BOMA HVAC | TOP SCORES MADE SIMPLE | TRUSTED
TEST SOLUTIONS!
What happens when room temperature soda is poured into a glass of ice ? - Answer:
The ice melts because it is absorbing heat from the soda .
The compressor in a refrigeration system - Answer: pumps the refrigerant throughout
the system
To control ice build - up on a heat pump outdoor coil in the heating cycle a ______ is
used . - Answer: pressure differential switch
The total pressure of a confined mixture of gases is the sum of the pressures of each of
the gases in the mixture . This is known as - Answer: Dalton's Law
When moisture is present in a refrigeration system , it will react with the refrigerant and
the oil to form_ - Answer: acid
A direct expansion - type evaporator is also called a - Answer: dry-type evaporator
Positive displacement compressors have crankcase heat to - Answer: prevent
refrigerant migration to the compressor
If the power element of a TX valve loses its charge the - Answer: refrigerant flow to the
coil will stop
The pressure in a refrigeration system is changed in the - Answer: compressor and
expansion device
Where is cooling produced - Answer: In the evaporator
1
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,Where is heat content the highest - Answer: Entering the compressor
Where is heat content decreased the most ? - Answer: The condenser
Where is the compressor located - Answer: Between the condenser and evaporator
Where does the state of refrigerant change from liquid to a vapor - Answer: The
evaporator
What part of the system is pressure the lowest - Answer: The evaporator
(T/F) A Compressor raises the pressure and lowers the temperature of the refrigerant -
Answer: False
Rotary is what type compressor - Answer: Positive displacement
If a thermal expansion valve stays closed what would be the result - Answer: The valve
would not be the load and the unit will heat up
What type of metering device is used in a centrifugal chiller - Answer: A high side float
Which compressor require the least amount of maintenance - Answer: Centrifugal
What opens the TXV - Answer: The power element of the assembly
T/F the purpose of a solenoid valve in a refrigeration system is to start and stop the
refrigerant flow - Answer: True
2
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,What causes oil to foam - Answer: Refrigerant in the oil
What determines the corrosion tendency of oil - Answer: The sulfur content
What would cause a compressor to overload - Answer: Starting under a warm
evaporator load
The evaporator im a refrigeration system - Answer: Absorbs heat from the product to be
cooled
Moisture reacts with refrigerant and oil to form - Answer: Acid
A direct expansion type evaporator is also called a - Answer: Dry type evaporator
The condenser - Answer: rejects the heat from the refrigerant
Positive displacement compressors have crankcase heat to - Answer: Prevent the
refrigerant migration to the compressor
If the power element of a TX valve loses its charge, the___. - Answer: refrigerant flow to
the coil will stop
Most of the heat energy in the suction vapor entering the compressor is - Answer:
Latent heat
If the thermal bulb assembly develops a leak , what will occur - Answer: The bulb
pressure will reduce and the valve will close
3
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, The approach of a cooling tower is the - Answer: difference in temperature between the
entering air wet-bulb temperature and the sump water temperature
At what locations in a refrigeration system does the saturation pressure correspond to
the saturation temperature - Answer: Evaporator and condenser
A split phase motor can use what to energize and de-energize the start winding ? -
Answer: Potential relay, current relay, and a centrifugal switch
Temperature is an indicaron of the - Answer: Amount of molecular activity in the material
What can cause high suction pressures - Answer: Defective compressor valves
What can cause an expansion valve to operate erratically - Answer: Vapor in the liquid
line, bad compressor, low refrigerant charge.
What is a probable cause of a broken valve in the compressor - Answer: Liquid slugging
If a heat pump has insufficient cooling and low suction pressure what is the cause -
Answer: Partially iced coil
If the power circuit and a control circuit of a cooling system are continuous the problem
is ? - Answer: A faulty compressor motor
What could cause a system to stop and not restart? - Answer: The compressor
What seals are used on low speed systems ? - Answer: Packing glands
How far apart are expansion loops - Answer: Every 50 feet
4
APPHIA - Crafted with Care and Precision for Academic Excellence.
TEST SOLUTIONS!
What happens when room temperature soda is poured into a glass of ice ? - Answer:
The ice melts because it is absorbing heat from the soda .
The compressor in a refrigeration system - Answer: pumps the refrigerant throughout
the system
To control ice build - up on a heat pump outdoor coil in the heating cycle a ______ is
used . - Answer: pressure differential switch
The total pressure of a confined mixture of gases is the sum of the pressures of each of
the gases in the mixture . This is known as - Answer: Dalton's Law
When moisture is present in a refrigeration system , it will react with the refrigerant and
the oil to form_ - Answer: acid
A direct expansion - type evaporator is also called a - Answer: dry-type evaporator
Positive displacement compressors have crankcase heat to - Answer: prevent
refrigerant migration to the compressor
If the power element of a TX valve loses its charge the - Answer: refrigerant flow to the
coil will stop
The pressure in a refrigeration system is changed in the - Answer: compressor and
expansion device
Where is cooling produced - Answer: In the evaporator
1
APPHIA - Crafted with Care and Precision for Academic Excellence.
,Where is heat content the highest - Answer: Entering the compressor
Where is heat content decreased the most ? - Answer: The condenser
Where is the compressor located - Answer: Between the condenser and evaporator
Where does the state of refrigerant change from liquid to a vapor - Answer: The
evaporator
What part of the system is pressure the lowest - Answer: The evaporator
(T/F) A Compressor raises the pressure and lowers the temperature of the refrigerant -
Answer: False
Rotary is what type compressor - Answer: Positive displacement
If a thermal expansion valve stays closed what would be the result - Answer: The valve
would not be the load and the unit will heat up
What type of metering device is used in a centrifugal chiller - Answer: A high side float
Which compressor require the least amount of maintenance - Answer: Centrifugal
What opens the TXV - Answer: The power element of the assembly
T/F the purpose of a solenoid valve in a refrigeration system is to start and stop the
refrigerant flow - Answer: True
2
APPHIA - Crafted with Care and Precision for Academic Excellence.
,What causes oil to foam - Answer: Refrigerant in the oil
What determines the corrosion tendency of oil - Answer: The sulfur content
What would cause a compressor to overload - Answer: Starting under a warm
evaporator load
The evaporator im a refrigeration system - Answer: Absorbs heat from the product to be
cooled
Moisture reacts with refrigerant and oil to form - Answer: Acid
A direct expansion type evaporator is also called a - Answer: Dry type evaporator
The condenser - Answer: rejects the heat from the refrigerant
Positive displacement compressors have crankcase heat to - Answer: Prevent the
refrigerant migration to the compressor
If the power element of a TX valve loses its charge, the___. - Answer: refrigerant flow to
the coil will stop
Most of the heat energy in the suction vapor entering the compressor is - Answer:
Latent heat
If the thermal bulb assembly develops a leak , what will occur - Answer: The bulb
pressure will reduce and the valve will close
3
APPHIA - Crafted with Care and Precision for Academic Excellence.
, The approach of a cooling tower is the - Answer: difference in temperature between the
entering air wet-bulb temperature and the sump water temperature
At what locations in a refrigeration system does the saturation pressure correspond to
the saturation temperature - Answer: Evaporator and condenser
A split phase motor can use what to energize and de-energize the start winding ? -
Answer: Potential relay, current relay, and a centrifugal switch
Temperature is an indicaron of the - Answer: Amount of molecular activity in the material
What can cause high suction pressures - Answer: Defective compressor valves
What can cause an expansion valve to operate erratically - Answer: Vapor in the liquid
line, bad compressor, low refrigerant charge.
What is a probable cause of a broken valve in the compressor - Answer: Liquid slugging
If a heat pump has insufficient cooling and low suction pressure what is the cause -
Answer: Partially iced coil
If the power circuit and a control circuit of a cooling system are continuous the problem
is ? - Answer: A faulty compressor motor
What could cause a system to stop and not restart? - Answer: The compressor
What seals are used on low speed systems ? - Answer: Packing glands
How far apart are expansion loops - Answer: Every 50 feet
4
APPHIA - Crafted with Care and Precision for Academic Excellence.
