WorksheetsBỘ CÂU HỎI AVCN
Total questions: 100
Worksheet time: 50mins
In what unit are the cooling capacity measured in refrigeration systems?
kJ
kW
kJ/kg
kW.h
Which refrigerant is used most frequently in large industrial plants?
Ammonia
Sulfur Dioxide
Calcium Chloride
Carbon Dioxide
What does HVAC stand for?
Handling, Ventilation, Air Conditioning
Heating, Ventilation, Air conditioning
Heating, Ventilation, Alternating current
Household, Ventilation, Air conditioning
What is not undesirable effect on the refrigeration system of the air purging?
Pressure in the system rises
Operating current rises
Cooling efficiency rises
Water may lead to corrosion of parts in the refrigeration system
In the room air conditioner installation manual, what is the pipe size?
The diameter of the copper pipe
The length of the copper pipe
The thickness of the copper pipe
None of these
Both temperature and ___________ affect the comfort of the human body.
Atmosphere
Altitude
Attitude
Humidity
What is the unit of power?
Resistance
Amperage
Voltage
Wattage
Which of the following is not a primary function of an HVAC system?
Heating
Cooling
Lighting
Ventilation
What is the purpose of an air filter in an HVAC system?
To regulate temperature
To remove dust and particles from the air
To generate airflow
To control humidity levels
What safety precautions should be taken when working with ammonia refrigeration systems?
Use of personal protective equipment (PPE)
Regular maintenance and inspections
Proper ventilation in the equipment room
All of these
What is the role of the thermostat in an air conditioning system?
To regulate airflow
To filter the air
To control temperature settings
To increase humidity levels
What is the primary function of a water chiller system?
To heat water
To purify water
To cool water
To pressurize water
How does a VRV system handle varying loads in different zones?
By operating at a fixed capacity
By adjusting the refrigerant flow rate
By relying on separate HVAC systems for each zone
By using a single ductwork system for the entire building
How does an air-cooled water chiller system typically reject heat from the condenser?
By releasing it to the atmosphere
By circulating it through the building
By using it for cooling purposes
. By absorbing it into the refrigerant
What is the purpose of the drainage system in a split AC installation?
To remove condensation water from the indoor unit
To supply water to the outdoor unit for cooling
To filter the refrigerant
To cool down the compressor
Which statement is the best description about hand tools?
Hand tools are the most effective and efficient way to do many jobs
A hand tool is any tool operated by power to do work
Using the right tool in the wrong way is also safe
Hand tools are used to replace large machine to do work
_______ is used to create smooth edges or create a new shape or profile
Hammer
Screwdriver
Combination wrench
File
A _______ is a relatively simple tool to provide accurate and consistent bends on a variety of tubes including copper tubes, steel tubes and aluminum based tubes:
Tube bender
Tube cutter
Deburring tool
Swaging tool
Which hand tool used for connecting two pieces of copper tube without welding?
Hammer
Torque wrench
Combination pliers
Chisel
Which is not a hand tool used for installing a room air conditioner?
Hammer
Screwdriver
Shovel
Electric drill
___________ is used to measure the distance
Spirit level
Tape measure
Spanner
Screwdriver
Which hand tools is used to fix a mounting plate of an indoor unit?
Spirit leveller
Measuring tape
Drill
All of these
The refrigerant leakage is detected by?
Refrigerant – leak detector
AC clamp on ammeter
Volt-Ohm miliammeter
None of these
__________ is used to remove burrs from the inside and outside of the copper tube
Refrigerant - leak detector
Inner – outer reamer
Swaging tool
Copper tube bender
Which equipment used to evacuate a refrigeration system?
Refrigerant – leak detector
Vacuum pump
Manifold gauges
Electronic scale
How often should air filters typically be replaced in an air conditioning system?
Every 3 months
Every 6 months
Every year
Every 2 years
What is the purpose of regular filter replacement in an air conditioning system?
To improve indoor air quality
To increase energy consumption
To reduce airflow
To decrease cooling efficiency
Which of the following factors should be avoided when selecting the location for indoor unit installation?
All of these
Near direct sunlight exposure
Near heat sources such as stoves or ovens
Near doors or windows
Why is it important to ensure proper airflow around the outdoor unit during installation?
To avoid overheating and improve efficiency
To prevent water damage
To increase energy consumption
To regulate humidity levels
A _______ is used to grip and turn objects
Wrench
File
Hacksaw
Electric Drill
_______ is used to bang in nails or remove nails with the head / claw ends
Hammer
Tape measure
Spirit leveller
Spanner
What is the function of flaring tool set?
It is used to widen the end of the copper tube to connect with another copper tube by welding
It is used to widen the end of the copper tube to connect with another copper tube or fittings without welding
It is used to bend copper tube and form various angles and curves
None of these
The oil separator collects ___________ oil that escapes with the compressor-discharge gas.
Engine
Lubricating
Motor
Condenser
The purpose of the condenser in a refrigeration system is:
To cool hot refrigerant vapor
To dehumidify refrigerant vapor
To dry refrigerant
To condense the cooled refrigerant
Condensers are heat ___________ designed to condense the high-pressure, high-temperature refrigerant discharged by the compressor.
Absorbers
Spreaders
Collectors
Exchangers
What is the best description about a refrigerant?
Refrigerant is the fluid used for heat transfer in a refrigeration system
Refrigerant is the fluid used for heat transfer in a refrigeration system
Refrigerant should have high boiling point and high freezing point
Refrigerant should be flammable, explosive, toxic and corrosive
What is the purpose of stop valve in a refrigeration system?
Shut off the flow of substances
Maintain the pressure difference between evaporator and condenser
Compress the refrigerant to a high pressure
Exchange heat in a refrigeration system
Which is the best statement about evaporator
Evaporator is a heat exchanger used to turn state from gaseous to liquid refrigerant
Evaporator is a heat exchanger used to heat refrigerant from low temperature to high temperature
Evaporator is a heat exchanger used to maintain the pressure difference
Evaporator is a heat exchanger used to turn state from liquid to gaseous refrigerant
Which is the best statement about compressor
Compressor is considered as the heart of a refrigeration system
Compressor is also a heat exchanger
Compressor is used to work with both gaseous and liquid refrigerant
All of these
Which compressor type uses pistons to compress the gas?
Scroll
Reciprocating
Rotary
Screw
_______ is used in a refrigeration system to lubricate the compressor and keep the refrigeration unit running smoothly
Oil
Refrigerant
Water
All of these
What is the emergency button used for?
It is used in case of emergency shutdown
It is used in case of normal shutdown
It is used in case of emergency operation
It is used in case of normal operation
What is kind of gas used to do a leak test?
Oxygen
Nitrogen
Sulfur dioxide
All of these
Which of the following is not a desirable property of a refrigerant?
Low boiling point
Good electrical conductor
Non-flammable
Non – corrosive
Arrange the following steps to have a correct flaring work procedure?
1- Check
2- Putting nut on
3- Burrs removal
4- Cutting tubes
5- Flaring work
1-4-3-2-5
4-3-2-5-1
1-4-2-3-5
4-2-3-5-1
What is not a kind of expansion device?
Capillary tube
Thermostatic expansion valve
Hand expansion valve
Thermostat
In a water chiller system, what is the purpose of the evaporator?
To compress the refrigerant
To release heat to the surroundings
To transfer heat from the water to the refrigerant
To regulate the flow of refrigerant
Which types of heat are considered for occupants’ heat gain in AC space?
Radiant and latent heat
Sensible and latent heat
Sensible and radiant heat
Specific and sensible heat
Which instrument measures the humidity of air?
Barometer
Manometer
Hygrometer
Hydrometer
Which device controls the air flow in ducting system?
Grille
Damper
Register
Diffuser
How many parameters are needed to locate all properties of moist air in psychrometric chart?
One
Two
Four
Three
The component used for reducing the size of the duct is _______________
Reducer
Pipe
Register
Damper
AHU stands for ____________
Air Handling Unit
Air Heating Unit
Air Humidifying Unit
None of these
Pressure drop in ducts take place because of ______________________
Duct Friction
Change of Direction
Change of Velocity
All of these
Which of the following device is also known as throttling device?
Capillary tube
Drier
Receiver
None of these
In vapour compression refrigeration cycle, the condition of refrigerant is dry saturated vapour.......
Before entering the expansion valve
Before entering the compressor
After passing through the condenser
Before passing through the condenser
In vapour compression refrigeration cycle, the condition of refrigerant is saturated liquid.......
Before entering the expansion valve
Before entering the compressor
After passing through the condenser
Before passing through the condenser
What is the input port of a compressor called?
Suction
Housing
Discharge
None of these
What is the output port of a compressor called?
Suction
Housing
Discharge
None of these
Which refrigerant is used with VRV air conditioning system?
R 11
R 12
R 502
R 410A
Where does the lowest temperature occur in a vapor compression cycle?
Condenser
Evaporator
Compressor
Expansion valve
The vapor pressure of refrigerant should be
Higher than atmospheric pressure
Lower than atmospheric pressure
Equal to atmospheric pressure
None of these
What is the composition of oxygen in atmospheric air
11%
21%
31%
41%
Which safety control stops the compressor motor if there is leakage of refrigerant?
LP cut out
HP cut out
Thermostat
Oil pressure cut out
In a refrigeration system, the expansion device is connected between the
Compressor and Condenser
Compressor and Oil separator
Condenser and Evaporator
Condenser and Suction Accumulator
Moisture should be removed from refrigerants to avoid
Freezing at the expansion valve
Restriction to refrigerant flow
Corrosion of the system
All of these
During a refrigeration cycle, heat is rejected by the refrigerant in a
Compressor
Condenser
Evaporator
Expansion valve
During a refrigeration cycle, heat is absorbed by the refrigerant in a
Compressor
Condenser
Evaporator
Expansion valve
The undesirable property of a refrigerant is
Non-toxic
Non-flammable
Non-explosive
High boiling point
Air conditioning means
Cooling
Heating
Dehumidifying
All of these
During sensible heating of air, _________ decreases.
Wet bulb temperature
Relative humidity
Dry bulb temperature
Specific humidity
An evaporator is also known as
Freezing coil
Cooling coil
Chilling coil
All of these
What is the recommended location for installing the outdoor unit of a split AC?
In a closed space to reduce noise
Directly above the indoor unit
In a well-ventilated area, preferably on the shady side of the building
Next to heating equipment for operational efficiency
What is a common mistake to avoid when installing a room air conditioner?
Installing the unit in direct sunlight
Choosing a unit with a BTU rating appropriate for the room size
Ensuring there is adequate support for the unit
Sealing gaps around the unit
What is the first step of RAC installation?
Select the best location for indoor unit and outdoor unit installations
Measure the copper pipe length
Flare the pipe ends
Remove burrs of copper pipe
What is the purpose of the overload relay in the electrical cabinet of a refrigeration system?
To regulate the flow of refrigerant
To control the temperature of the refrigerant
To protect the equipment from overheating
To provide backup power during electrical failures
What type of electrical component is commonly used to protect the circuit from overcurrent in a refrigeration system?
Contactor
Relay
Fuse
Transformer
What is the primary function of the electrical cabinet in a refrigeration system?
To store refrigerants
To house electrical components and controls
To regulate the flow of refrigerant
To control the temperature of the refrigerant
What is the function of a sight glass in a refrigeration system?
To indicate the level of refrigerant in the system
To measure the pressure of the refrigerant
To detect leaks in the system
To regulate the flow of refrigerant
Which instrument is used to measure the flow rate of refrigerant in a refrigeration system?
Thermocouple
Flowmeter
Hygrometer
Leak detector
Which of the following measurements can be obtained using a thermometer in a refrigeration system?
Voltage
Pressure
Humidity
Temperature
What is the primary function of a high-pressure switch in a refrigeration system?
To regulate the flow of refrigerant
To protect the compressor from excessive pressure
To control the temperature of the refrigerant
To monitor the electrical current
What is the primary function of a low-pressure switch in a refrigeration system?
To regulate the flow of refrigerant
To protect the compressor from under acceptable pressure
To control the temperature of the refrigerant
To monitor the electrical current
What is the purpose of duct insulation in HVAC systems?
To regulate airflow
To reduce noise
To prevent condensation and energy loss
To control humidity levels
What is the primary function of air ducts in an HVAC system?
To generate cool air
To circulate refrigerant
To distribute conditioned air to different spaces
To regulate the flow of electricity
Which component of a local air conditioning system is responsible for removing heat from the indoor air?
Compressor
Condenser
Evaporator
Expansion valve
What is the primary purpose of a local air conditioning system?
To cool an entire building
To cool a specific area or room
To cool outdoor spaces
To cool industrial machinery
. What is the primary reason for the phase-out of hydrochlorofluorocarbons (HCFCs) like R-22?
High cost
Low efficiency
Environmental concerns about ozone depletion
Health risks to users
Which of the following is a common property desired in refrigerants?
High flammability
Low toxicity
High global warming potential (GWP)
High ozone depletion potential (ODP)
What is the primary function of a refrigerant in a cooling system?
To generate heat
To regulate airflow
To absorb and release heat
To circulate water
Which tool is used to crimp or secure electrical connectors in air conditioning wiring?
Torque wrench
Stripping pliers
Crimping pliers
Multimeter
What is the purpose of a fin comb in air conditioning maintenance?
To measure airflow
To straighten bent fins on heat exchanger coils
To measure refrigerant pressure
To remove debris from ducts
What is the purpose of a multimeter in air conditioning repair?
To measure temperature
To test electrical circuits for continuity and voltage
To tighten or loosen screws
To check refrigerant levels
Which tool is essential for accurately measuring refrigerant pressures in an air conditioning system?
Pressure gauge
Screwdriver
Pipe wrench
Tape measure
What is the purpose of an adjustable wrench in an air conditioning system?
To cut wires
To measure temperature
To tighten or loosen nuts and bolts
To measure pressure
What effect does dirty evaporator coils have on the cooling efficiency of an air conditioning system?
Increased airflow
Improved heat transfer
Reduced cooling capacity
Decreased energy consumption
How can proper maintenance contribute to improving the cooling efficiency of an air conditioning system?
By increasing airflow restriction
By reducing the insulation
By minimizing airflow
By cleaning coils and replacing filters regularly
What is the purpose of inspecting and cleaning the condensate drain during air conditioning maintenance?
To increase energy consumption
To improve airflow
To prevent water damage and mold growth
To decrease cooling efficiency
What is the purpose of lubricating moving parts in an air conditioning system?
To increase energy consumption
To decrease cooling efficiency
To reduce friction and wear
To improve airflow
What is the purpose of inspecting and cleaning evaporator coils during air conditioning maintenance?
To increase energy consumption
To improve airflow
To decrease cooling efficiency
To reduce refrigerant levels
