One method of elevating system liquid pressure is to:Control the operation of the condenser fan motors.

Control the operation of the condenser fan motors. A suction-line accumulator.

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? Oil separators

Which of the following conditions is NOT considered when selecting a CPR valve? Humidification capacity of the system

What are the two basic types of relief valves used on refrigeration systems? An automatic relief valve and a one-time relief valve

Why is the filter drier important?It keeps the system clean and dry.

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?A check valve

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

The advantage of ball valves over other types of manual refrigeration valves is that they:Offer less resistance to flow.

When installing a solenoid valve:The arrow stamped on the body should point in the direction of flow.

What is the material inside the filter drier called?Desiccant

What does a crankcase pressure regulator do?It will not allow the compressor suction pressure to rise above the CPR set point.

What does an evaporator pressure regulator do?It will not allow the evaporator pressure to drop below its set point, even if the suction pressure is lower.

A suction-to-liquid line heat exchanger:Increases both superheat and subcooling.

What type of systems normally use crankcase pressure regulators?Low-temperature refrigeration applications such as walk-in and reach-in freezers

How can a technician determine when a filter drier is stopped up and needs changing?The pressure drop will exceed 2 psig.

Moisture indicators are normally part of: A sight glass.

Why are liquid-line filter driers required for all systems using HFC refrigerant? Because the POE oil used with HFC refrigerant is very hygroscopic.

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

Why is it necessary to have controls for maintaining a minimum high-side pressure on outdoor air-cooled condensers? Maintain proper head pressures.

Where in the system is an oil separator installed? In the discharge line leaving the compressor

In most commercial refrigeration systems, most of the excess refrigerant that is not being used is stored in: The liquid receiver.

The liquid receiver. Molecular sieve and activated alumina

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

What types of systems use evaporator pressure regulators (EPR)?Systems with multiple evaporators

Filters out moisture and particulates. Liquid line dryer

Removes oil from discharge gas. Oil separator

Indicates liquid level in the receiver. Liquid level sensor

Reduces flash gas in the liquid line. Subcooler

The defrost cycle is normally terminated:Based on either temperature, pressure, or time.

What are the most common desiccant materials used in driers?Molecular sieve and activated alumina

What must be considered when performing a heat load calculation for a walk-in cooler or freezer?Heat transmission, air infiltration, and product load

Why is a check valve installed in the suction line of the lowest-temperature coil in a multiple-evaporator system? To prevent refrigerant migration from the higher-temperature-and-pressure coil to the lower-temperature and-pressure coil

What is commonly used to control defrost operations? Defrost timer

A system that maintains temperatures of -250°F and below is a(n): Cryogenic system.

Three common methods of controlling evaporator temperature are: Conventional thermostat, a suction pressure cut-out control, or an evaporator pressure regulator.

When multiple compressors are installed in parallel on the same refrigeration system, provisions must be made to ensure that: The oil level is correct in all compressors.

What is the approximate ventilation requirement for low-temperature, air-cooled condensing units located indoors? 200 CFM per 1,000 BTU

The first step in selecting commercial refrigeration equipment for a new installation is: Perform a heat load calculation to determine the required BTU capacity of the system.

What refrigeration component makes it possible to use a single compressor to control multiple cases at different temperatures? Evaporator pressure regulator

A refrigerated case that maintains a temperature of 28°F would be classified as: A medium-temperature system.

Why would a 35°F medium-temperature case need to defrost? The coil temperature for a 35°F box operates below freezing.

What are the broad areas that commercial refrigeration equipment is grouped in based on the evaporator coil temperature? High, medium, low, and cryogenic temperatures

What is the purpose of the door switch on a walk-in freezer? To prevent warm air from entering the case by shutting off the fans when the door is opened

The essential elements of a single-component system refrigeration system, in order, are: Evaporator, compressor, condenser, and metering device.

What is the normal storage temperature for food items like milk, cheese, fresh fruits, and vegetables? from 32°F to 40°F

How can a technician determine when a filter drier is stopped up and needs changing? The pressure drop will exceed 2 psig.

What is the material inside the filter drier called? Desiccant

Why should the evaporator NOT be installed above the door in a walk-in cooler or freezer? It will draw in warm, humid air and frost more quickly.

What is the advantage of using multiple compressors on a supermarket rack system? System capacity can match refrigeration loads, which vary over a wide range.

The harvest cycle on an ice machine: Releases the ice cubes after they are made

How is the water level in the reservoir of an ice machine maintained at the correct level? A float switch

How does a cuber typically make the ice cubes? Water is circulated through freezing cells.