40+ AC Technician Interview Questions and Answers

The answer to the questions related to AC Technician interview.

• There are four refrigeration cycles: vapor compression, absorption, steam jet, and air cycle.

• There are various types of compressors used in AC systems, such as reciprocating, rotary, scroll, and centrifugal compressors.

• Compressors can have different types of connections, including sweat connections, flare connections, and threaded connections.

• TXV (Thermostatic Expansion Valve) and EXV (Electronic Expansion Valve) ...read more

The refrigerant used in a refrigeration system depends on the type of system and its application.

• Common refrigerants include R-22, R-134a, and R-410A.

• Refrigerants are chosen based on their thermodynamic properties, safety, and environmental impact.

• Newer systems often use more environmentally friendly refrigerants like R-410A.

• Refrigerants must be handled and disposed of properly to prevent harm to people and the environment.

Primary, secondary, condenser pump and AHU are components of HVAC system that work together to regulate temperature and air flow.

• Primary pump circulates chilled water from chiller to AHU

• Secondary pump circulates hot water from boiler to AHU

• Condenser pump circulates water from chiller to cooling tower

• AHU (Air Handling Unit) conditions and circulates air throughout the building

The number of sensors in an inverter AC can vary depending on the model and brand.

• The number of sensors in an inverter AC typically ranges from 3 to 5.

• Sensors in an inverter AC can include temperature sensors, humidity sensors, and pressure sensors.

• Some high-end inverter AC models may have additional sensors for more precise control and energy efficiency.

Safety precautions in a refrigeration system include proper ventilation, regular maintenance, and following safety guidelines.

• Ensure proper ventilation to prevent the buildup of harmful gases

• Regularly inspect and maintain the system to prevent leaks and malfunctions

• Follow safety guidelines and use personal protective equipment (PPE) when working with refrigerants

• Handle refrigerants properly and dispose of them according to regulations

• Be aware of electrical hazards and take ne...read more

Neutral wire carries current back to the source and is at 0 volts, while earthing wire is used for safety and is at 0 volts under normal conditions.

• Neutral wire carries current back to the source and is at 0 volts.

• Earthing wire is used for safety and is at 0 volts under normal conditions.

• Voltage on neutral and earthing wires should ideally be 0 volts to ensure proper functioning and safety of electrical systems.

Yes, I am capable of repairing PCB boards of electronic components.

• I have experience in troubleshooting and repairing PCB boards.

• I am familiar with using multimeters, oscilloscopes, and other diagnostic tools.

• I have knowledge of soldering and desoldering techniques.

• I am able to read and interpret schematics and datasheets.

• I have repaired PCB boards for various electronic devices such as air conditioners, refrigerators, and televisions.

Qualifications for railway AC technicians typically include a high school diploma or equivalent, completion of a vocational training program, and relevant certifications.

• High school diploma or equivalent is usually required

• Completion of a vocational training program in HVAC or related field is necessary

• Relevant certifications such as EPA 608 certification may be required

• Experience working with HVAC systems, especially in railway settings, is beneficial

The weekly off will be decided based on the company's policy and the employee's work schedule.

• The weekly off will be communicated during the onboarding process.

• It may vary based on the project requirements and workload.

• The company may follow a fixed weekly off schedule or a rotational schedule.

• The employee can discuss their preferences with their supervisor.

• The weekly off may also depend on the client's requirements.

• The company may also have provisions for emergency work on w...read more

HVAC stands for Heating, Ventilation, and Air Conditioning. It refers to the technology of indoor environmental comfort.

• Heating: The process of raising the temperature of an enclosed space to provide comfort.

• Ventilation: The exchange of indoor and outdoor air to maintain air quality.

• Air Conditioning: The process of controlling the temperature, humidity, and cleanliness of air within a space.

• HVAC systems are commonly used in residential, commercial, and industrial buildings.

• Pr...read more

The question is about maintaining -18 temperature while charging gas in Kc compressor.

• Use a refrigerant with a boiling point lower than -18°C

• Ensure proper insulation of the refrigeration system

• Check for any leaks in the system

• Adjust the expansion valve to maintain the desired temperature

• Regularly clean the condenser and evaporator coils

There are two main types of compressors - reciprocating and rotary. Freon gases are a group of refrigerants used in HVAC systems.

• Reciprocating compressors use pistons to compress refrigerant gas, while rotary compressors use rotating mechanisms.

• Common freon gases include R-22 (chlorodifluoromethane) and R-410A (hydrofluorocarbon).

• Freon gases are used as refrigerants in air conditioning systems to absorb and release heat.

• Newer HVAC systems are transitioning to more environment...read more

Testing of air conditioner and wifi module involves checking their functionality and connectivity.

• For air conditioner testing, check the temperature, airflow, and refrigerant levels.

• For wifi module testing, check the signal strength, connectivity, and speed.

• Use specialized tools like a thermometer, pressure gauge, and network analyzer for accurate testing.

• Perform regular maintenance and updates to ensure optimal performance.

• Test the integration of the wifi module with the air...read more

I'm sorry, but I cannot answer this question as it is unclear what is being asked.

• Please provide more context or clarify the question.

• It is unclear what is meant by 'benefit in voltas.'

• Without more information, I cannot provide a meaningful answer.

An air-conditioning example is a system that cools and dehumidifies air in a building or vehicle.

• Air conditioning systems use refrigerants to cool the air

• They remove heat and moisture from the air to create a comfortable indoor environment

• Examples include central air conditioning units, window units, and portable air conditioners

The resistance of a circuit is measured in ohms.

• Resistance is measured in ohms (Ω)

• Ohm's Law states that V = I * R, where V is voltage, I is current, and R is resistance

• Higher resistance means less current flow in a circuit

• Resistance can be calculated using the formula R = V / I

The sensor voltage can vary depending on the type of sensor and its application.

• Sensor voltage can range from millivolts to volts depending on the sensor type.

• It is important to refer to the sensor datasheet for specific voltage requirements.

• Some sensors may require a specific voltage input for accurate readings.

• Sensor voltage may also be influenced by external factors such as temperature and humidity.

The discharge pressure of R410a refrigerant varies depending on the operating conditions.

• The discharge pressure can range from 300 to 500 psi depending on the ambient temperature and load conditions.

• Higher discharge pressure indicates a higher load on the system.

• Proper charging and airflow are important to maintain the correct discharge pressure.

• A pressure gauge is used to measure the discharge pressure.

• The discharge pressure should be checked regularly to ensure the system i...read more

Phase reversal can be identified by checking the rotation direction of the motor or using a phase rotation meter.

• Check the rotation direction of the motor - if it is rotating in the opposite direction, it indicates a phase reversal

• Use a phase rotation meter to determine the sequence of the phases and identify any phase reversals

• Consult the wiring diagram of the system to ensure correct phase connections

The gas mostly used in air conditioning is refrigerant.

• Refrigerant is the gas used in air conditioning systems to absorb and release heat.

• Common refrigerants used include R-410A, R-22, and R-134a.

• Refrigerants undergo phase changes from liquid to gas and back to liquid to cool the air.

Common refrigerant gases used in refrigerators are R-134a and R-600a.

• R-134a is a hydrofluorocarbon (HFC) refrigerant with a global warming potential of 1430.

• R-600a is a hydrocarbon refrigerant with a global warming potential of 3.

The chemical name for water cooled chiller is Ethylene Glycol.

• Ethylene Glycol is a colorless, odorless, sweet-tasting, viscous liquid.

• It is used as a coolant in water-cooled chiller systems.

• It prevents freezing and corrosion in the system.

• It is also used in antifreeze and de-icing solutions for aircrafts.

• It is toxic if ingested and can cause serious health problems.

• Proper handling and disposal is necessary to prevent harm to humans and the environment.

Non-inverter AC compressor not working

• Check if the power supply to the AC unit is functioning properly

• Inspect the compressor for any visible damage or signs of wear

• Ensure that the thermostat is set correctly and functioning

• Check if the condenser coils are clean and not blocked by debris

• Verify if the capacitor is working and providing the necessary start-up power

• Test the compressor motor for continuity and proper electrical connections

Suction pressure of 110-120 psi is within the normal range for an air conditioner.

• Suction pressure is a measure of the refrigerant's pressure as it enters the compressor.

• Normal suction pressure for an air conditioner typically ranges between 70-120 psi.

• Suction pressure outside this range may indicate a problem with the system.

• Examples of issues related to suction pressure include low refrigerant charge or a faulty compressor.

The main part of refrigeration is the refrigeration cycle.

• The refrigeration cycle is a continuous process that removes heat from a space and transfers it to the surroundings.

• It consists of four main components: compressor, condenser, expansion valve, and evaporator.

• The compressor compresses the refrigerant gas, raising its temperature and pressure.

• The high-pressure gas then flows to the condenser, where it releases heat and condenses into a high-pressure liquid.

• The liquid ref...read more

Air conditioner is a device used to cool and dehumidify indoor air for comfort.

• AC stands for Air Conditioner

• AC units work by removing heat and moisture from the air

• Common types of AC units include window units, split systems, and central air conditioning

• Regular maintenance of AC units is important for optimal performance

Continuity can be checked by testing the flow of electrical current through a circuit.

• Use a multimeter to test for continuity by setting it to the continuity or resistance mode.

• Place the multimeter probes at each end of the circuit or component being tested.

• If the multimeter beeps or shows a low resistance reading, there is continuity.

• If there is no beep or a high resistance reading, there is no continuity.

The type of compressor can vary depending on the specific AC unit, but common types include reciprocating, rotary, and scroll compressors.

• Common types of compressors include reciprocating, rotary, and scroll compressors

• Reciprocating compressors use pistons to compress refrigerant gas

• Rotary compressors use rotating vanes to compress refrigerant gas

• Scroll compressors use spiral-shaped scrolls to compress refrigerant gas

To find out tangents, use trigonometric functions like tan() or calculate the ratio of opposite side to adjacent side in a right triangle.

• Use the tan() function in a calculator or programming language to find the tangent of an angle.

• In a right triangle, the tangent of an angle can be calculated by dividing the length of the side opposite the angle by the length of the side adjacent to the angle.

• Remember that the tangent function is defined as the ratio of the opposite side to...read more

A 12 time blinking green light typically indicates a communication error with the HVAC system.

• Check the user manual for the specific HVAC system to interpret the blinking light codes.

• Reset the system by turning off the power for a few minutes and then turning it back on.

• If the issue persists, contact a professional AC technician for further diagnosis and repair.

Cooling capacity per hour is the amount of heat energy that can be removed from a space in one hour.

• Cooling capacity is measured in BTUs (British Thermal Units) or tons

• The size of the space being cooled and the desired temperature affect the cooling capacity needed

• For example, a 1-ton AC unit can remove 12,000 BTUs of heat per hour

• Calculating cooling capacity requires knowledge of the specific heat of the material being cooled

BTU stands for British Thermal Unit, CAV stands for Constant Air Volume, and AHU stands for Air Handling Unit.

• BTU is a unit of measurement used to quantify the amount of heat energy needed to raise the temperature of one pound of water by one degree Fahrenheit.

• CAV refers to a type of HVAC system where the airflow remains constant while the temperature varies.

• AHU is a device used to regulate and circulate air as part of a heating, ventilating, and air conditioning system.

VCRS cycling is the process of a variable capacity refrigeration system adjusting its cooling output based on demand.

• VCRS cycling is used in HVAC systems to improve energy efficiency and reduce operating costs.

• The system adjusts the compressor speed to match the cooling demand, rather than running at full capacity all the time.

• This results in more precise temperature control and less wear and tear on the system.

• For example, if a room needs less cooling during the day when the...read more

AC purpose is to cool and dehumidify indoor air, while electrical purpose is to power the AC unit.

• AC purpose is to regulate temperature and humidity in indoor spaces.

• Electrical purpose is to provide the necessary power for the AC unit to function.

• ACs use refrigeration cycles to cool the air and remove moisture.

• Electrical components in an AC unit include compressors, fans, and motors.

• ACs are commonly used in homes, offices, and vehicles to provide comfort.

• Electrical wiring and...read more

The fan motor checking process involves inspecting the motor for any issues that may affect its performance.

• Check for any unusual noises coming from the motor

• Inspect the motor for any signs of overheating or burning

• Test the motor's electrical connections for proper voltage and current

• Check the motor's bearings for any signs of wear or damage

A chiller is a machine that removes heat from a liquid via a vapor-compression or absorption refrigeration cycle.

• A chiller is used to cool down a liquid or air in various applications.

• It works by removing heat from the liquid or air through a refrigeration cycle.

• Chillers are commonly used in air conditioning systems, industrial processes, and medical equipment.

• They can be water-cooled or air-cooled, depending on the application.

• Examples of chillers include air conditioners, r...read more

VRF stands for Variable Refrigerant Flow. It is a HVAC technology that allows for individual control of temperature in different zones.

• VRF is a type of air conditioning system that uses refrigerant as the cooling and heating medium.

• It allows for simultaneous heating and cooling in different areas of a building.

• VRF systems can adjust the amount of refrigerant flowing to each indoor unit based on the cooling or heating demand.

• This technology is energy-efficient and provides pre...read more

Yes, I have experience with all aspects of AC installation and repair.

• Experienced in installing various types of AC units

• Skilled in diagnosing and repairing AC issues

• Knowledgeable about HVAC systems and components

• Familiar with safety protocols and regulations for AC work

Heating, Ventilation, and Air Conditioning

• HVAC stands for Heating, Ventilation, and Air Conditioning

• It is a system used for controlling the temperature, humidity, and air quality in buildings

• HVAC technicians are responsible for installing, maintaining, and repairing HVAC systems