Refrigeration Systems and Heat Transfer Flashcards
7 cards from real ASF practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Refrigeration Systems and Heat Transfer flashcards as text
A refrigerator is not maintaining proper temperature. Which area should a technician inspect FIRST before considering component replacement?
Answer: Check if the condenser coils are dirty or airflow is restricted
Dirty or blocked condenser coils are among the most common causes of inadequate cooling since they reduce heat rejection ability; checking this requires no parts and should come first.
A refrigeration system shows high suction pressure and low discharge pressure. What does this most likely indicate?
Answer: The compressor has failing or worn internal valves
High suction pressure combined with low discharge pressure indicates the compressor is not building adequate pressure differential, typically caused by worn or failed compressor valves.
What instrument does a refrigeration technician use to simultaneously read both high-side and low-side system pressures?
Answer: Manifold gauge set
A manifold gauge set connects to both the high and low side service ports simultaneously, allowing the technician to read system pressures and diagnose refrigeration problems.
What is the recommended method for locating refrigerant leaks in a sealed refrigeration system?
Answer: Use an electronic leak detector or apply a soapy water solution to suspect areas
An electronic leak detector or soapy water solution are the recommended methods, as most modern refrigerants are odorless or nearly so and cannot be reliably detected by smell.
A technician observes that the evaporator in a refrigerator is completely encased in ice. What is the MOST likely cause?
Answer: The defrost system has failed and is not melting accumulated frost
A completely iced-over evaporator is the classic symptom of a failed defrost system, which normally melts frost periodically to maintain efficient heat transfer.
Before opening a refrigeration system for service, what is the MOST critical regulatory requirement regarding refrigerant?
Answer: Recover the refrigerant using EPA-certified equipment before opening the system
EPA Section 608 regulations legally require that refrigerant be recovered using approved equipment before opening a system, as intentional venting is illegal and environmentally harmful.
What is the purpose of an accumulator located on the suction line of a refrigeration system?
Answer: To store excess refrigerant and prevent liquid slugging into the compressor
An accumulator catches any liquid refrigerant on the suction line and allows only vapor to enter the compressor, preventing liquid slugging which can cause serious compressor damage.