or lower to ensure all moisture and non-condensable gases are removed before recharging.
Which factor most determines the condensing temperature in an air-cooled commercial refrigeration system?
Answer: Ambient air temperature at the condenser
In air-cooled systems, the ambient temperature at the condenser sets the lower limit for condensing temperature, as heat must flow from refrigerant to the surrounding air.
A technician wants to add refrigerant to a commercial system that uses R-404A. How must this blend be charged?
Answer: As liquid only, since it is a near-azeotropic blend
R-404A is a near-azeotropic zeotropic blend; charging as liquid ensures the correct mixture ratio is maintained, since vapor charging can cause fractionation.
In a large commercial refrigeration system, a desuperheater is used primarily to:
Answer: Remove superheat from discharge gas to recover heat for water heating
A desuperheater extracts heat from hot discharge gas to heat water, recovering waste heat and improving overall system efficiency.
What is the purpose of a crankcase pressure regulator (CPR) valve in a commercial refrigeration system?
Answer: Limit suction pressure to the compressor during high-load pulldown
A CPR valve limits the suction pressure entering the compressor during high-load pulldown conditions to prevent motor overload and compressor damage.
Which refrigerant safety classification indicates both low toxicity and low flammability, making it commonly used in commercial refrigeration?
Answer: A1
ASHRAE safety class A1 denotes low chronic toxicity (A) and no flame propagation (1), making it the safest class and common in commercial refrigeration applications.
A commercial refrigeration system using R-22 needs to be retrofitted. The technician should first:
Answer: Recover all R-22, flush the system, change the oil, then charge with the new refrigerant
A proper R-22 retrofit requires full recovery, system flushing if needed, oil change to compatible POE or AB oil, and then charging with the approved replacement refrigerant.