Refrigeration & AC - QMED

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

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

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

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

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

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

If the combination moisture indicator and sight glass indicates an accumulation of moisture within the system, which of ...

With a service gauge manifold set connected to a refrigerant compressor as shown in the illustration, which arrangement ...

Which of the hand valve configurations for the gauge manifold set is the correct set up for monitoring both the low and ...

Which of the following leak detectors would be appropriate for use in leak detecting on a system currently pressurized w...

What is a quick method used to test a water-cooled condenser for the presence of a refrigerant leak without actually pin...

Some chlorinated fluorocarbon refrigerants may decompose into a toxic irritating gas under what conditions?

What must be done to use standard leak detection methods on a low-pressure refrigeration system charged with refrigerant...

To test for a suspected large refrigerant leak from an R-22 refrigeration system in an enclosed area, how should this be...

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

If you find a refrigerant leak while using a halide torch, what will happen to the flame as the exploring tube approache...

What is the color of the flame produced by a halide torch when there is no halogenated refrigerant present at the locati...

Moisture is removed from recovered refrigerant using a recycling machine by what means?

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

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?

In reclaiming recovered refrigerant, which type of contamination will the reclamation process be unable to separate? ...

When removing the primary refrigerant from a system using water as a secondary refrigerant, it is important to follow wh...

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

A "hygroscopic" lubricant used in refrigeration compressors would have what characteristic?

What is the most important consideration in selecting a lubricating oil for use in a refrigeration compressor?

The lubrication oil in the crankcase of a refrigeration compressor that is shut down is heated. For what purpose is this...

When checking the oil level in a refrigeration compressor, under what conditions would the most accurate reading be obta...

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

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

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

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

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

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

Which of the following refrigerants is chlorine free and safe regarding atmospheric ozone depletion?

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

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

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

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

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

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

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...

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

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

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

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

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

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

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

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...

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

A thermal expansion valve installed in a refrigeration system is controlled by the action of what device?

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

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

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

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

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

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

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

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

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

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

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

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

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

A liquid sight flow indicator in a refrigeration system is examined and gas bubbles are noted in motion with the fluid f...

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

A refrigeration system is equipped with a reciprocating compressor and a water-cooled condensing unit. If the system is ...

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

One cause of high head pressure occurring in a refrigeration system can be which of the following?

Excessive, prolonged oil foaming in the crankcase of a refrigeration compressor can result in what condition?

Which of the following conditions would indicate that the liquid line strainer in a refrigeration system has become exce...

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

An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet tempe...

If the compressor is heard to knock while pumping down the low side for repairs, but otherwise the compressor sounds nor...

If a refrigeration system compressor crankcase is exhibiting an unusual degree of sweating or frosting and is operating ...

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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...

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

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

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

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

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

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

Which of the conditions listed may be an indication of an excessive amount of refrigerant circulating through the system...

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

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

If an abnormally large difference is maintained between the evaporator refrigerant temperature and the box air temperatu...

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

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

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

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

The color and/or condition of the oil observed in the sight glass of an operating refrigeration compressor experiencing ...

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

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

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

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

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

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

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

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

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

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

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

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

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 refrigera...

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

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

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

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...

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

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

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

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

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

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

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

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

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

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

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

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

At ambient temperature and atmospheric pressure, what is the status of R-134a?

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

Refrigerant entering the compressor of a refrigeration system should be in which of the following conditions?

Regarding heat transfer principles, which of the following are true?

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

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

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

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