HVAC FINAL EXAM QUESTIONS WITH COMPLETE SOLUTIONS
VERIFIED GRADED A+
Which of the following would have the greatest effect on the heat content of the
refrigerant?
A) The refrigerant's humidity
B) The refrigerant's state
C) The refrigerant's temperature
D) The refrigerant's pressure
Correct Answer
B)
The refrigerant's state
A mechanical refrigeration system cools a room by:
Removing heat from the room.
The four types of cooling mechanisms are:
Evaporative, Thermoelectric, Absorption, Mechanical Compression.
Refrigeration can be defined as:
It moves the heat from the refrigerated area to another area.
Which of the following systems uses compression pumps and condensers to
cool the air?
A) Evaporative system
B) Thermoelectric system
C) Absorption system
D) Mechanical compression system
Correct Response
D) Mechanical compression system
,Which of the four types of refrigeration systems cools the air without removing
any heat from the air?
Evaporative systems
The order of the four main components of the refrigeration cycle is:
Compressor - condenser - metering device - evaporator.
The small line on a split system air conditioning unit is the:
Liquid line.
Where is the liquid receiver located?
On the high side just after the condenser
The line that connects the condenser to the metering device is called the:
Liquid line.
The discharge, liquid, and suction lines of a packaged unit are:
Located inside the unit.
The difference between a liquid receiver and a suction accumulator is that:
Receivers only allow liquid to leave while accumulators only allow vapor to leave.
On an R410A air conditioning system, the refrigerant leaving the ________ is 118
psig, 50°F, 100% superheated gas
evaporator
Optional components on the high side of a refrigeration system include:
Discharge line muffler, oil separator, liquid receiver, and liquid line filter-drier.
Optional components found on the low side of a refrigeration system include:
Suction line filter, accumulator, and evaporator pressure regulator.
The line that connects the evaporator to the compressor is called the:
Suction line.
The refrigerant is a high-pressure, warm, subcooled liquid at the inlet of the
metering device. The state of the refrigerant is:
100% liquid.
Which of the two refrigerant lines going to the compressor is larger?
The low pressure suction line
The two refrigerant lines connecting the inside and outside units of a split system
air conditioner are:
,Suction line and liquid line.
Where is the suction accumulator located?
On the low side just before the compressor
The line that connects the compressor to the condenser is called the:
Discharge line.
Which of the following compressors is not considered a positive displacement
compressor?
A) Reciprocating
B) Screw
C) Rotary
D) Centrifugal
Correct Response
D) Centrifugal
What is the lowest percentage of full capacity that a digital scroll can be safely
operated for extended periods?
The minimum capacity is 10% to insure that the compressor gets proper lubrication.
How does a reciprocating compressor operate?
In a reciprocating compressor, the piston is driven up and down in the cylinder by the
connecting rod and crankshaft.
Operating a hermetic compressor in a vacuum:
Can cause the motor to arc out because of the change in electrical resistance.
The function of the compressor in the refrigeration cycle is:
Raise the pressure and temperature of the refrigerant.
A compressor that compresses gas between a fixed spiral and an orbiting spiral
is a:
Scroll compressor.
An oil slinger is used with reciprocating compressors that are lubricated by:
Splash lubrication.
Which of the following is true of a medium-temperature refrigeration unit?
, A) It requires 1 hp to produce 1-1/3 tons of cooling.
B) It requires 1 hp to produce 1 ton of cooling.
C) It requires 1 hp to produce 1/3 ton of cooling.
D) It requires 1 hp to produce 2/3 ton of cooling.
Correct Answer
D) It requires 1 hp to produce 2/3 ton of cooling.
What type of compressors contain the compressor and motor together inside a
welded steel housing?
Hermetic compressors
All refrigeration compressors are designed to pump:
Only vapor.
Above what temperature do most refrigerant oils begin to break down
chemically?
300°F
The advantage of compliance in a scroll compressor is that:
The orbiting scroll can separate and unload to pass a small liquid slug.
Broken rods, broken valve plates, broken valves, and broken crankshafts are
symptoms of what type of mechanical failure?
Liquid slugging
Which compressor has a piston that is driven up and down in the cylinder by a
connecting rod and crankshaft?
A reciprocating compressor
The space left between the piston and the valve plate of a reciprocating
compressor when the piston is at the top of the cylinder is called:
The clearance volume.
What opens and closes the valves in a reciprocating compressor?
Pressure difference across the valves
Why does oil slugging occur in a compressor?
Oil slugging is caused by a sudden return of large amounts of refrigerant oil.
Hydraulic pressures will develop and break compressor parts if:
Liquid refrigerant enters the compressor cylinders.
VERIFIED GRADED A+
Which of the following would have the greatest effect on the heat content of the
refrigerant?
A) The refrigerant's humidity
B) The refrigerant's state
C) The refrigerant's temperature
D) The refrigerant's pressure
Correct Answer
B)
The refrigerant's state
A mechanical refrigeration system cools a room by:
Removing heat from the room.
The four types of cooling mechanisms are:
Evaporative, Thermoelectric, Absorption, Mechanical Compression.
Refrigeration can be defined as:
It moves the heat from the refrigerated area to another area.
Which of the following systems uses compression pumps and condensers to
cool the air?
A) Evaporative system
B) Thermoelectric system
C) Absorption system
D) Mechanical compression system
Correct Response
D) Mechanical compression system
,Which of the four types of refrigeration systems cools the air without removing
any heat from the air?
Evaporative systems
The order of the four main components of the refrigeration cycle is:
Compressor - condenser - metering device - evaporator.
The small line on a split system air conditioning unit is the:
Liquid line.
Where is the liquid receiver located?
On the high side just after the condenser
The line that connects the condenser to the metering device is called the:
Liquid line.
The discharge, liquid, and suction lines of a packaged unit are:
Located inside the unit.
The difference between a liquid receiver and a suction accumulator is that:
Receivers only allow liquid to leave while accumulators only allow vapor to leave.
On an R410A air conditioning system, the refrigerant leaving the ________ is 118
psig, 50°F, 100% superheated gas
evaporator
Optional components on the high side of a refrigeration system include:
Discharge line muffler, oil separator, liquid receiver, and liquid line filter-drier.
Optional components found on the low side of a refrigeration system include:
Suction line filter, accumulator, and evaporator pressure regulator.
The line that connects the evaporator to the compressor is called the:
Suction line.
The refrigerant is a high-pressure, warm, subcooled liquid at the inlet of the
metering device. The state of the refrigerant is:
100% liquid.
Which of the two refrigerant lines going to the compressor is larger?
The low pressure suction line
The two refrigerant lines connecting the inside and outside units of a split system
air conditioner are:
,Suction line and liquid line.
Where is the suction accumulator located?
On the low side just before the compressor
The line that connects the compressor to the condenser is called the:
Discharge line.
Which of the following compressors is not considered a positive displacement
compressor?
A) Reciprocating
B) Screw
C) Rotary
D) Centrifugal
Correct Response
D) Centrifugal
What is the lowest percentage of full capacity that a digital scroll can be safely
operated for extended periods?
The minimum capacity is 10% to insure that the compressor gets proper lubrication.
How does a reciprocating compressor operate?
In a reciprocating compressor, the piston is driven up and down in the cylinder by the
connecting rod and crankshaft.
Operating a hermetic compressor in a vacuum:
Can cause the motor to arc out because of the change in electrical resistance.
The function of the compressor in the refrigeration cycle is:
Raise the pressure and temperature of the refrigerant.
A compressor that compresses gas between a fixed spiral and an orbiting spiral
is a:
Scroll compressor.
An oil slinger is used with reciprocating compressors that are lubricated by:
Splash lubrication.
Which of the following is true of a medium-temperature refrigeration unit?
, A) It requires 1 hp to produce 1-1/3 tons of cooling.
B) It requires 1 hp to produce 1 ton of cooling.
C) It requires 1 hp to produce 1/3 ton of cooling.
D) It requires 1 hp to produce 2/3 ton of cooling.
Correct Answer
D) It requires 1 hp to produce 2/3 ton of cooling.
What type of compressors contain the compressor and motor together inside a
welded steel housing?
Hermetic compressors
All refrigeration compressors are designed to pump:
Only vapor.
Above what temperature do most refrigerant oils begin to break down
chemically?
300°F
The advantage of compliance in a scroll compressor is that:
The orbiting scroll can separate and unload to pass a small liquid slug.
Broken rods, broken valve plates, broken valves, and broken crankshafts are
symptoms of what type of mechanical failure?
Liquid slugging
Which compressor has a piston that is driven up and down in the cylinder by a
connecting rod and crankshaft?
A reciprocating compressor
The space left between the piston and the valve plate of a reciprocating
compressor when the piston is at the top of the cylinder is called:
The clearance volume.
What opens and closes the valves in a reciprocating compressor?
Pressure difference across the valves
Why does oil slugging occur in a compressor?
Oil slugging is caused by a sudden return of large amounts of refrigerant oil.
Hydraulic pressures will develop and break compressor parts if:
Liquid refrigerant enters the compressor cylinders.
