Refrigeration & AC - Assistant Engineer

When repairing a refrigeration system, a swaging tool set would be used to carry out which of the following operations? ...

In a refrigeration system that is not protected by a water failure switch, if the cooling water to the condenser fails, ...

When the relief valve opens on a refrigeration compressor discharge line, it discharges high-pressure refrigerant vapor ...

Which of the lettered components shown in the illustration indicates the high-pressure cutout? Illustration GS-RA-12 ...

The rupture disc on a low-pressure centrifugal refrigeration unit is used as an overpressure protection device and is se...

During the initial cooling down of a box temperature in a refrigeration system, which of the devices listed is used to p...

A reheater in an air conditioning system performs what function?

What is one benefit of maintenance of proper air circulation in an air conditioned cargo space?

In a two stage centrifugal air conditioning system, the liquid refrigerant passes through the condenser directly to what...

In an air conditioning system, what is the name of the chamber where the duct-work originates?

What is the wet bulb temperature of air if the dry bulb temperature of the air is 90 degrees and the relative humidity i...

In general, the thermal bulb for a thermal expansion valve used in a reciprocating air conditioning system is usually ch...

Heat is removed from the refrigerant circulating through the refrigeration system, shown in the illustration, by which c...

Sea water or low temperature central fresh water is typically provided to a ship's stores refrigeration plant for what p...

Zinc plates commonly found in refrigeration systems and used as sacrificial anodes are located where?

Vapor bubbles present in the liquid upon arrival to the thermal expansion valve in a refrigeration system may cause eros...

Moisture entering a typical refrigeration system will most likely produce what effect?

A small obstruction at the thermostatic expansion valve inlet will result in which of the following conditions?

An obstructed expansion valve may be indicated by an incompletely cooled evaporator and what other symptom?

Which of the following conditions will occur if the power element of the thermostatic expansion valve shown in the illus...

If the needle and seat assembly is excessively eroded, the valve cage assembly can be replaced. In replacing the origina...

If the superheat value of the thermostatic expansion valve is adjusted too high, what would be the result?

If the superheat setting of a thermostatic expansion valve is set too low, what would be the result, assuming that the s...

Which of the illustrated valves is used to gain access to a hermetic system and features a Schrader core valve which is ...

How should small appliances with less than three pounds of refrigerant be charged with refrigerant?

Before charging a refrigeration unit, unless quick disconnect fittings are used, the refrigerant charging hoses should b...

Which of the illustrated devices would be the LEAST accurate for the purposes of weighing-in a refrigerant charge? Illus...

Concerning the charging of refrigerant into a vapor compression refrigerating system, which of the following is true? ...

Which of the following illustrated expansion valves is designed to maintain a constant evaporator pressure rather than a...

Within the territorial limits of the United States, violations of the Clean Air Act of 1990, that includes the intention...

All shipboard personnel responsible for the maintenance and repair of air conditioning systems using refrigerants covere...

Persons recovering refrigerant from small appliances must be certified as what type of technician under the EPA Clean Ai...

What would be an example of a small appliance as defined in the EPA Clean Air Act rules?

If you find the pressure of a refrigeration system containing a Class I or Class II refrigerant to be opened for the ac...

Excessively tight drive belts installed between a motor and a refrigeration compressor pulley may cause what condition? ...

When installing a mechanical shaft seal on a refrigeration compressor, extreme care must be taken to prevent what from h...

If the discharge reed valves used in a refrigeration compressor are leaking badly, what statement is true?

When one belt of a multiple V-belt drive requires replacing, what will be required?

In addition to the drive belt itself, a V-belt that is tensioned too tight will cause excessive wear to what other drive...

On a modern refrigerated container unit employing suction modulation for the purposes of capacity control and capacity l...

To prevent motor overload during start-up of a hermetically sealed centrifugal refrigeration system, what is true conce...

The fluid used as a source of actuating power against the underside of the unloader power element piston of the refriger...

A refrigeration compressor used in a multi-box refrigeration system is designed with six of its eight cylinders able to ...

During operating periods of a multi-box refrigeration system using a capacity controlled compressor, when all of the eva...

Capacity control of a centrifugal refrigeration compressor can be accomplished by what means?

Why is a purge recovery unit typically fitted on low-pressure centrifugal chillers?

Minor repairs may be performed on low-pressure refrigerant systems without recovering the refrigerant charge if the pres...

The most cost-effective method of recovering refrigerant from a low-pressure chiller with more than 500 lbs. of refriger...

As shown in the illustrated refrigeration system piping schematic diagram with the various accessories and controls and ...

In a refrigeration system, the valve shown in the illustration is used for what purpose? Illustration GS-RA-14

An arrow stamped on the valve body of a water regulating valve indicates which of the following?

The set point adjustment of the device shown in the illustration is made by rotating what component? Illustration GS-RA-...

If it is necessary to increase the operating head pressure of the refrigeration system using the device shown in the ill...

If the valve labeled "D" in the illustration is a suction service valve, what will the port labeled "7" be connected to?...

In addition to pressure, most compound and standard pressure gauges used for refrigeration service are also provided wit...

In a large refrigeration system having more than one evaporator, a king solenoid valve should be installed in what locat...

Refrigeration system isolation valves are specially designed with a backseat, as well as a front seat. For what purpose ...

In addition to the indicated gauge pressure, what other information is presented on the compound gauge for the hypotheti...

What is the purpose of the pressure transducer as shown in the illustration? Illustration GS-RA-17

The receiver used in a refrigeration system performs what essential function?

Hard drawn copper tubing is commonly used in larger refrigeration systems. What statement concerning its use is true? ...

Which lettered component, shown in the illustration, indicates the location of the receiver? Illustration GS-RA-12 ...

In a refrigeration plant, what is one vital purpose of the receiver?

In a refrigeration system, from what location would air and non-condensable gases be removed?

Loss of refrigerant during the process of purging of air and non-condensable gases can be kept to a minimum by what acti...

In a low-pressure centrifugal chiller, what is meant by the term 'high efficiency purge unit?'

During normal operation, traditionally, how has most of the refrigerant released to the atmosphere from low-pressure sys...

For most multi-box refrigeration systems, the refrigerant sight glass would be located where in the system?

A liquid indicator sight glass is useful in determining whether or not a refrigeration system is sufficiently charged. W...

Why are dehydrators usually located in the liquid line of refrigeration systems?

The device shown in the illustration which is used for removing moisture from the liquid refrigerant in the system is la...

Which of the devices listed will indicate whether or not a refrigeration system's dehydrator continues to be capable of ...

Which of the following dehydrators or combination filter/driers features a core that can be replaced when the desiccant ...

The primary purpose of the liquid line strainer used in a refrigeration system is to prevent dirt and scale from enterin...

Moisture is removed from a refrigeration system by what action?

Standard filter/driers used in many commercial type refrigeration units may contain what type of substance?

In a refrigeration system, silica gel is found in what component?

The safety heads of most large reciprocating compressors used in refrigeration systems are held in place by what means? ...

The carbon seal ring of a refrigeration compressor crankshaft mechanical seal is held in position against the stationary...

In the illustrated refrigeration system, what is the proper name for the component labeled "A"? Illustration GS-RA-12 ...

A device used to hold open the refrigeration compressor suction valve during starting to reduce the compression load is ...

What is the drive arrangement of refrigeration compressor shown in figure "B" of the illustration? Illustration GS-RA-41...

Which of the valves listed is normally closed when charging the refrigeration system through the high side?

Using the device shown in the illustration, which of the following statements is true when adding refrigerant as a vapor...

When a refrigeration system is being topped off with a small amount of refrigerant through the low side with the compres...

After the refrigerant has been recovered, leaks repaired if necessary, the system ideally should undergo a dehydration e...

For the proper control of the air temperature in an air conditioning system using chilled water circulation, which of th...

In an air conditioning system, moisture is removed from the air by what means?

A room humidistat initiates the lowering of the humidity of the conditioned supply air to a space, while the actual proc...

To prevent the unnecessary loading of an air conditioning system while maintaining the designed dry bulb temperature and...

Which of the following is true concerning the class "D" air conditioning system shown in the following illustration? Ill...

Which of the following is true concerning the class "A" air conditioning system shown in the illustration as used to con...

If outside air at 80 degrees F and 70 percent relative humidity is conditioned, what will be the resulting dew point tem...

Concerning the arrangement of equipment and associated hoses shown in the illustration, what statement is true? Illustra...

Which of the processes listed would be the most satisfactory method to use to lower the humidity of the air being circul...

Which of the following methods is normally used to control the circulated air temperature of an air conditioning system ...

Using the illustrated chart giving the boiling point of moisture at various depths of vacuum, with an ambient temperatur...

When pumping down an air conditioning system to test the low-pressure cutout switch, assuming that the compressor is run...

When recovering the remaining R-134a refrigerant from the centrifugal chiller shown in the illustration as a vapor using...

The compressor used in a water-cooled air conditioning system is short cycling. A service check determines that the suct...

To add small amounts of refrigerant to the low side of an air conditioning system, the refrigerant should be introduced ...

To add refrigerant to the high side of an air conditioning system, you should close the king valve and introduce the ref...

Concerning the arrangement of equipment and associated hoses shown in the illustration, what statement is true? Illustra...

A reciprocating refrigeration compressor may be tested for leaking discharge valves by stopping the compressor, turning ...

Leaking suction valves in a refrigeration compressor are indicated by which of the following?

Unusual noise coming from a refrigeration compressor can be caused by which of the following conditions?

Which of the listed statements describes the reason why oil foaming occurs when starting a refrigeration compressor? ...

Refrigeration systems using forced air circulation evaporators have a tendency to cause rapid dehydration of produce in ...

In a refrigeration system, what component is installed directly downstream of the thermal expansion valve?

In a dry-type direct expansion refrigeration evaporator, what is true concerning the evaporator coils?

If the evaporator coil horizontal return line of a container refrigeration system is less than 0.875"

Which of the installation steps listed is necessary for the proper operation of the thermostatic expansion valve?

Which of the listed statements describes the method used to determine the amount of superheat present in the suction gas...

The coil temperature measured at the expansion valve sensing bulb of an operating system is 10°F. The low side pressure ...

Expansion valve maintenance should include which of the following procedures?

When replacing a thermostatic expansion valve power element, what is true concerning the thermal bulb?

What maintenance may be carried out on a thermostatic expansion valve?

A thermostatic expansion valve is properly controlling evaporator superheat. Adjusting this valve to lower the evaporato...

Which statement about calibrating a newly installed thermostatic expansion valve is correct?

Of the various possible methods shown in the illustration, which is the correct method of attaching a TXV feeler bulb to...

Which of the following statements describes the accepted method for testing a thermostatic expansion valve?

When a thermostatic expansion valve is installed in a refrigerated container unit, the sensing bulb almost always requir...

What is true concerning the accumulation of air and other non-condensable gases in a refrigeration system?

Charging liquid HCFC-123 into a system under a deep vacuum could cause what to happen unless necessary precautions are t...

Which of the following statements is correct concerning the testing of an R-22 refrigeration system for leaks in an encl...

When using nitrogen to pressure leak test a system, the nitrogen cylinder should always be equipped with what device or ...

A high-pressure centrifugal chiller currently charged with R-134a is being evaluated for the need for leak testing. Usin...

A refrigeration unit will tend to short cycle when operating under what conditions?

If a refrigeration system, equipped with a reciprocating compressor, has a liquid-line solenoid valve that is leaking du...

Moisture in a refrigeration system can cause which of the following conditions?

If a refrigeration compressor had developed a slightly high suction pressure accompanied with an abnormally low suction ...

When a refrigeration compressor motor fails to start, the FIRST thing that should be checked for is what?

In a low-pressure refrigeration system, excessive running of the purge recovery unit generally indicates which probable ...

If the refrigeration compressor crankcase is sweating or frosting and is operating with an unusual noise, what is most l...

If a refrigeration system were short of refrigerant, besides an elevated box temperature, what would be an observable sy...

If a refrigeration compressor were short cycling on the low-pressure cutout switch, what is the most probable cause? ...

An excessive charge of refrigerant in a thermostatically controlled, air-cooled, refrigeration system using a TXV as an ...

If a refrigeration compressor using a thermostat as a primary controller is running continuously without significantly l...

Excessive moisture being collected in the purge unit of a low-pressure refrigeration system could indicate which probabl...

An evaporator coil of a single evaporator, air-cooled refrigerator is accumulating excessive frost due to a failure of t...

During tests to discover why a refrigeration compressor is running continuously, it is determined that the refrigerated ...

As shown in figure "B" of the illustrated self-contained recovery unit connection diagrams, what is the recovery method ...

In a refrigeration system, the push-pull technique can be used for the recovery of the refrigerant in what state?

What is the correct color-coding of refrigerant recovery cylinders regardless of the refrigerant contained within?

What must be done, at a minimum, before a system can legally be opened up for repairs while adhering to the prohibition ...

The gas that exists in the stratosphere forming a protective shield that helps to protect the environment from the harmf...

Which of the following substances is normally classified as a low-pressure refrigerant?

What is the color-coding for a storage container of R-134a refrigerant?

The "tare weight" of a refrigerant storage cylinder refers to what weight?

Alkyl benzene ISO 32 cSt synthetic refrigerant oil is miscible and suitable to use with which of the following refrigera...

The amount of HCFC-123 in a storage cylinder is measured by what means?

Traditionally, which of the listed refrigerants has been more suitable than the others for use in a centrifugal refriger...

Which of the fluids listed is suitable for use as a secondary refrigerant?

According to 46 CFR, Part 58, for protection purposes, what is required of all refrigeration systems?

Coast Guard Regulations

With regards to shipboard refrigeration systems, after July 1, 1992, what action became illegal?

Coast Guard Regulations

When opening or closing compressor service and line isolation valves on a typical refrigeration system that is fitted wi...

What is the purpose of running a refrigeration compressor in short intermittent spurts or throttling the suction isolati...

When starting a reciprocating refrigeration compressor that has been shut down for a period of time, you should manually...

Concerning the operation of refrigeration systems, frosting or sweating of a liquid line is usually indicative of what c...

The surging that occurs in a centrifugal air conditioning compressor is a result of what conditions?

In an air conditioning system, low discharge head pressure associated with a reciprocating compressor can be the result ...

As shown in the illustrated LP centrifugal chiller high efficiency purge recovery unit piping schematic, what statement ...

Sludge may form in the crankcase of an air conditioning compressor as a result of what condition?

The pressure in the part of a high-pressure refrigeration system about to be opened for a non-major repair should be bro...

What is the maximum volume to which refillable refrigeration cylinders should be filled?

You are checking the supply chilled water temperature thermistor probe on a high- pressure hermetic centrifugal chiller....

A box solenoid valve used in a refrigeration system should be installed in what manner?

The FIRST thing to do to ensure that a refrigeration unit will not start while undergoing repairs is to do what?

Which of the precautions listed should be taken before opening any part of a refrigeration system for the purpose of acc...

When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, what should ...

In a refrigeration system, the bulb for the thermal expansion valve is always located where?

In a refrigeration system, the pressure within the power element of a thermostatic expansion valve depends directly upon...

What is one function of the thermal expansion valve used in a refrigeration system?

Which of the following illustrated thermal expansion valves would be appropriate to use on an evaporator coil with a 2 p...

In a vapor compression type refrigeration cycle, the refrigerant temperature decreases the most when passing through whi...

When the sensing bulb of a thermostatic expansion valve is charged with a fluid different from the charge used in the sy...

Through which of the components shown in the illustration is flash gas formation a normal occurrence? Illustration GS-RA...

The thermostatic expansion valve in a refrigeration system further opens when the diaphragm flexes downward. With all ot...

A typical shipboard domestic multi-box refrigeration system operates with one compressor and condenser. What is the purp...

Which of the following illustrated expansion valves is designed to maintain a constant evaporator pressure rather than a...

Besides the evaporator pressure, the thermal expansion valve reacts directly to changes in what parameter?

Constant superheat is maintained at the evaporator coil outlet of a refrigeration system or unit by the action of what d...

Concerning the proper installation of the sensing bulb of a thermal expansion valve that is attached to the evaporator t...

In the multi-evaporator refrigeration system shown in the illustration, what is the proper name for the valve labeled "2...

In refrigeration systems with multiple evaporators, the metering of refrigerant to each refrigerated space evaporator is...

An air-cooled refrigerated container unit using R-134a as a refrigerant has a box temperature set point of -15°F, but it...

Which of the conditions listed could cause excessively low refrigerant pressure at the compressor suction of a TXV contr...

High suction pressure accompanied by low suction temperature to a refrigeration system compressor is caused by which of ...

Low compressor head pressure in a refrigeration system can be caused by which of the following?

If the running suction pressure at the refrigeration compressor of a TXV controlled air- cooled refrigeration system is ...

In an operating, water-cooled, multi-box refrigeration system, both low discharge and high suction pressures are being s...

If increasing the cooling water flow to a refrigeration condenser fails to lower the condenser pressure, the probable ca...

Which of the following statements is true concerning the illustrated gauge manifold set? Illustration GS-RA-01

Which of the following statements is true concerning the gauge labeled "A" of the illustrated gauge manifold set? Illust...

Which of the illustrated gauges is capable of measuring vacuums at the micron level for the purpose of proving system de...

What is true concerning frost build-up on the evaporator coils of a multi-box direct expansion refrigeration system? ...

Some 'hot gas' defrost systems reheat the refrigerant just prior to its returning to the compressor for what purpose? ...

What is the physical state and pressure condition of refrigerant as it enters the condenser of a typical refrigeration s...

What is the pressure and condition of the refrigerant entering the receiver of a refrigeration system?

The term 'oil foaming' in refrigeration practice, is used to describe what event?

What is the physical state and pressure condition of refrigerant as it leaves a receiver in a typical refrigeration syst...

If passive recovery is used on a small appliance fitted with a capillary tube as a metering device with a non-operating ...

Technicians servicing small refrigeration appliances can employ what type of recovery equipment?

Which recovery procedure should be used to minimize the loss of oil from the system during the recovery of refrigerant f...

What is true concerning highly contaminated refrigerant recovered from burned out small appliances?

For safe storage, the maximum allowable temperature to which refrigerant bottles should be exposed is what temperature? ...

Overfilling a refrigerant container is extremely dangerous because of the high pressures generated. The generation of pr...

Personnel servicing refrigeration systems and subject to the exposure to commonly used refrigerants should wear what typ...

Why can CFC or HCFC refrigerants leaking into a confined space or in limited surroundings cause suffocation?

In the presence of an open flame or hot surfaces, chlorinated fluorocarbon refrigerants decompose and form what chemical...

The low-pressure cutout switch settings vary with the refrigerant used and the temperature application. If the low-press...

A container unit's microprocessor-controlled temperature controller is set at -28.9°C, appropriate for a frozen cargo of...

The sensing line for the low-pressure cutout switch for a refrigeration system is typically connected at what location? ...

In a multi-evaporator refrigeration system, a solenoid valve is installed in the liquid line prior to what device?

Which of the following statements is true? Illustration GS-RA-12

What is the purpose of the low-pressure cut-out switch as used as a primary controller for a refrigeration system or uni...

The thermostat controlling the operation of the solenoid valve to a refrigerated box evaporator senses what temperature?...

A box solenoid valve used in a multi-box refrigeration system is operated by electromagnetic action by what control devi...

Which of the listed operations will cause an automatically controlled refrigeration compressor to restart if the system ...

In a refrigeration system featuring low-side pump down prior to the automatic shut down of the compressor, the temperatu...

Which of the following electrically operated refrigeration system valves would be most appropriate for use as a 2 posit...

How does a refrigeration solenoid valve differ from a modulating valve?

A liquid line solenoid valve controls refrigerant flow to the evaporator by what means?

If a condenser coil of an air-cooled container refrigeration system becomes dirty and requires cleaning, what would be a...

When checking zinc plates or pencil zincs in the refrigerating system condenser, what should you do?