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1. • What is the basic principle of HVAC?
• Heating, ventilation, and air conditioning
(HVAC) is a system of controlling indoor
temperature, humidity, and indoor air quality.
The main principles of the system are heat
transfer, thermodynamics, and fluid
mechanics

2. • What are the three types of HVAC?
• Split, hybrid heat split, and ductless mini-split
heating are three of the most common types
of HVAC systems to choose from for your
Homewood, Alabama, home

3. • How does HVAC work step by step?
• Step 1: Heat is absorbed by the evaporator
coil. The warm air inside your house is drawn
in through a vent and blows over the cold
evaporator coil. ...
• Step 2: Compressor raises the refrigerant
temperature. ...
• Step 3: Heat is transferred outside. ...
• Step 4: Refrigerant gets cold; process repeats.

5. • What is HVAC and its types?
• Heating, ventilation, and air
conditioning (HVAC) system is designed to
achieve the environmental requirements of
the comfort of occupants and a process. HVAC
systems are more used in different types of
buildings such as industrial, commercial,
residential and institutional buildings

7. • What are the four 4 main types of HVAC systems?
• HVAC systems are divided into four categories
which come in different sizes and specifications
that fit into your home or business.
• Heating and cooling split systems. ...
• Hybrid split system. ...
• Duct free (Mini-split) ...
• Packaged heating and air conditioning system.

9. • What is HVAC full concept?
• Defined: HVAC stands for Heating, Ventilation,
and Air Conditioning. HVAC refers to the
different systems used for moving air between
indoor and outdoor areas, along with heating
and cooling both residential and commercial
buildings.

10. • What are the two types of HVAC?
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• Each type of HVAC system falls into one of two
categories: ducted or ductless. In a ducted
system, the main unit pushes air through a
series of air ducts to cool or heat a building.
Ductless systems, on the other hand, lack air
ducts and use alternative methods to
distribute treated air throughout a space.10-
Feb-2022

12. • What is difference between AC and HVAC?
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• To keep things simple: the system designed to
cool the air is the AC unit, and the system
designed to heat the air and push moisture
out through the vents, is the HVAC unit.

14. • What is S1 and S2 HVAC?
• S, S1, or S2. S terminals are for outdoor
temperature sensors. ecobee thermostats
obtain weather data over Wi-Fi so S wires
aren't necessary. L. The L wire can be used to
power indicator lights on older thermostats.

15. • What is HVAC and its function?
• The main purposes of a Heating, Ventilation
and Air-Conditioning (HVAC) system are to
help maintain good indoor air quality (IAQ)
through adequate ventilation with filtration
and provide thermal comfort. HVAC systems
are among the largest energy consumers in
schools.05-Dec-2022

16. • What is AHU in HVAC?
• The air handling unit (AHU) is the heart of
central air conditioning. It collects outside air
and room air, removes dust and other
particles from the collected air, adjusts the
temperature and humidity and t

17. • Which gas is used in AC?
• R22 with a molecular formula of CHCLF2 is
the most widely used refrigerant for the Air-
conditioners. It constantly changes its
state(Solid, Liquid and gas) at different
temperature. Caution : Refrigerants are too
dangerous at high

19. • What are the three main function of HVAC?
• Overview. The three major functions
of heating, ventilation, and air
conditioning are interrelated, especially with
the need to provide thermal comfort and
acceptable indoor air quality within
reasonable installation, operation, and
maintenance costs.

21. • What is AHU and FCU?
• An air handling unit (AHU) operates by
bringing in fresh air from the outside, while a
fan coil unit (FCU) generally recirculates and
conditions the air in an interior space.26-May-
2022

22. • What type of heat is HVAC?
• Image result
• Heating Systems
• Heating units can be categorized into furnaces
that provide heated air through ductwork,
which is a popular type of heating system in
the United States such as boilers that heat
water for steam radiators or forced-water
systems with baseboard radiators, electric

24. • What is 3phase HVAC?
• Three phase air conditioners require a three
phase power supply and are generally used for
models with larger heating/cooling capacity.
Three phase electric power is a common
method of alternating current electric power
generation, transmission, and distribution.

25. • What is a 3 stage HVAC system?
• Multistage systems have steps, usually two,
such as “low” and “high“. A 3-stage system
might have “low”, “medium”, and “high”.) Like
a hair dryer or a ceiling fan, they have some
granularity to their output.07-Mar-2018

26. • What is the difference between VRF and
HVAC?
• VRF systems are far more flexible than
traditional packaged or ducted HVAC systems
(where a single outdoor unit circulates
conditioned air or cold water throughout all
zones of a building), offering individualized
zone control and a high degree of
decentralized control ability.

27. • What is the full form of VRF?
• VRV (variable refrigerant volume) and VRF
(variable refrigerant flow) are two different
terms for the same technology.

29. • What is HVAC size?
• HVAC units are sized to the amount of cubic
feet that they need to heat and cool in a
space. If your unit is sized properly, it can have
a big impact on energy consumption and
heating and coolin

31. • Is HVAC mechanical or electrical?
• mechanical engineering
• Based on thermodynamic, fluid mechanics
and heat transfer principles, heating,
ventilation and air conditioning (HVAC)
systems fall under the umbrella of mechanical
engineering. HVAC is a critical element of
residential, commercial and mixed-use
buildings.06-Apr-2020

32. • What is L1 and L2 in HVAC?
• L1 and L2 represent the two poles on an AC
power supply. L1 and L2 provide power to the
components on the line side of the circuit.20-
Apr-2021

33. • Why is it called HVAC?
• It is an acronym for "heating, ventilation, and
air conditioning. There is a lot that falls under
the umbrella of HVAC, and it's time that
homeowners got the 411. Essentially, anything
regarding the home's airflow and air quality is
summed up with this term. HVAC
professionals do more than just repair
things.10-Apr-202

34. • How many levels are there in HVAC?
• Depending on the equipment you will be
handling, there are four different levels of
certification you will need to obtain.03-Dec-
2020

35. • Are there different types of HVAC?
• There are four main types of HVAC systems.
There are split systems, hybrid systems, duct-
free systems, and packaged heating and air
systems. Each of these types of HVAC units
have pro's and con's, and knowing these
factors can help you decide which is best for
you.10-Oct-2022

37. • What is the difference between AHU and
HVAC?
• AHU, which is Air Handling Unit is an
appliance used to circulate air. HVAC is
Heating, Ventilating and Air Conditioning
system. HVAC is the central unit to which
AHU is connected. AHU is only a part of HVAC
and as such there is hardly any difference
between then two.22

38. • What are the most common HVAC problems?
• Get Answers to the 10 Most Common HVAC
Problems
• LACK OF MAINTENANCE. ...
• DIRTY FILTERS. ...
• PILOT OR IGNITION PROBLEMS. ...
• THERMOSTAT MALFUNCTIONS. ...
• MECHANICAL WEAR AND TEAR. ...
• UNUSUAL FURNACE NOISES. ...

39. • What color wire is C?
• Blue wires
• Blue wires are also called “C” wires because
they are the Common wire. C wires are
necessary for any “smart” thermostat that
needs to be connected to a power source
24/7, regardless of your heat pump type.04-
Feb-2020

41. • What is RC vs Rh?
• There is no standard for the color of the RH
wire, but most units use a red one. The RC
wire, on the other hand, refers to “red
cooling”. It's the same with the RH wire in that
it powers the thermostat. For the RC, it
powers the cooling system.

42. • What is W2 HVAC?
• The wire in the W2 connector controls the
second stage of heat. Learn more about
multistage systems. If you have a heat pump.
If you have a heat pump, the W2 wire may
control your auxiliary heat. Auxiliary heat
helps heat your home when it's too cold
outside outside for your heat pump to work
efficiently.

43. • Is HVAC air or heat?
• HVAC stands for heating, ventilation, and air
conditioning. It refers to the systems that
regulate and move heated and cooled air
throughout residential and commercial
buildings, from homes to offices to indoor
stadium

45. • What type of work is HVAC?
• HVAC technicians are skilled professionals
who install, repair and maintain heating,
ventilation, air conditioning, and
refrigeration systems that control the quality
and temperature of the air inside residential
and commercial buildings.02-Nov-2021

47. • What is the difference between MEP and
HVAC?
• HVAC is about providing comfortable
conditioned air for residential, commercial,
and multi-use buildings. MEP, however, refers
to mechanical, electrical, and plumbing
considerations of design and construction of
buildings, one of which is HVAC.23-Nov-2021
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48. • What is the difference between MEP and
HVAC?
• HVAC is about providing comfortable
conditioned air for residential, commercial,
and multi-use buildings. MEP, however, refers
to mechanical, electrical, and plumbing
considerations of design and construction of
buildings, one of which is HVAC.23-Nov-2021

50. • What does VFD stand for in HVAC?
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• The increasing advancement of electronic and
control technology greatly improves the
performance of variable speed drives. Variable
frequency drives (VFDs) are being used in the
HVAC industry more frequently and in more
applications. They can modulate the motor
speed very smoothly within a wide range.

52. • What is HVAC chiller?
• A chiller (cooling water circulation device) is a
general term for a device that controls the
temperature by circulating a liquid such as
water or heat medium as a cooling liquid
whose temperature was adjusted by the
refrigerant cycle.
•

53. • HOW AHU CFM is calculated?
• To change it 2 times per hour (ACH = 2), we
need to deliver 4,800 ft3 per hour. CFM is a
'ft3 per minute' unit. That's why we need
to divide the total volume by 60; hence
4,800/60 = 80 CFM.

55. • Which gas is harmful in AC?
• Freon
• Most air conditioners use a chemical
called Freon as a refrigerant. Freon is a stable,
nonflammable, moderately toxic gas that is
tasteless and mostly odorless. Freon contains
chlorofluorocarbons (CFCs), which are known
to deplete the ozone. For this reason,
refrigerant leaks are considered
environmentally hazardous.22-May-2015

56. • Is CFC used in AC?
• Chlorofluorocarbons that is called as freons
are nonreactive, non inflammable, nontoxic
organic molecules. So they are widely used in
refrigerators and air conditioners.

57. • Which chemical is used in AC?
• Chlorofluorocarbons. (CFCs) are the chemical
compounds made of chlorine, fluorine and
carbon elements, which are used in
refrigerators, air conditioners and aerosol
sprays, and damage ozone layer when
released in the air.

58. • What is the most important part of HVAC?
• The heat exchanger is the most important
part of your heater or furnace, because it's the
tool that heats the air. Typical, furnaces pull
air in from the outside. The heat exchanger
heats the air quickly, and the air is blown into
your home.07-Feb-2018

59. • What is the HVAC equipment?
• HVAC stands for heating, ventilation and air
conditioning systems. This system is
responsible for heating and cooling your home
and includes products like furnaces, air
conditioners, heat pumps as well as ductwork,
thermostats and other home comfort
controls.29-Aug-2022

60. • What are the elements of HVAC?
• Some of the most important parts of your
HVAC system are your heat exchanger, blower
motor, combustion chamber, condenser,
evaporator, and thermostat.17-Feb-2017

61. • What is VAV and CAV?
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• Variable air volume (VAV) is a type of heating,
ventilating, and/or air-conditioning (HVAC)
system. Unlike constant air volume (CAV)
systems, which supply a constant airflow at a
variable temperature, VAV systems vary the
airflow at a constant or varying temperature.

63. • What are types of FCU?
• Fan Coil Unit falls principally into two main
types: blow through and draw through. As
the names suggest, in the first type the fans
are fitted behind the heat exchanger, and in
the other type the fans are fitted in front the
coil such that they draw air through it.

65. • What is FCU size?
• How Big Are Fan Coil Units? Typically, fan coil
units are around 500 – 2,000mm wide and
between 160 – 400 mm deep. The typical
length is 500 – 800 mm.

67. • Is HVAC a heat exchanger?
• A heat exchanger is a component in an HVAC
system that transfers thermal energy from
one medium to another. Two main types of
heat exchangers are evaporator coils and
condenser coils, both of which assist in the
heating and cooling of homes and
buildings.15-Sept-2021

68. • Is a thermostat HVAC?
• In its simplest form, a thermostat is a device
that turns the HVAC unit ON and OFF to
maintain the temperature at the thermostat
close to the desired setting. It is typically
mounted on an interior wall and, alone,
cannot measure temperature throughout the
house – only near the thermostat.07-Jan-2020

70. • Is HVAC gas or electric?
• Forced air heating can be from both gas and
electricity. The difference between these is
that the gas-powered heating system uses a
heat exchanger and burner that produces
hear, whereas the electric-powered heating
systems use an electric element, which is
similar to an electric radiator.

71. • How many volts is 3-phase?
• A three-phase connection, on the other hand,
consists of three separate conductors that are
needed for transmitting electricity. In a single-
phase power supply system, the voltage may
reach up to 230 Volts. But on a three-phase
connection, it can carry a voltage of up to 415
Volts.

72. • What is the input voltage for HVAC?
• The maximum input voltage for connection to
the HVAC/HVDC power supply should not
exceed 305 VAC and 400 VDC .
• Is all 3-phase 415V?
• 3 phase power has four wires; three actives
and one neutral, and supplies power at both
240V and 415V.

73. • What are the major cycle in HVAC?
• For this reason, all air conditioners use the
same cycle of compression, condensation,
expansion, and evaporation in a closed
circuit. The same refrigerant is used to move
the heat from one area, to cool this area, and
to expel this heat in another area.

74. • How many cycles per hour for AC?
• three times
• How many types of HVAC pumps are there?
• There are several types of pumps used in
HVAC heating & cooling systems, but the most
common in use today is the centrifugal pump.
end-suction, single- and multi-stage split-case,
and vertical in-line pumps.

75. • What are the three types of HVAC?
• Split, hybrid heat split, and ductless mini-split
heating are three of the most common types
of HVAC systems to choose from for y
• What is TR in HVAC?
• A ton of refrigeration (TR or TOR), also called
a refrigeration ton (RT), is a unit of power
used in some countries (especially in North
America) to describe the heat-extraction
capacity of refrigeration and air conditioning

76. • Which is better VRV or VRF?
• For starters, they actually mean the same
thing! VRV is term copyrighted by Daikin, one
of the true industry leaders in HVAC
equipment and technology. VRF refers to the
same basic technology used in those systems
manufactured by other companies—Fujitsu,
for one, makes some great variable refrigerant
flow systems.

77. • What is difference between Ahu and VRF?
• Variable refrigerant flow systems (VRF) are a
more sophisticated version of the minisplit
HVAC system used throughout the world. They
distribute the refrigerant instead of piping hot
water and chilled water to each fan coil unit
(FCU) or air handling unit (AHU).16-Dec-2009

78. • What is VLAN and VRF?
• Essentially, VRF uses the same methods of
virtualization as virtual LANs (VLANs). They are
equivalent to the Layer 3 version of a
Transmission Control Protocol/IP layer of a
VLAN. Because both routing instances operate
independently, they can use the same IP
address without any friction.

79. • Why VRF is used?
• Virtual routing and forwarding (VRF) IP
technology allows users to configure multiple
routing table instances to simultaneously co-
exist within the same router. Overlapping IP
addresses can be used without conflicting
because the multiple routing instances are
independent, and can select different
outgoing interfaces.

80. • How many CFM is a HVAC system?
• A typical air conditioning system produces 350
CFM – 400 CFM per ton of air conditioning.

81. • How To Size Your HVAC Unit
• Figuring out how to properly size your HVAC
unit is vital for your business. If it is not sized
correctly for your property, it could cause a
variety of issues from running non-stop to
running in short bursts constantly throughout
the day, insufficient moisture removal, to
inconsistent temperatures throughout your
space. All of these problems will make for a
noisy, uncomfortable environment, even a

82. • What is a 5 ton HVAC?
• A 5 ton unit will typically cool between 1500
square feet and 1800 square feet. See our free
system sizing calculator if you need help. The
broad range for sizing is 500-600 square feet
of living space per ton of cooling.

83. • What is HVAC purpose?
• The main purposes of a Heating, Ventilation
and Air-Conditioning (HVAC) system are to
help maintain good indoor air quality (IAQ)
through adequate ventilation with filtration
and provide thermal comfort. HVAC systems
are among the largest energy consumers in
schools.05-Dec-2022

84. What is HVAC purpose?
The main purposes of a Heating,
Ventilation and Air-Conditioning (HVAC)
system are to help maintain good indoor air
quality (IAQ) through adequate ventilation
with filtration and provide thermal comfort.
HVAC systems are among the largest
energy consumers in schools.05-Dec-2022

85. • What type motor is HVAC?
• PERMANENT SPLIT CAPACITOR MOTORS (PSC
MOTORS)
• The PSC motor is the most common motor in
HVAC applications, often considered the
workhorse of the HVAC industry. Their design
includes fewer wearable components,
allowing for a cost-effective, reliable, and
versatile operation.03-Oct-2021

86. • What is MEP work?
• In the construction world, MEP stands for
“mechanical, electrical and plumbing.” MEP
engineering is the science and art of planning,
designing and managing the MEP systems of
a building. An MEP design company
specializes in those skills.

87. • What is T1 T2 T3 in HVAC?
• Ambient temperatures with a T1 class range
from -7°C to +43°C, T2 from -7°C to +35°C, and
T3 from -7°C to +52°C.23-Jun-2021