Refrigeration & AC - 1st Asst/Chief

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

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

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

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

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

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

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

What would be an indication that the vegetable box back pressure regulator is set too low?

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

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...

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

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

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

Corrosion has wasted away large sections of the fins attached to an air conditioning cooling coil. In assessing the effe...

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

The rupture disc on a low pressure centrifugal refrigeration unit is used as an over pressure protection device and is s...

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

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 ...

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

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

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

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

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

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

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

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

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

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

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

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

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

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?

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

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?

While securing the air conditioning compressor you close the suction valve and the compressor stops after a short period...

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

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

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...

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

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

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

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?

A reheater in an air conditioning system performs what function?

EPA Clean Air Act rules permit refrigerant to be released to the atmosphere under which of the following conditions? ...

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

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

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

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

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

Which best defines a "Type I" small refrigeration appliance according to the EPA Regulations Section 608?

According to the EPA Clean Air Act rules, what is true concerning refrigerant leaks in a small hermetically sealed shipb...

When recovering R-12 from a small appliance with a working compressor, using a recovery device manufactured after Novemb...

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

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

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

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

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

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

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

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

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

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

The air temperature associated with a direct reciprocating air conditioning plant is found to be too warm, and the compr...

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

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

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

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

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

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...

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

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

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

A reciprocating multi-cylinder air conditioning or refrigeration compressor starts cycling on/off. What would one do to ...

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

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

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

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

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

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

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

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

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

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

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

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

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

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?

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

As shown in the illustrated LP centrifugal chiller pressure maintenance system, what is its functional purpose? Illustra...

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

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

As shown in the illustrated flow diagram for a self-contained recovery unit designed for the recovery of refrigerants fr...

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

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

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?

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

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

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

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 ...

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

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

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?

Rather than design an infinite variety of thermostatic expansion valve sizes to accommodate different capacities for hea...

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

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

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

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

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

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

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

Which of the statements listed is applicable to the thermostatic expansion valve shown in the illustration? Illustration...

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

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

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

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

Refrigerant flow through a thermostatic expansion valve is greatest under what conditions?

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

When a refrigeration compressor is in the 'off' cycle, the thermal expansion valve will react in what way?

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

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

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

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

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

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

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

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

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

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

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

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

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...

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

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

The introduction of outside air to the air conditioning system is 90°F with a relative humidity of 60%. The air has been...

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

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

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

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

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

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

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?

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

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

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

Personnel servicing refrigeration systems that exposes them to commonly used refrigerants should wear what type of perso...

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

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

While troubleshooting intermittent failures of the ship service refrigeration system you suspect the problem is with the...

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

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?

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

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 ...

The compressor on the ships service refrigeration system starts up but stops after a brief period of running. Subsequent...

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

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

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

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

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

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

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

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

Refillable tanks used to ship CFC and HCFC refrigerants or used to recover these refrigerants must meet the standards of...

Coast Guard Regulations

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

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

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

What maintenance may be carried out on a 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 ...

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

Expansion valve maintenance should include which of the following procedures?

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

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

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

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

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

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

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?

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

While recharging a commercial type refrigerator, with a hermetically sealed compressor with no pressure gauges, what cou...