BOMA HVAC EXAM QUESTIONS WITH
VERIFIED ANSWERS.
What happens when room temperature soda is poured into a glass of ice ? - ANS The ice
melts because it is absorbing heat from the soda .
The compressor in a refrigeration system - ANS pumps the refrigerant throughout the system
To control ice build - up on a heat pump outdoor coil in the heating cycle a ______ is used . -
ANS 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 - ANS Dalton's Law
When moisture is present in a refrigeration system , it will react with the refrigerant and the oil
to form_ - ANS acid
A direct expansion - type evaporator is also called a - ANS dry-type evaporator
Positive displacement compressors have crankcase heat to - ANS prevent refrigerant
migration to the compressor
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
,If the power element of a TX valve loses its charge the - ANS refrigerant flow to the coil will
stop
The pressure in a refrigeration system is changed in the - ANS compressor and expansion
device
Where is cooling produced - ANS In the evaporator
Where is heat content the highest - ANS Entering the compressor
Where is heat content decreased the most ? - ANS The condenser
Where is the compressor located - ANS Between the condenser and evaporator
Where does the state of refrigerant change from liquid to a vapor - ANS The evaporator
What part of the system is pressure the lowest - ANS The evaporator
(T/F) A Compressor raises the pressure and lowers the temperature of the refrigerant -
ANS False
Rotary is what type compressor - ANS Positive displacement
If a thermal expansion valve stays closed what would be the result - ANS The valve would not
be the load and the unit will heat up
What type of metering device is used in a centrifugal chiller - ANS A high side float
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
,Which compressor require the least amount of maintenance - ANS Centrifugal
What opens the TXV - ANS 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 - ANS True
What causes oil to foam - ANS Refrigerant in the oil
What determines the corrosion tendency of oil - ANS The sulfur content
What would cause a compressor to overload - ANS Starting under a warm evaporator load
The evaporator im a refrigeration system - ANS Absorbs heat from the product to be cooled
Moisture reacts with refrigerant and oil to form - ANS Acid
A direct expansion type evaporator is also called a - ANS Dry type evaporator
The condenser - ANS rejects the heat from the refrigerant
Positive displacement compressors have crankcase heat to - ANS Prevent the refrigerant
migration to the compressor
If the power element of a TX valve loses its charge, the___. - ANS refrigerant flow to the coil
will stop
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
, Most of the heat energy in the suction vapor entering the compressor is - ANS Latent heat
If the thermal bulb assembly develops a leak , what will occur - ANS The bulb pressure will
reduce and the valve will close
The approach of a cooling tower is the - ANS 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 - ANS Evaporator and condenser
A split phase motor can use what to energize and de-energize the start winding ? -
ANS Potential relay, current relay, and a centrifugal switch
Temperature is an indicaron of the - ANS Amount of molecular activity in the material
What can cause high suction pressures - ANS Defective compressor valves
What can cause an expansion valve to operate erratically - ANS Vapor in the liquid line, bad
compressor, low refrigerant charge.
What is a probable cause of a broken valve in the compressor - ANS Liquid slugging
If a heat pump has insufficient cooling and low suction pressure what is the cause -
ANS Partially iced coil
If the power circuit and a control circuit of a cooling system are continuous the problem is ? -
ANS A faulty compressor motor
4 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
VERIFIED ANSWERS.
What happens when room temperature soda is poured into a glass of ice ? - ANS The ice
melts because it is absorbing heat from the soda .
The compressor in a refrigeration system - ANS pumps the refrigerant throughout the system
To control ice build - up on a heat pump outdoor coil in the heating cycle a ______ is used . -
ANS 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 - ANS Dalton's Law
When moisture is present in a refrigeration system , it will react with the refrigerant and the oil
to form_ - ANS acid
A direct expansion - type evaporator is also called a - ANS dry-type evaporator
Positive displacement compressors have crankcase heat to - ANS prevent refrigerant
migration to the compressor
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
,If the power element of a TX valve loses its charge the - ANS refrigerant flow to the coil will
stop
The pressure in a refrigeration system is changed in the - ANS compressor and expansion
device
Where is cooling produced - ANS In the evaporator
Where is heat content the highest - ANS Entering the compressor
Where is heat content decreased the most ? - ANS The condenser
Where is the compressor located - ANS Between the condenser and evaporator
Where does the state of refrigerant change from liquid to a vapor - ANS The evaporator
What part of the system is pressure the lowest - ANS The evaporator
(T/F) A Compressor raises the pressure and lowers the temperature of the refrigerant -
ANS False
Rotary is what type compressor - ANS Positive displacement
If a thermal expansion valve stays closed what would be the result - ANS The valve would not
be the load and the unit will heat up
What type of metering device is used in a centrifugal chiller - ANS A high side float
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
,Which compressor require the least amount of maintenance - ANS Centrifugal
What opens the TXV - ANS 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 - ANS True
What causes oil to foam - ANS Refrigerant in the oil
What determines the corrosion tendency of oil - ANS The sulfur content
What would cause a compressor to overload - ANS Starting under a warm evaporator load
The evaporator im a refrigeration system - ANS Absorbs heat from the product to be cooled
Moisture reacts with refrigerant and oil to form - ANS Acid
A direct expansion type evaporator is also called a - ANS Dry type evaporator
The condenser - ANS rejects the heat from the refrigerant
Positive displacement compressors have crankcase heat to - ANS Prevent the refrigerant
migration to the compressor
If the power element of a TX valve loses its charge, the___. - ANS refrigerant flow to the coil
will stop
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
, Most of the heat energy in the suction vapor entering the compressor is - ANS Latent heat
If the thermal bulb assembly develops a leak , what will occur - ANS The bulb pressure will
reduce and the valve will close
The approach of a cooling tower is the - ANS 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 - ANS Evaporator and condenser
A split phase motor can use what to energize and de-energize the start winding ? -
ANS Potential relay, current relay, and a centrifugal switch
Temperature is an indicaron of the - ANS Amount of molecular activity in the material
What can cause high suction pressures - ANS Defective compressor valves
What can cause an expansion valve to operate erratically - ANS Vapor in the liquid line, bad
compressor, low refrigerant charge.
What is a probable cause of a broken valve in the compressor - ANS Liquid slugging
If a heat pump has insufficient cooling and low suction pressure what is the cause -
ANS Partially iced coil
If the power circuit and a control circuit of a cooling system are continuous the problem is ? -
ANS A faulty compressor motor
4 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
