Question: A flow control device that stops or allows the flow of a refrigerant in a refrigeration system based on an electric signal in:

Answer: A solenoid valve.

Question: A refrigeration component whose purpose is to prevent liquid refrigerant from returning to the compressor is:

Answer: A suction-line accumulator.

Question: A suction-to-liquid line heat exchanger:

Answer: Increases both superheat and subcooling.

Question: Along with the refrigerant that is being discharged, compressors will discharge which of the following as it leaves the compressor?

Answer: Oil

Question: How can a technician determine when a filter drier is stopped up and needs changing?

Answer: The pressure drop will exceed 2 psig.

Question: In most commercial refrigeration systems, most of the excess refrigerant that is not being used is stored in:

Answer: The liquid receiver.

Question: Moisture indicators are normally part of:

Answer: A sightglass.

Question: One method of elevating system liquid pressure is to:

Answer: Control the operation of the condenser fan motors.

Question: The advantage of ball valves over other types of manual refrigeration valves is that they:

Answer: Offer less resistance to flow.

Question: Using heat-reclaim coils will help improve a building's overall:

Answer: Heat efficiency.

Question: What are the most common desiccant materials used in driers?

Answer: Molecular sieve and activated alumina

Question: What are the two basic types of relief valves used on refrigeration systems?

Answer: An automatic relief valve and a one-time relief valve

Question: What does a crankcase pressure regulator do?

Answer: It will not allow the compressor suction pressure to rise above the CPR setpoint.

Question: What does an evaporator pressure regulator do?

Answer: It will not allow the evaporator pressure to drop below its setpoint, even if the suction pressure is lower.

Question: What is the advantage of using a pressure relief valve to protect a receiver instead of a fusible plug?

Answer: The pressure relief valve resets itself.

Question: What is the material inside the filter drier called?

Answer: Desiccant

Question: What type of systems normally use crankcase pressure regulators?

Answer: Low-temperature refrigeration applications such as walk-in and reach-in freezers

Question: What types of systems use evaporator pressure regulators (EPR)?

Answer: Systems with multiple evaporators

Question: When installing a solenoid valve:

Answer: The arrow stamped on the body should point in the direction of flow.

Question: Where in the system is an oil separator installed?

Answer: In the discharge line leaving the compressor

Question: Which of the following are used to separate and collect some of the oil in the discharge line as it leaves the compressor and then return it to the compressor's crankcase?

Answer: Oil separators

Question: Which of the following conditions is NOT considered when selecting a CPR valve?

Answer: Humidification capacity of the system

Question: Which of the following types of valve is NOT considered an isolation valve?

Answer: Solenoid valve

Question: Which refrigeration device would most likely be installed in the discharge line leaving the compressor to prevent liquid refrigerant from draining from a raised condenser into the compressor head?

Answer: A check valve

Question: Why are liquid-line filter driers required for all systems using HFC refrigerant?

Answer: Because the POE oil used with HFC refrigerant is very hygroscopic.

Question: Why is it necessary to have controls for maintaining a minimum high-side pressure on outdoor air-cooled condensers?

Answer: Refrigeration metering devices require a minimum pressure drop to operate.

Question: Why is the filter drier important?

Answer: It keeps the system clean and dry