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.

Select the characteristics of a cube ice machine. Alternating ice making and harvest cycles, Large rectangular evaporator, Uses hot gas bypass to release ice from the evaporator

Which ice is often added to drinks and is easy to chew? Crushed ice

How is the ice removed from the vertical evaporator plate after it reaches the proper thickness? The compressor continues to operate and a hot gas solenoid sends hot discharge gas to the evaporator.

What is the difference between crushed ice and flake ice? crushed ice is made as a cube and mechanically crushed.

What is the possible cause for ice sticking and not releasing during the harvest cycle? A dirty evaporator

What could cause corrosion of a stainless-steel ice-maker? Acidic water or too much chlorine gas in the water supply

Ice machine cleaning and sanitizing: Are separate processes required for two different solutions.

How is ice quality measured? Ice quality is measured in percentage of hardness.

The amount of ice required for a restaurant is approximately: 3 lbs. per person.

What is the purpose of a photo-electric eye on an ice machine? The photo-electric eye detects when no ice production has occurred and shuts down the unit, even if the bin is not full.

Most flake ice machines utilize this type of evaporator. A vertical, cylindrical, tube-shaped stainless-steel evaporator

What can cause odors or slime build-up in an ice machine? Odor and slime build-up are caused by bacteria and fungi growth.

Select the characteristics of cubed ice. You may select more than one. Clear,Slower melting,95 percent hardness

To prevent mineral buildup and scale on an ice machine: Use a water filter to remove suspended solids.

Circulating water over the evaporator while the ice is freezing:Keeps air bubbles and solids from freezing in the ice.

The amount of ice required for a salad bar is approximately. 30 lbs. per cubic foot.

One common method of determining when the ice bin is full is: An ice level probe.

What are some differences between a flake ice machine and a cube ice machine? The flake ice machine has a vertical cylindrical evaporator and makes ice continuously, while the cube ice machine has a horizontal rectangular evaporator and makes ice in cycles

Ice that has the appearance of snow is called: Shaved ice.

Ice machine capacity is normally stated as: Pounds of ice per day.

How is the ice removed from the evaporator of a flake ice machine? A slow-turning spiral-fluted auger cracks the ice off.

What are six applications for a commercial ice machine? Restaurants, cafeterias, hotels, hospitals, cruise ships, and theme parks

To check the condition of the compressor's motor windings, a technician will need to measure the resistance of the windings using a standard: Ohmmeter.

Select possible cause(s) of an iced-up evaporator on a commercial freezer. You may select more than one.Bad evaporator fan motor, Open defrost heaters, Shorted defrost termination switch, Bad defrost timer motor

To check for electrical potential at a switch or a load, technicians use a(n): Voltmeter.

Why should the temperature inside the compressor be kept under 300°F? Because the compressor oil starts to break down above 300°F

To increase the operating superheat on a thermostatic expansion valve: The adjusting stem should be turned clockwise.

The contacts of a current starting relay are: Normally open.

On run capacitors, any sign of bulging of its body is a sign of a(n) ________ capacitor. bad

The current relay coil is wired: In series with the run winding.

The correct way to discharge a capacitor is: To touch both ends of a 20 kΩ, 5 W resistor across the terminals.

To manually defrost a frozen evaporator coil, technicians should: Use a heat gun to accelerate the melting of the ice.

How does accumulated dirt on the condenser coil affect system operation? Raises the condenser pressure and temperature

What is the best way to warm a refrigerant cylinder? In a bucket of warm water

One basic rule a technician must follow while searching for a leak is to: Have patience.

To check the amount of electrical current a load is drawing, technicians use a(n): Ammeter.

A reciprocating compressor with leaking valves will operate with: A low amp draw, high suction pressure, and low head pressure.

When troubleshooting single-phase compressor motors, it is important that the technician: Check the start relay, start capacitor, and run capacitor.

To safely increase the pressure in a refrigerant cylinder while charging a system, the technician should:Run warm water over the cylinder.

To safely increase the pressure in a refrigerant cylinder while charging a system, the technician should: The contacts in a potential relay are: Normally closed.

When replacing or repairing any electrical components, always verify that the: Power source is disconnected and locked out.

What visual clues on a system can indicate the presence of a refrigerant leak? Oil stains around the area of the leak

A suction superheat measurement lower than the manufacturer's recommended superheat setting indicates that: Too much refrigerant is being fed into the evaporator.

What effect do noncondensable gasses have on system performance? They cause an increase in head pressure and a decrease in capacity.

Electrical components can generally be divided into two groups: Controls and loads.

A suction superheat measurement higher than the manufacturer's recommended superheat setting indicates that: Too little refrigerant is being fed into the evaporator.

The potential relay coil is wired: In parallel with the start winding.