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310)
310)
What may be safely used to check a system for leaks at pressures of around 100 psig?
A)
Hydrogen
B)
Nitrogen
C)
Oxygen
D)
Neon
Answer:
B
Explanation:
A)
B)
C)
D)
311)
311)
Placing equipment directly on ceiling joists:
A)
Voids the warranty.
B)
Is against code.
C)
Causes structural damage.
D)
Amplifies the equipment noise.
Answer:
D
Explanation:
A)
B)
C)
D)
312)
312)
When charging systems with zeotropic refrigerants, such as R410A, the refrigerant must leave the
refrigerant cylinder:
A)
Under a pressure of at least 100 psig.
B)
As a liquid.
C)
As a liquid-vapor mixture.
D)
As a vapor.
Answer:
B
Explanation:
A)
B)
C)
D)
313)
313)
The minimum clearance to allow for the front of the service access panel on equipment installed in
an attic is:
A)
A 36" × 36" level area.
B)
A 30" × 30" level area.
C)
A 24 " × 24" level area.
D)
A 12" × 30" level area.
Answer:
B
Explanation:
A)
B)
C)
D)
81
314)
314)
Which of the following statements concerning standards and codes is correct?
A)
Standards are enforced at a national level.
B)
Standards describe the industry's best practices.
C)
Codes are generally broken into five areas: electrical, plumbing, mechanical, refrigeration,
and other.
D)
Codes are written by government agencies.
Answer:
B
Explanation:
A)
B)
C)
D)
315)
315)
Of the four phases listed below, which one is only performed on an "as-needed" basis?
A)
Operation check
B)
Prestart check
C)
Troubleshooting
D)
Routine maintenance
Answer:
C
Explanation:
A)
B)
C)
D)
316)
316)
The most common time to perform a seasonal check on cooling equipment is in the:
A)
Winter.
B)
Summer.
C)
Spring.
D)
Fall.
Answer:
C
Explanation:
A)
B)
C)
D)
317)
317)
What is the purpose of checking the supply voltage after starting the system?
A)
To determine which power leg is positive and which is negative
B)
To determine the refrigeration coefficient of performance crop
C)
To determine the voltage drop in the wire
D)
To verify that the supplied voltage is within the manufacturer's specifications
Answer:
C
Explanation:
A)
B)
C)
D)
82
318)
318)
A technician notes that an operating air-conditioning system has ice formed on the suction line at
the condensing unit. The technician can reasonably assume that:
A)
The refrigerant charge is low.
B)
The condenser coil also is frozen over.
C)
The refrigerant charge is high.
D)
The evaporator coil also is frozen over.
Answer:
D
Explanation:
A)
B)
C)
D)
319)
319)
Why is planned maintenance often performed during the off-season?
A)
You can usually perform the maintenance without having to shut off the system.
B)
Most equipment fails during the off season.
C)
For more efficient use of service labor hours
D)
There are more daylight hours for working.
Answer:
C
Explanation:
A)
B)
C)
D)
320)
320)
Why should caution be exercised when replacing a low-efficiency air filter with a
higher-efficiency air filter?
A)
It is possible for air that is too clean to increase the occupant's sensitivity to allergens.
B)
Air-conditioning coils depend on a certain amount of small particulates to help moisture
precipitate out of the air.
C)
Higher-efficiency filters have a higher pressure drop, which can cause poor airflow.
D)
The lower pressure drop across high-efficiency filters can cause the blower motor to draw
high amps.
Answer:
C
Explanation:
A)
B)
C)
D)
83
321)
321)
How does the technician know which way to install a disposable panel air filter?
A)
The arrow on the side of the filter points in the direction of airflow.
B)
The side of the filter that is reinforced should be installed in the entering airflow.
C)
The arrow on the side of the filter points towards the entering air side.
D)
Most disposable filters can be installed in either direction.
Answer:
A
Explanation:
A)
B)
C)
D)
322)
322)
The effects of noncondensible gases in the refrigeration system are which of the following? You
may select more than one.
A)
Increased high-side pressure
B)
Low-side pressure in a vacuum
C)
Oil dilution
D)
Low capacity
E)
Hot compressor
Answer:
A, D, E
Explanation:
A)
B)
C)
D)
E)
323)
323)
If the compressor oil on a hermetic compressor is acidic, the next step is to change the:
A)
Compressor oil once.
B)
System filter driers repeatedly.
C)
System filter driers once.
D)
Compressor oil repeatedly.
Answer:
B
Explanation:
A)
B)
C)
D)
324)
324)
Before opening the compressor crankcase to take an oil sample, you should:
A)
Increase the crankcase pressure with nitrogen to at least 100 psig.
B)
Position yourself directly in front of the drain port.
C)
Valve off the compressor and recover the refrigerant down to 12 psig.
D)
Get the sample tube ready because the oil comes out very quickly under pressure.
Answer:
C
Explanation:
A)
B)
C)
D)
84
325)
325)
Just before charging the system with clean refrigerant, you should:
A)
Install filter driers.
B)
Evacuate the system.
C)
Recover the refrigerant.
D)
Flush the system.
Answer:
B
Explanation:
A)
B)
C)
D)
326)
326)
What is the difference between a standard liquid line drier and a filter that is designed to be used
following a flush procedure?
A)
Cleanup driers will remove smaller particles but less moisture.
B)
Regular driers are all biflow driers.
C)
Cleanup driers are all biflow driers.
D)
Regular driers will remove smaller particles but not much moisture.
Answer:
A
Explanation:
A)
B)
C)
D)
327)
327)
Why is nitrogen used to purge the system before using the flushing solvent?
A)
The flush is activated by the presence of nitrogen.
B)
Nitrogen is more effective.
C)
Nitrogen will blow open the clogs.
D)
Nitrogen is cheaper.
Answer:
D
Explanation:
A)
B)
C)
D)
328)
328)
The effects of small carbon particles inside the refrigeration system include which of the
following? You may select more than one.
A)
Grounding hermetic compressor terminals
B)
Improving internal compressor lubrication
C)
Restricting metering devices
D)
Making the compressor shell brittle
Answer:
A, C
Explanation:
A)
B)
C)
D)
85
329)
329)
Isolating the break in a circuit by starting at a point where there is correct voltage, and moving
one lead from point to point toward the nonfunctional load is called:
A)
Shotgunning.
B)
Quantitative analysis.
C)
Hopscotching.
D)
Running the rat.
Answer:
C
Explanation:
A)
B)
C)
D)
330)
330)
When an evaporator float switch is used in the drain pan of an air conditioner or heat pump, if the
drain pan fills up, the float will interrupt the low-voltage circuit to:
A)
The gas valve.
B)
The compressor contactor.
C)
The fan relay.
D)
The condensate pump.
Answer:
B
Explanation:
A)
B)
C)
D)
331)
331)
A system that is undercharged will operate with:
A)
A high subcooling and a low superheat.
B)
A low subcooling and a low superheat.
C)
A low subcooling and a high superheat.
D)
A high subcooling and a high superheat.
Answer:
C
Explanation:
A)
B)
C)
D)
332)
332)
An air-conditioning system with a high-side restriction will operate with:
A)
A low suction pressure and a low head pressure.
B)
A low suction pressure and a high head pressure.
C)
A high suction pressure and a high head pressure.
D)
A high suction pressure and a low head pressure.
Answer:
D
Explanation:
A)
B)
C)
D)
86
333)
333)
A problem that can look like low refrigerant charge if a service technician is only looking at
system pressures is:
A)
Low evaporator airflow.
B)
Low condenser airflow.
C)
An overfeeding refrigerant metering device.
D)
High evaporator airflow.
Answer:
A
Explanation:
A)
B)
C)
D)
334)
334)
When correcting the system concern, you must:
A)
Replace the major system components.
B)
Be sure to address the root cause of the concern.
C)
Correct the obvious symptoms first.
D)
Document the correct operation of the system.
Answer:
B
Explanation:
A)
B)
C)
D)
335)
335)
Which of the following condenser types is most efficient?
A)
Cumulative
B)
Evaporative
C)
Water-cooled
D)
Air-cooled
Answer:
B
Explanation:
A)
B)
C)
D)
336)
336)
What visual clues on a system can indicate the presence of a refrigerant leak?
A)
A greenish stain around the area of the leak
B)
A visible cloud of refrigerant in the area of the leak
C)
Refrigerant bubbles forming around the leak
D)
Oil stains around the area of the leak
Answer:
D
Explanation:
A)
B)
C)
D)
87
337)
337)
When replacing or repairing any electrical components, always verify that the:
A)
Power source is disconnected and locked out.
B)
Replacement part is rated for more voltage than the original.
C)
Refrigerant is a non-ozone-depleting chemical.
D)
Voltage is available to the unit.
Answer:
A
Explanation:
A)
B)
C)
D)
338)
338)
The potential relay coil is wired:
A)
In parallel with the run winding.
B)
In series with the run winding.
C)
In parallel with the start winding.
D)
In series with the start winding.
Answer:
C
Explanation:
A)
B)
C)
D)
339)
339)
To manually defrost a frozen evaporator coil, technicians should:
A)
Use a heat gun to accelerate the melting of the ice.
B)
Chip away the ice from the coil using a tool designed for chipping ice.
C)
Spray the ice with liquid refrigerant, which will boil and melt the ice.
D)
Use any available sharp object to chip away ice from the coil.
Answer:
A
Explanation:
A)
B)
C)
D)
340)
340)
A reciprocating compressor with leaking valves will operate with:
A)
A low amp draw, low suction pressure, and low head pressure.
B)
A high amp draw, high suction pressure, and high head pressure.
C)
No amp draw, zero suction pressure, and zero head pressure.
D)
A low amp draw, high suction pressure, and low head pressure.
Answer:
D
Explanation:
A)
B)
C)
D)
88
341)
341)
Before starting a new unit, the technician should:
A)
Check the unit amp draw.
B)
Check the system superheat.
C)
Ohm out all electrical components.
D)
Perform both a mechanical and electrical precheck.
Answer:
D
Explanation:
A)
B)
C)
D)
342)
342)
The maximum safe level to pressurize a system with nitrogen when checking for leaks is:
A)
A pressure equal to the saturation pressure at 150°F for the system refrigerant.
B)
The high-side system test pressure.
C)
The low-side system test pressure.
D)
500 psig.
Answer:
C
Explanation:
A)
B)
C)
D)
343)
343)
When installing a split system, what should be done before opening the installation valves?
A)
Evacuate the lines and coil.
B)
Heat the valve body with a torch to loosen it so that it will turn freely.
C)
Purge the lines and coil with nitrogen to ensure that they are clean.
D)
Add a small quantity of water to prevent the o-rings in the valves from drying out.
Answer:
A
Explanation:
A)
B)
C)
D)
344)
344)
The purpose of purging the lines with nitrogen during brazing is to:
A)
Prevent the formation of copper oxide inside the lines.
B)
Reduce the amount of refrigerant that must be added once the installation is completed.
C)
Pressurize the lines for leak testing.
D)
Increase the temperature of the torch flame and decrease brazing time.
Answer:
A
Explanation:
A)
B)
C)
D)
89
345)
345)
Which refrigerant lines are normally insulated in a typical residential split-system installation?
A)
The liquid line
B)
The condensate line
C)
The discharge line
D)
The suction line
Answer:
D
Explanation:
A)
B)
C)
D)
346)
346)
Key safety aspects that should be checked during a planned maintenance service call for any
combustion appliance include (you may select more than one):
A)
CO levels in flue gas and around unit.
B)
The presence of CO2.
C)
Furnace cabinet temperature.
D)
Combustion air.
E)
Vent system integrity.
Answer:
A, D, E
Explanation:
A)
B)
C)
D)
E)
347)
347)
The most common times to perform a seasonal check on heating equipment are in the:
A)
Spring.
B)
Winter.
C)
Summer.
D)
Fall.
Answer:
D
Explanation:
A)
B)
C)
D)
348)
348)
The most important elements to check for in gas furnaces are adequate combustion air and:
A)
Airflow components.
B)
Refrigerant levels.
C)
Proper venting.
D)
Electrical connections.
Answer:
C
Explanation:
A)
B)
C)
D)
90
349)
349)
A belt that vibrates and jumps around while operating can most likely be corrected by:
A)
Spraying the belt with belt dressing.
B)
Tightening the belt.
C)
Aligning the belt.
D)
Replacing the belt.
Answer:
C
Explanation:
A)
B)
C)
D)
350)
350)
Before starting to change a belt on a belt drive blower, the technician should:
A)
Turn the power to the unit off and lock it out.
B)
Wedge a metal bar between the pulley and the unit housing to prevent it from starting.
C)
Put on heavy work gloves in case the unit is inadvertently started while changing the belt.
D)
Turn the thermostat off and leave instructions not to turn it on.
Answer:
A
Explanation:
A)
B)
C)
D)
351)
351)
Which of the following is an example of baseline condenser data?
A)
Amp draw for the system
B)
Temperature of air in
C)
Suction line temperature
D)
Discharge pressure
Answer:
B
Explanation:
A)
B)
C)
D)
352)
352)
When should a technician record a system's baseline data?
A)
On a new system after it is installed
B)
Whenever the air filter is changed
C)
Whenever refrigerant is added
D)
On an older system that is having problems
Answer:
A
Explanation:
A)
B)
C)
D)
91
353)
353)
Technicians should be cautious when taking an oil sample from a semihermetic compressor
because:
A)
The oil sample must be done with the compressor running.
B)
The compressor crankcase is under pressure.
C)
The oil is highly flammable.
D)
The oil is highly toxic.
Answer:
B
Explanation:
A)
B)
C)
D)
354)
354)
When flushing the system, you should:
A)
Always flush through the accumulator to remove accumulated debris.
B)
Flush through the compressor first.
C)
Flush through the entire system through the service valves.
D)
Disconnect the lines and flush through them separately.
Answer:
D
Explanation:
A)
B)
C)
D)
355)
355)
In an induced-draft gas furnace, the first component to energize on a call for heat is:
A)
The gas valve.
B)
The hot surface igniter.
C)
The induced-draft blower.
D)
The indoor blower.
Answer:
C
Explanation:
A)
B)
C)
D)
356)
356)
The low-pressure switch on a residential split-system condensing unit normally interrupts the
circuit to:
A)
The common terminal of the compressor.
B)
The start terminal of the compressor.
C)
The run terminal of the compressor.
D)
The contactor coil.
Answer:
D
Explanation:
A)
B)
C)
D)
92
357)
357)
A system operating with a low superheat and a low subcooling most likely has:
A)
A refrigerant restriction.
B)
Low condenser airflow.
C)
An overfeeding refrigerant metering device.
D)
Low evaporator airflow.
Answer:
C
Explanation:
A)
B)
C)
D)
358)
358)
The reversing valve on most air-source residential heat pumps is energized:
A)
During the defrost cycle.
B)
During the cooling cycle.
C)
During the cooling and the defrost cycles.
D)
During the heating cycle.
Answer:
C
Explanation:
A)
B)
C)
D)
359)
359)
The current relay coil is wired:
A)
In parallel with the start winding.
B)
In series with the run winding.
C)
In series with the start winding.
D)
In parallel with the run winding.
Answer:
B
Explanation:
A)
B)
C)
D)
360)
360)
On run capacitors, any sign of bulging of its body is a sign of a(n) ________ capacitor.
A)
old
B)
good
C)
bad
D)
charged
Answer:
C
Explanation:
A)
B)
C)
D)
93
361)
361)
Ultrasonic leak detectors detect refrigerant leaks by:
A)
Hearing the high frequency of the escaping gas.
B)
Seeing the change in ultraviolet radiation around the area of the leak.
C)
Seeing the refrigerant by sensing the effect that the leaking refrigerant gas has on sonar.
D)
Seeing the change in infrared radiation around the area of the leak.
Answer:
A
Explanation:
A)
B)
C)
D)
362)
362)
What are the three main circuit characteristics commonly measured to troubleshoot electrical
circuits?
A)
Frequency, current, and impedance
B)
Voltage, current, and resistance
C)
Volts, watts, and impedance
D)
Capacitance, inductance, and resistance
Answer:
B
Explanation:
A)
B)
C)
D)
363)
363)
Which installation phase is performed last?
A)
Start and check
B)
Ductwork installation
C)
Piping installation
D)
Evacuation and charging
Answer:
A
Explanation:
A)
B)
C)
D)
364)
364)
What is the difference between a standard and a code?
A)
Standards are written to be adopted as laws.
B)
Codes often carry the force of law.
C)
Codes and standards are two terms for the same thing.
D)
Codes are a description of best current practices.
Answer:
B
Explanation:
A)
B)
C)
D)
94
365)
365)
The most important consideration when installing a unit with an air-cooled condenser is:
A)
Ensuring adequate airflow.
B)
Making the installation aesthetically pleasing.
C)
Leveling the pad.
D)
Installing the pad foundation below the frost line.
Answer:
A
Explanation:
A)
B)
C)
D)
366)
366)
A common cause of low system superheat is:
A)
Depletion of the superheat coating on the evaporator coil.
B)
Oversized evaporator coils.
C)
Poor airflow across the evaporator.
D)
System undercharged with refrigerant.
Answer:
C
Explanation:
A)
B)
C)
D)
367)
367)
Define planned maintenance.
A)
Performing maintenance and testing based on a regular schedule
B)
Replacing all system components on a rotating basis
C)
Performing maintenance and testing whenever the system quits operating correctly
D)
Monitoring key performance indicators and performing maintenance when these indicators
show a need for maintenance
Answer:
A
Explanation:
A)
B)
C)
D)
368)
368)
How are water pumps in hydronic heating systems checked?
A)
By measuring the pump motor RPM using a digital tachometer
B)
By measuring the impeller RPM using a stroboscope
C)
By measuring the temperature of the pump motor
D)
By measuring the water flow in the system
Answer:
D
Explanation:
A)
B)
C)
D)
95
369)
369)
A safer alternative to debrazing components is to:
A)
Cut them out with a tubing cutter.
B)
Melt through the pipe with a cutting torch.
C)
Cut the components out with a hacksaw.
D)
Pressurize the system with 100 psig of nitrogen before debrazing.
Answer:
A
Explanation:
A)
B)
C)
D)
370)
370)
How does an oil acid test kit indicate the presence of acid?
A)
The test kit produces a strong pungent odor.
B)
The liquid in the sample tube boils.
C)
The word "acidic" appears on the test strip.
D)
By a color change
Answer:
D
Explanation:
A)
B)
C)
D)
371)
371)
When changing a low-voltage transformer, the service technician should:
A)
Check all low-voltage controls for shorts and grounds.
B)
Use a replacement transformer with a higher VA rating to make it last longer.
C)
Temporarily short across the secondary side of the transformer to test its output.
D)
Use a replacement transformer with a higher-voltage primary winding to make it last
longer.
Answer:
A
Explanation:
A)
B)
C)
D)
372)
372)
When searching for a break in a circuit by hopscotching, the technician checks:
A)
The voltage at each switch in the circuit.
B)
The resistance of each switch in the circuit.
C)
The amp draw at each switch in the circuit.
D)
The wattage of each switch in the circuit.
Answer:
A
Explanation:
A)
B)
C)
D)
96
373)
373)
What two readings are needed to calculate the condenser air temperature difference?
A)
Refrigerant temperature into and out of the condenser
B)
Air temperature into and out of the condenser
C)
Water temperature into and air temperature out of the condenser
D)
Air temperature into and water temperature out of the condenser
Answer:
B
Explanation:
A)
B)
C)
D)
374)
374)
Select the possible causes of an underfeeding TEV. You may select more than one.
A)
TEV sensing bulb not making good thermal contact
B)
Restricted inlet screen on TEV
C)
High superheat adjustment
D)
Undersized valve
E)
Restricted filter drier
F)
Low superheat adjustment
G)
Dead thermostatic bulb charge
H)
Oversized TEV
Answer:
B, C, D, E, G
Explanation:
A)
B)
C)
D)
E)
F)
G)
H)
375)
375)
If a technician needs to check the refrigerant pressures on a system with a small charge:
A)
A standard gauge manifold set should be connected to both sides of the system.
B)
Only the low side of the gauge manifold set should be connected.
C)
A short refrigeration gauge should be used.
D)
Only the high side of the gauge manifold set should be connected.
Answer:
C
Explanation:
A)
B)
C)
D)
97
376)
376)
Large pressurized cylinders on air-conditioning systems that hold more than 15 psig internal
pressure must be rated by:
A)
The American Society of Heating, Refrigeration, and Air Conditioning Engineers, ASHRAE.
B)
The Department of Transportation, DOT.
C)
The Environmental Protection Agency, EPA.
D)
The American Society of Mechanical Engineers, ASME.
Answer:
D
Explanation:
A)
B)
C)
D)
377)
377)
Select the code requirements when a unit is located in a crawl space. You may select more than
one.
A)
A light switch by the access door
B)
An adjustable air register by the equipment for the technician
C)
A 30-in-deep service area in front of the service panel
D)
A light near the unit
E)
A 24-ft-wide plywood platform from the access to the unit
F)
A 22" × 30' access door
G)
A maximum of 20 ft from the access to the unit
Answer:
A, C, D, F, G
Explanation:
A)
B)
C)
D)
E)
F)
G)
378)
378)
During an operational check of an air-conditioning system, you should check the:
A)
Temperature drop across the condenser.
B)
Temperature rise across the evaporator.
C)
Oil on the lines or pipe insulation.
D)
Voltage drop on the power wire to the unit.
Answer:
D
Explanation:
A)
B)
C)
D)
98
379)
379)
How is a temperature-pressure relief valve on a hot-water boiler tested?
A)
Pressurize the boiler with nitrogen until the pressure relief valve opens.
B)
Jump the high limit and operate the burners until the pressure relief valve opens.
C)
Pull the lever and look for water at outlet of discharge pipe.
D)
Pressure relief valves are optional, so testing is not required.
Answer:
C
Explanation:
A)
B)
C)
D)
380)
380)
A system operating with a high superheat and a high subcooling most likely has:
A)
Low evaporator airflow.
B)
An overfeeding refrigerant metering device.
C)
A refrigerant restriction.
D)
Low condenser airflow.
Answer:
C
Explanation:
A)
B)
C)
D)
381)
381)
What should you do to isolate the root cause of the malfunction?
A)
Replace all the faulty components.
B)
Perform tests to isolate the cause.
C)
Inspect each component of the system.
D)
Collect any operational data.
Answer:
B
Explanation:
A)
B)
C)
D)
382)
382)
How does accumulated dirt on the condenser coil affect system operation?
A)
Condenser pressure drops but temperature rises.
B)
Condenser temperature drops but pressure rises.
C)
Raises the condenser pressure and temperature
D)
Condenser pressure and temperature drop.
Answer:
C
Explanation:
A)
B)
C)
D)
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