Refrigeration System Quiz

A refrigeration system uses a reciprocating compressor that operates at 1,750 RPM and has a cylinder displacement of 5 cubic inches per stroke. If it has 4 cylinders and completes 2 strokes per revolution, what is the total displacement per minute?

• 35,000 in³/min

• 70,000 in³/min

• 140,000 in³/min

• 280,000 in³/min

A walk-in freezer operates with a suction pressure of 18 psig using R-404A. What is the approximate evaporator temperature?

• -10°F

• -20°F

• -30°F

• -40°F

If a system has a superheat of 5°F and a subcooling of 3°F, what does this indicate?

• The system is undercharged

• The system is overcharged

• The charge is nearly correct

• The TXV is stuck closed

A refrigeration system shows signs of liquid refrigerant returning to the compressor. What could be the cause?

• TXV stuck open

• Low superheat setting

• Oversized metering device

• All of the above

A heat pump operating in heating mode has an outdoor temperature of 35°F and a suction line temperature of 50°F. What is the system’s superheat?

• 5°F

• 10°F

• 15°F

• 20°F

A refrigeration system operates with a head pressure of 260 psig and a liquid line temperature of 100°F using R-134a. What is the approximate subcooling?

• 5°F

• 10°F

A system has excessive discharge temperatures. What are possible causes?

• Low refrigerant charge

• High compression ratio

• Insufficient condenser cooling

• All of the above

A TXV-equipped refrigeration system is overcharged with refrigerant. What symptoms will likely be observed?

• High suction pressure

• High subcooling

• Low discharge pressure

• Low subcooling

What is the temperature from the R-404A P-T chart?

• -10°F

• -20°F

• -30°F

• -40°F

What is the calculated CFM?

• 25 CFM

• 27 CFM

• 29 CFM

• 31 CFM