Y2A Questions

If the effective voltage is​ 110V, what is the peak​ voltage? A. 187.7V B. 162.5V C. 77.7V D. 155.5V

155.5V

The highest voltage that can be safely applied to a 240V motor is​ _____. A. 250V B. 240V C. 246V D. 264V

264V

The refrigerant class that contains the highest concentration of chlorine is​ _____. A. CFC B. organic C. HFC D. HCFC

CFC

A failed welded hermetic compressor can be​ field-repaired. True False

False

Which compressor type has the lowest capacity in​ tons? A. Screw B. Scroll C. Centrifugal D. Rotary vane

Rotary vane

After a deep​ evacuation, the vacuum gauge slowly rises without stopping. This indicates​ _____. A. normal operation B. moisture in the system C. a vacuum leak D. a bad vacuum gauge

a vacuum leak

Oil that dissolves easily in refrigerant is said to​ be_____. A. synthetic B. miscible C. hygroscopic D. viscous

miscible

The maximum allowable​ leg-to-leg voltage imbalance is​ _____. A. 8% B. 5% C. 2% D. 10%

2%

The voltage imbalance between any two legs of the​ three-phase power supply to a compressor should not exceed​ _____. A. 2% B. 15% C. 5% D. 10%

2%

With an Edison​ hookup, the voltage measured between L1 and L2 should be​ _____. A. 240VAC B. Three-phase C. 120VAC D. 200VAC

240VAC

If a transformer has 600 primary windings and 200 secondary​ windings, what will be the output voltage with an input of​ 120VAC? A. 40V B. 100V C. 60V D. 360V

40V

What level of vacuum must be reached when the deep vacuum evacuation method is​ used? A. 1000 microns B. 29" water column C. 500 microns D. 1500 microns

500 microns

When charging a​ split-system with a long interconnecting line set by​ weight, what, if​ anything, needs to be done to the refrigerant​ charge? A. Add 6 oz. of refrigerant for each extra foot of length. B. Nothing, the factory charge is adequate for long lines. C. Add additional charge per the​ manufacturer's instructions. D. Install an accumulator to hold the extra refrigerant.

Add additional charge per the​ manufacturer's instructions.

Of the​ following, which ​one does not​ cause ​slugging? A. Air in the system. B. Refrigerant overcharge. C. Oversized TXV. D. Buried refrigerant lines.

Air in the system.

Which of the following oils ​is least likely​ to be used with an HFC refrigerant in a comfort cooling​ system? A. PAG B. Alkybenzene C. POE D. PVE

Alkybenzene

Of the​ following, which condition would require system​ evacuation? A. Filter-drier replacement B. Split-system installation C. Compressor replacement D. All the above

All of the above

Where is a​ clamp-on ammeter placed to measure compressor current on a​ single-phase compressor? A. Around the common lead. B. Around all three leads. C. Around the start lead. D. Around the run lead.

Around the common lead.

Which compressor type uses a​ high-speed impeller to compress​ refrigerant? A. Screw B. Centrifugal C. Scroll D. Rotary vane

Centrifugal

Which statement ​is incorrect​ regarding charging liquid refrigerant by​ weight? A. It is a very fast way to charge an empty system. B. Charging is done through the system high side. C. The compressor is off during charging. D. Charging is done through the system low side.

Charging is done through the system low side.

How will a sight glass in an operating system appear when the refrigerant charge is​ correct? A. Bubbling B. Clear C. Flashing D. Foaming

Clear

A temperature differential in a refrigeration system is responsible for creating refrigerant flow in the system. True False

False

Ammonia should not be used as a refrigerant in a system containing copper piping because it will create a toxic gas. True False

False

An ultrasonic leak detector is a good choice for finding very small leaks. True False

False

Any modern electronic leak detector can detect all modern refrigerants. True False

False

Any recovery machine can be used to recover any​ refrigerant, regardless of the type and quantity. True False

False

As long as there is charge in the​ system, a leak test can be performed. True False

False

Current imbalance can only occur if there is a voltage imbalance. True False

False

Disposable cylinders always dispense refrigerant vapor in the upright position. True False

False

It takes at least 10A to cause a fatal shock. True False

False

Splash lubrication uses an oil pump to move oil to the bearings. True False

False

Synthetic oils are popular because they are less hygroscopic than mineral oils. True False

False

The preferred method of adding oil to a system is to pour it into the crankcase. True False

False

The stator of a​ single-phase motor represents a resistive load. True False

False

The​ push-pull refrigerant recovery method is ideal for use on a residential heat pump. True False

False

Unlike​ zeotropes, near-azeotropes can be charged into a system as vapor. True False

False

Which of the following refrigerants contains the lowest concentration of​ chlorine? A. CFC-12 B. CFC-500 C. HCFC-123 D. HCFC-22

HCFC-123

A replacement refrigerant for​ CFC-12 that does not have a glide is​ _____. A. HCFC-409A B. HFC-134A C. HCFC-401B D. HCFC-401A

HFC-134A

The color pink is assigned to refrigerant​ _____. A. HFC-407C B. HCFC-123 C. HFC-410A D. HCFC-22

HFC-410A

How are​ high- and​ low-pressure safety cutout switches connected in a​ circuit? A. In series with the compressor contactor coil. B. In series in the compressor Common lead. C. In parallel with each other. D. In parallel with the compressor

In series with the compressor contactor coil.

Where can the subcooling value for a unit be​ found? A. In the​ unit's service literature. B. On the liquid line service valve. C. Stamped on the metering piston. D. On the suction line service valve.

In the​ unit's service literature.

Which of the ​following does not​ describe a characteristic of a​ semi-hermetic compressor? A. It uses an external drive motor. B. Cylinder heads can be removed. C. It is​ field-repairable. D. The drive motor is hermetically

It uses an external drive motor.

Of the following​ procedures, which ​one would not​ be done as part of a preliminary​ inspection? A. Look for rust or corrosion B. Check for clean air filters C. Measure superheat. D. Check that service valves are open

Measure superheat.

Which of the following is a correct statement regarding refrigerant​ conversion? A. Up to​ 15% mineral oil can remain in a system using synthetic oil. B. HCFC-123 is a​ drop-in replacement refrigerant for​ HCFC-22. C. Mineral oil is compatible with most new refrigerants. D. Mineral oil must be completely purged before installing synthetic oil.

Mineral oil must be completely purged before installing synthetic oil.

Which of the ​following is not​ a factor in determining compressor​ displacement? A. Length of stroke B. Motor type C. Motor Speed D. Number of cylinders.

Motor type

What can occur in a​ dual-compressor system if one compressor runs most of the​ time? A. Condenser overheats B. Evaporator freezes C. Metering device overcompensates D. Oil can be trapped

Oil can be trapped

Where is refrigerant temperature measured when calculating subcooling with a zeotropic​ refrigerant? A. In the center of the evaporator coil. B. In the center of the condenser coil. C. On the suction line at the evaporator. D. On the liquid line at the condenser.

On the liquid line at the condenser.

To leak test a system without​ charge, _____. A. Pressurize slightly with refrigerant and increase pressure with regulated oxygen B. Pressurize the system to 800psi with nitrogen C. Pressurize the system with refrigerant and compressed air D. Pressurize slightly with refrigerant and increase pressure with regulated nitrogen

Pressurize slightly with refrigerant and increase pressure with regulated nitrogen

Which compressor type uses rotors that mesh together to compress​ refrigerant? A. Rotary vane B. Centrifugal C. Screw D. Scroll

Screw

What happens to water when it is placed under a​ vacuum? A. The boiling point increases. B. The boiling point decreases. C. It freezes instantly. D. Ice begins to melt.

The boiling point decreases.

Which statement ​is correct​ regarding the superheat charging​ method? A. The method is used on systems with an expansion valve metering device. B. The method is used on systems with a​ fixed-orifice metering device. C. The system must be off during charging D. Superheat is measured on the liquid

The method is used on systems with a​ fixed-orifice metering device.

Which statement regarding recovery cylinders ​is incorrect​? A. They can be used for system charging. B. They must be dedicated to one refrigerant. C. They can be filled​ 100% with refrigerant. D. They are colored gray with a yellow shoulder.

They can be filled​ 100% with refrigerant.

Which type of induction motor does not have a start​ winding? A. Three-phase B. PSC C. Capacitor start D. ​Split-phase

Three-phase

A compressor​ start-delay timer function is often built into modern room thermostats. True False

True

A disconnect is required for a condensing unit in addition to any fuse or circuit breaker controlling the branch circuit. True False

True

All​ single-phase motors require one or more devices to provide starting torque. True False

True

HFCs such as​ HFC-123 contain no chlorine. True False

True

In a system using two​ compressors, capacity control can be achieved by cycling one of the compressors off. True False

True

Line-duty motor overload protectors directly remove line voltage from the compressor motor. True False

True

Vapor charging by weight can be done with the compressor running. True False

True

When calculating superheat using a zeotropic​ refrigerant, use the dew point column on the​ P-T chart. True False

True

Which test method is most likely to be used on a welded hermetic​ compressor? A. PH test strips B. acid-moisture tester C. acid test kit for oil D. acid-moisture converter

acid-moisture tester

Under normal​ use, change the oil in a vacuum pump​ _____. A. daily B. monthly if used a lot C. after 10 hours of use D. weekly

after 10 hours of use

When performing system operational​ checks, always​ _____. A. record temperatures and pressures B. compare readings to records C. follow safety instructions D. all the above

all the above

The bubble point is the point at which refrigerant​ _____. A. begins to condense when heated B. becomes superheated when heated C. begins boiling when heated D. stops evaporating when heated

begins boiling when heated

The type of​ single-phase motor used to drive compressors is the​ _____. A. capacitor​ start-capacitor run B. PSC C. capacitor start D. shaded pole

capacitor​ start-capacitor run

When charging a zeotropic blend into an operating​ system, always​ _____. A. charge with liquid through a metering device B. charge with liquid directly into the high side C. charge with liquid directly into the low side D. charge with vapor directly into the high side

charge with liquid through a metering device

Most electricity produced by public utilities comes from _____. A. nuclear power plants B. wind farms C. solar energy D. coal-fired power plants

coal-fired power plants

Once system operational checks have been​ taken, the next step is to​ _____. A. compare readings to normal readings B. replace the compressor C. turn off electrical power D. remove refrigerant

compare readings to normal readings

Compressor lubricating oil is stored in the​ _____, A. receiver B. muffler C. compressor shell sump D. accumulator

compressor shell sump

In the refrigeration​ cycle, the compressor​ _____. A. converts​ low-pressure vapor into​ high-pressure vapor B. converts​ high-pressure liquid into​ high-pressure vapor C. converts​ low-pressure liquid into​ high-pressure vapor D. converts​ low-temperature liquid into​ high-pressure vapour

converts​ low-pressure vapor into​ high-pressure vapor

After the first and second evacuations of the triple evacuation​ method, the system is pressurized with​ _____. A. refrigerant B. compressed air C. regulated oxygen D. dry nitrogen

dry nitrogen

An overload that employs thermistors embedded in the motor windings is called​ a(n) _____. A. current monitoring device B. external line break overload C. electronic overload D. motor thermostat overload

electronic overload

The alteration of a zeotropic blend caused by system leaks is​ called_____. A. breakdown B. fractionation C. glide D. alteration

fractionation

The resistance to ground of a​ 460-volt motor is measured at​ 500,000 ohms. This indicates​ a(n) _____. A. grounded motor B. open motor C. shorted motor D. good motor

good motor

A capacity control method that holds the suction valve open is called​ _____. A. suction cutoff unloading B. hydraulic unloading C. suction bypass unloading D. hot gas bypass

hydraulic unloading

Flooded starts can be minimized by​ _____. A. overcharging the system B. installing a crankcase heater C. installing a start capacitor and relay D. removing​ 10% of the crankcase oil

installing a crankcase heater

The suction valve in a reciprocating compressor is open during the​ _____. A. intake stroke B. power stroke C. exhaust stroke D. compression stroke

intake stroke

A transformer with a​ 1:1 turns ratio that protects people and equipment is called​ a(n) _____. A. step-down transformer B. three-phase transformer C. isolation transformer D. distribution transformer

isolation transformer

Air entering the refrigeration system is considered a contaminant because​ _____. A. it can contain moisture B. it contains acid C. it thins the oil D. it is dirty

it can contain moisture

An advantage of a​ three-phase motor over a​ single-phase motor is​ _____. A. reduced weight B. lower voltage run capacitor needed C. less running pulsations D. smaller start capacitor needed

less running pulsations

Oil mixed with refrigerant in a refrigeration system is used to​ _____. A. permit refrigerant to flow easier B. lubricate the expansion valve C. lubricate compressor parts D. prevent metering device​ freeze-up

lubricate compressor parts

Superheat is calculated by subtracting the saturation temperature from the​ _____. A. subcooling temperature B. condenser temperature C. outdoor temperature D. measured temperature

measured temperature

Centrifugal compressors achieve capacity control by​ _____. A. cylinder unloading B. moving inlet guide vanes C. on/off cycling D. hot gas bypass

moving inlet guide vanes

If the overload protector stops compressor operation by opening the compressor​ contactor, the overload protector is​ a(n) _____. A. external line break B. internal line break C. pilot-duty device D. line-duty device

pilot-duty device

For good oil​ return, suction lines should be​ _____. A. pitched toward the compressor B. pitched away from the compressor C. nearly vertical D. as level as possible

pitched toward the compressor

A fusible link may be used to​ _____. A. protect the secondary from excessive current B. protect the primary from voltage surges C. physically connect the primary and secondary D. protect the secondary from overheating

protect the secondary from excessive current

Refrigerant that has been restored to​ factory-specified levels of cleanliness for new refrigerant has been​ _____. A. rehabilitated B. reclaimed C. recovered D. recycled

reclaimed

Refrigerant that has been removed from a unit and put into temporary storage has been​ _____. A. recycled B. reclaimed C. rehabilitated D. recovered

recovered

A compressor lockout circuit prevents​ _____. A. current surges B. repeated compressor cycling C. unauthorized system operation D. voltage fluctuations

repeated compressor cycling

A transformer with a 120VAC primary and a 24VAC secondary would be found in​ a(n) _____. A. packaged rooftop unit B. room air conditioner C. heat pump air handler D. residential gas furnace

residential gas furnace

For any​ refrigerant, the​ P-T chart shows the​ pressure/temperature relationship at​ _____. A. sea level B. atmospheric pressure C. saturation D. superheat

saturation

Valves in the cylinder heads of a compressor are held closed by​ _____. A. discharge pressure B. head pressure C. suction pressure D. spring tension

spring tension

The motor windings of a welded hermetic compressor are cooled by​ _____. A. suction gas B. air C. water D. liquid refrigerant

suction gas

The type of oil most widely used with HFC refrigerants is​ _____. A. synthetic B. mineral C. organic D. petroleum-based

synthetic

A​ leak-detecting dye can be seen with​ a(n) _____. A. ultraviolet lamp B. flashlight C. ultrasonic lamp D. halide torch

ultraviolet lamp

When recovering​ R-410A from a​ system, always​ _____. A. replace recovery machine oil only if it is contaminated B. use a recovery machine designed to recover​ R-410A C. replace recovery machine oil with POE oil D. replace recovery machine oil if the machine recovered a different refrigerant

use a recovery machine designed to recover​ R-410A

If oil becomes contaminated with​ moisture, the moisture must be removed​ _____. A. using a​ filter-drier B. by removing the oil C. heating the crankcase D. using a vacuum pump

using a​ filter-drier

Glide occurs in​ _____. A. azeotropes only B. near-azeotropes only C. zeotropes and​ near-azeotropes D. zeotropes only

zeotropes and​ near-azeotropes

Which of the following​ three-phase configurations will provide 480​ volts? A. Four-wire open delta B. Four-wire wye C. Three-wire wye D. Four-wire closed delta

​Four-wire wye

The refrigerant that is a​ drop-in replacement for​ CFC-502 is​ _____. A. HFC-404A B. HFC-410A C. HCFC-22 D. HFC-407C

​HFC-404A