70+ Hvac Technician Interview Questions and Answers

There are several types of compressors used in HVAC systems worldwide.

• Reciprocating compressors

• Rotary compressors

• Scroll compressors

• Centrifugal compressors

• Screw compressors

• Axial compressors

• Diaphragm compressors

• Vane compressors

There are five types of compressors: reciprocating, centrifugal, rotary, screw, and scroll.

• Reciprocating compressors use pistons to compress air.

• Centrifugal compressors use a rotating impeller to create centrifugal force.

• Rotary compressors use rotating screws or vanes to compress air.

• Screw compressors use two interlocking screws to compress air.

• Scroll compressors use two spiral-shaped scrolls to compress air.

There are two types of compressors: positive displacement and dynamic. Electrical troubleshooting and wiring are also important skills for HVAC technicians, with a focus on star delta wiring. Knowledge of chiller and DX units is also necessary.

• Two types of compressors: positive displacement and dynamic

• Electrical troubleshooting and wiring skills are important

• Focus on star delta wiring

• Knowledge of chiller and DX units is necessary

There are five types of compressors: Reciprocating, Centrifugal, Rotary, Screw, and Scroll.

• Reciprocating compressors use pistons to compress air.

• Centrifugal compressors use a rotating impeller to create centrifugal force.

• Rotary compressors use rotating screws or vanes to compress air.

• Screw compressors use two interlocking screws to compress air.

• Scroll compressors use two spiral-shaped scrolls to compress air.

HVAC stands for Heating, Ventilation, and Air Conditioning. It refers to the technology and systems used to control indoor environmental conditions.

• HVAC is an acronym for Heating, Ventilation, and Air Conditioning.

• It encompasses the technology and systems used to control indoor temperature, humidity, and air quality.

• Heating systems provide warmth, ventilation systems circulate and exchange air, and air conditioning systems cool and dehumidify the air.

• HVAC technicians install,...read more

Breakdowns in HVAC systems can range from minor issues to major malfunctions. Quick reaction is necessary to prevent further damage.

• Common breakdowns include faulty thermostats, clogged filters, and refrigerant leaks

• React by shutting off the system and contacting a professional technician

• Regular maintenance can prevent breakdowns and extend the lifespan of the system

The expansion valve operates on two pressures and temperatures - high and low.

• The expansion valve is responsible for regulating the flow of refrigerant into the evaporator.

• It operates on two pressures and temperatures - high and low.

• The high pressure and temperature are on the inlet side of the valve, while the low pressure and temperature are on the outlet side.

• The valve works by sensing the temperature and pressure of the refrigerant and adjusting the flow accordingly.

• Examp...read more

Identifying maintenance risks, diagnosing faults, and repairing HVAC systems.

• Perform regular inspections to identify potential maintenance risks on HVAC equipment.

• Use diagnostic tools and techniques to identify electrical and mechanical faults in HVAC systems.

• Clean and adjust HVAC components to ensure optimal performance.

• Repair or replace faulty parts to restore functionality.

• Examples: Identifying a refrigerant leak, diagnosing a faulty thermostat, cleaning clogged air filter...read more

District cooling systems are efficient and cost-effective for cooling large areas. The main part of ETS is the thermal storage tank.

• District cooling systems are centralized systems that use chilled water to cool multiple buildings in a given area.

• They are more energy-efficient and cost-effective than individual cooling systems for each building.

• The main part of ETS (Energy Transfer Station) is the thermal storage tank, which stores chilled water for distribution to the buildi...read more

HVAC stands for Heating, Ventilation, and Air Conditioning. It is a system used to control the temperature, humidity, and air quality in buildings.

• HVAC is an acronym for Heating, Ventilation, and Air Conditioning.

• It is a system that regulates the temperature, humidity, and air quality in buildings.

• Heating is provided through furnaces, boilers, or heat pumps.

• Ventilation involves the exchange of indoor and outdoor air to maintain fresh air supply.

• Air conditioning cools and dehu...read more

HVAC has high pressure from the compressor to the condenser.

• High pressure is generated by the compressor and sent to the condenser.

• The pressure is typically around 300-400 PSI.

• The refrigerant then flows through the expansion valve and into the evaporator where it becomes low pressure.

• The low pressure refrigerant then returns to the compressor to start the cycle again.

The +,- temperature is the difference between the actual temperature and the desired temperature. HVAC technicians work to adjust the temperature accordingly.

• The +,- temperature is also known as the temperature differential.

• It is calculated by subtracting the desired temperature from the actual temperature.

• HVAC technicians use this measurement to adjust the heating or cooling system to achieve the desired temperature.

• For example, if the desired temperature is 72°F and the act...read more

HVAC stands for Heating, Ventilation, and Air Conditioning.

• HVAC is an acronym for Heating, Ventilation, and Air Conditioning.

• It refers to the technology used for indoor environmental comfort.

• Heating systems, ventilation systems, and air conditioning systems are all part of HVAC.

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

• Examples of HVAC equipment include furnaces, air conditioners, heat pumps, and ventilation fans.

HVAC stands for Heating, Ventilation, and Air Conditioning.

• HVAC is an acronym for Heating, Ventilation, and Air Conditioning.

• It refers to the technology used for indoor environmental comfort.

• HVAC systems are responsible for heating, cooling, and controlling the air quality in buildings.

• Examples of HVAC equipment include furnaces, air conditioners, heat pumps, and ventilation systems.

CHW IN OUT temp difference and adaptive control alarm troubleshooting for HVAC technician.

• CHW IN OUT temp difference is the temperature difference between the chilled water entering and leaving the HVAC system.

• Adaptive control is a system that adjusts the HVAC system's output based on the current conditions.

• Alarm troubleshooting involves identifying and resolving any issues with the HVAC system's alarms.

• Examples of alarm troubleshooting include checking for faulty sensors or ...read more

Copper pipes are commonly used for HVAC systems in hospitals.

• Copper pipes are preferred due to their durability and resistance to corrosion.

• They are used for both hot and cold water supply, as well as for refrigerant lines.

• Other materials such as PVC and PEX may also be used for certain applications.

• The specific type of pipe used may vary depending on the hospital's needs and budget.

• Proper installation and maintenance of pipes is crucial to ensure safe and efficient operation...read more

I would communicate with the client promptly, provide updates on the repair progress, offer alternative solutions if needed, and ensure their satisfaction.

• Communicate with the client promptly to inform them about the breakdown

• Provide regular updates on the repair progress to keep the client informed

• Offer alternative solutions or temporary fixes if the repair will take longer

• Ensure the client's satisfaction by addressing any concerns or questions they may have

Air conditioning is the process of altering the properties of air to make it more comfortable for occupants.

• Air conditioning involves cooling, heating, dehumidifying, and ventilating indoor air.

• It works by using a refrigeration cycle to remove heat and moisture from the air.

• Air conditioning systems can be central or individual units, and can be used in residential, commercial, and industrial settings.

• Examples of air conditioning systems include window units, split systems, an...read more

Preventive maintenance is important to ensure the efficient and reliable operation of HVAC systems.

• Preventive maintenance helps identify and address potential issues before they become major problems.

• Regular maintenance improves energy efficiency and reduces energy consumption.

• It extends the lifespan of HVAC equipment and reduces the need for costly repairs or replacements.

• Preventive maintenance ensures optimal indoor air quality and comfort for occupants.

• It helps comply with...read more

Chemicals can be added to a chiller for descaling by following specific procedures to ensure safety and effectiveness.

• Determine the type and amount of chemical needed based on the chiller's size and condition

• Follow manufacturer's instructions for dilution ratios and mixing procedures

• Use appropriate personal protective equipment (PPE) when handling chemicals

• Ensure proper ventilation in the area where the chemicals are being added

• Flush the chiller system with water after adding...read more

Cooling tower capacity refers to the amount of heat that can be removed from a system by the cooling tower.

• Cooling tower capacity is typically measured in tons of refrigeration or kilowatts.

• It is influenced by factors such as the flow rate of water, the temperature difference between the inlet and outlet water, and the wet bulb temperature.

• Cooling tower capacity can be calculated using the formula: Q = mcΔT, where Q is the heat load, m is the flow rate of water, c is the spec...read more

A rack system is a type of HVAC system that uses multiple smaller units to cool or heat a large space.

• Rack systems are commonly used in commercial buildings and data centers.

• They consist of multiple smaller units, or racks, that work together to cool or heat a large space.

• Each rack contains its own compressor, evaporator, and condenser.

• The racks are connected to a central control system that manages the temperature and airflow.

• Rack systems are more energy-efficient than tradi...read more

The refrigeration cycle in HVAC and AC systems involves the process of absorbing heat from indoor air and releasing it outside.

• Refrigerant absorbs heat from indoor air through the evaporator coil

• The refrigerant is then compressed into a high-pressure, high-temperature gas in the compressor

• The hot gas releases heat outside through the condenser coil

• The refrigerant then expands and cools down in the expansion valve before repeating the cycle

HVAC work involves installing, maintaining, and repairing heating, ventilation, and air conditioning systems. Compressors are a type of HVAC component that pressurizes refrigerant gas.

• HVAC work includes installing, maintaining, and repairing heating, ventilation, and air conditioning systems

• Compressors are a type of HVAC component that pressurizes refrigerant gas

• There are different types of compressors used in HVAC systems such as reciprocating, rotary, and scroll compressors

Validation process in HVAC involves verifying that the system meets specified requirements and functions correctly.

• Validation process ensures that the HVAC system is installed correctly and operates as intended.

• It involves testing the system to confirm that it meets design specifications and performance criteria.

• Validation may include checking airflow, temperature control, humidity levels, and energy efficiency.

• Documentation of the validation process is important for complian...read more

The approach in chiller involves understanding the components, troubleshooting common issues, and performing regular maintenance.

• Understand the basic components of a chiller such as the compressor, condenser, evaporator, and expansion valve.

• Troubleshoot common issues like low refrigerant levels, dirty condenser coils, or faulty sensors.

• Perform regular maintenance tasks like cleaning coils, checking for leaks, and ensuring proper airflow.

• Use specialized tools like pressure gau...read more

The color of the RJ45 connector cord can vary depending on the specific application or standard being followed.

• The most common color coding for RJ45 connector cords is T568A and T568B.

• T568A uses a green-white, green, orange-white, blue, blue-white, orange, brown-white, and brown color sequence.

• T568B uses an orange-white, orange, green-white, blue, blue-white, green, brown-white, and brown color sequence.

• Other color codes may be used for specific purposes or in different count...read more

There are two types of compressors used in HVAC systems.

• The two types of compressors are reciprocating and rotary compressors.

• Reciprocating compressors use pistons to compress refrigerant gas.

• Rotary compressors use rotating blades to compress refrigerant gas.

• Reciprocating compressors are commonly used in smaller HVAC systems.

• Rotary compressors are commonly used in larger HVAC systems.

There are several types of detectors used in HVAC systems.

• Smoke detectors

• Carbon monoxide detectors

• Gas leak detectors

• Flame detectors

• Temperature detectors

• Humidity detectors

• Motion detectors

Actuator is a device that converts electrical energy into mechanical motion.

• Actuators are used in HVAC systems to control the flow of air, water, or steam.

• They can be electric, pneumatic, or hydraulic.

• Examples of actuators include valves, dampers, and motors.

• Actuators are essential for maintaining temperature, humidity, and air quality in HVAC systems.

HVAC stands for Heating, Ventilation, and Air Conditioning.

• HVAC stands for Heating, Ventilation, and Air Conditioning

• HVAC is responsible for maintaining indoor air quality and comfort

• HVAC systems include components like furnaces, air conditioners, and ventilation ducts

Maintaining differential pressure involves regular monitoring, adjusting airflow, checking filters, and ensuring proper equipment functioning.

• Regularly monitor differential pressure readings to ensure they are within acceptable range

• Adjust airflow dampers to balance pressure between different areas

• Check and replace air filters regularly to prevent blockages and maintain proper airflow

• Ensure equipment such as fans and ductwork are functioning properly to maintain desired press...read more

Maintaining relative humidity and temperature is crucial for HVAC systems to ensure comfort and efficiency.

• Regularly check and calibrate thermostats and humidistats

• Ensure proper insulation and sealing of windows and doors to prevent heat loss or gain

• Regularly clean and replace air filters to maintain airflow and prevent buildup of dust and debris

• Use programmable thermostats to adjust temperature settings based on occupancy and time of day

• Consider installing a humidifier or de...read more

PAC full form is Package Air Conditioner.

• PAC is a type of air conditioning system that is self-contained and can be installed in a single package.

• It is commonly used in commercial and industrial settings.

• PAC units are designed to be compact and easy to install, making them a popular choice for retrofitting older buildings.

• Some examples of PAC units include rooftop units, wall-mounted units, and floor-mounted units.

HVAC system operation involves the control and regulation of heating, ventilation, and air conditioning systems to maintain desired indoor conditions.

• HVAC systems are responsible for heating, cooling, and ventilating buildings.

• They consist of various components such as furnaces, air conditioners, heat pumps, fans, and ductwork.

• The operation of HVAC systems involves controlling temperature, humidity, and air quality.

• Thermostats are used to set desired temperatures and activate...read more

HVAC works by controlling the temperature, humidity, and air quality in a building through heating, ventilation, and air conditioning systems.

• HVAC systems use a combination of heating, cooling, and ventilation to maintain a comfortable indoor environment.

• Heating is typically provided by a furnace or boiler, while cooling is achieved through air conditioning units or heat pumps.

• Ventilation involves the exchange of indoor and outdoor air to improve air quality and remove pollut...read more

Processing in AHU involves filtering, heating or cooling, and distributing air throughout a building.

• Start by ensuring the air filters are clean and in good condition.

• Adjust the temperature settings on the AHU to provide the desired heating or cooling.

• Check the fan and motor to ensure they are functioning properly.

• Inspect the ductwork for any leaks or blockages that may hinder air flow.

• Monitor the air pressure and adjust as needed to maintain proper air distribution.

• Regular m...read more

RH control refers to the regulation of relative humidity levels in a given space.

• RH control is achieved through the use of humidifiers and dehumidifiers.

• Humidifiers add moisture to the air to increase relative humidity, while dehumidifiers remove moisture to decrease relative humidity.

• RH control is important for maintaining comfort, preventing mold growth, and protecting sensitive equipment.

• For example, in a residential setting, a humidifier may be used in the winter to preve...read more

ISRO stands for Indian Space Research Organisation.

• ISRO stands for Indian Space Research Organisation

• It is the space agency of the Government of India

• ISRO is responsible for the country's space program including satellite launches and space exploration

Hvac validation procedure ensures that the system is operating as per design and meets the required standards.

• The procedure involves testing and verifying the performance of the system components.

• It includes checking the airflow, temperature, pressure, and humidity levels.

• The validation process also involves verifying the control system and safety features.

• Documentation of the validation process is essential for compliance and future reference.

• Examples of validation tests inc...read more

HVAC problems can be solved by identifying the root cause and applying appropriate troubleshooting techniques.

• Conduct a thorough inspection of the HVAC system to identify the problem

• Check for common issues such as clogged filters, faulty thermostats, and refrigerant leaks

• Use diagnostic tools such as pressure gauges and thermometers to pinpoint the issue

• Apply appropriate troubleshooting techniques such as cleaning, repairing, or replacing faulty components

• Regular maintenance c...read more

There are two main types of compressors: positive displacement compressors and dynamic compressors.

• Positive displacement compressors include reciprocating, rotary, and scroll compressors.

• Dynamic compressors include centrifugal and axial compressors.

• Each type of compressor has its own advantages and disadvantages based on the application.

Refrigeration cycle is a process in which a refrigerant absorbs heat from a low-temperature area and releases it in a high-temperature area.

• Refrigerant absorbs heat from the evaporator coil and evaporates into a gas

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

• The hot gas flows through the condenser coil, releasing heat and condensing back into a liquid

• The liquid refrigerant passes through the expansion valve, where it expands and cools down befo...read more

The fan coil unit (FCU) is full of water or condensate.

• Check for clogged drain lines or condensate pump failure.

• Inspect the drain pan for any leaks or cracks.

• Ensure the unit is properly leveled to allow for proper drainage.

• Check the air filter for any blockages that may be causing the unit to overflow.

A mechanical seal is a device that helps to prevent leakage between two moving parts in a machine.

• A mechanical seal is typically used in pumps, compressors, and other rotating equipment.

• It consists of two main components - a stationary part attached to the pump housing and a rotating part attached to the pump shaft.

• The seal prevents fluid from leaking out of the pump by creating a barrier between the stationary and rotating parts.

• Common materials used for mechanical seals inc...read more

The refrigeration cycle is a process of removing heat from a space or substance. Types of chillers include absorption, centrifugal, and reciprocating.

• The refrigeration cycle involves four main components: compressor, condenser, expansion valve, and evaporator

• Absorption chillers use a heat source to drive the refrigeration cycle, while centrifugal and reciprocating chillers use mechanical energy

• Centrifugal chillers are commonly used in large commercial buildings, while absorpt...read more

I am currently earning $60,000 per year.

• Current salary is $60,000 per year

• Salary is subject to negotiation based on job responsibilities and benefits

• Previous salary may not accurately reflect current market value