HVAC Star Exam Questions and
Answers11
Which of the following would happen if the vent port on a gas regulator is plugged? - ANSWERS
-outlet pressure will be reduced
Two types of thermal overload relays in common use today are - ANSWERS -the bimetal relay
and the melting alloy relay.
Defrost systems can be terminated by - ANSWERS -time, pressure, and temperature
Suction gas temperature minus saturated suction temperature equals - ANSWERS -superheat
A vacuum breaker is installed between equipment and a steam trap to - ANSWERS -allow
condensate to drain after the steam has been shut off.
In order to reduce pressure to an acetylene pressure regulator, the adjusting screw is turned -
ANSWERS -counter-clockwise until the tension is off
Defective rigging components and hardware should be - ANSWERS -destroyed
Roller bearings are normally used with: - ANSWERS -Large motors operating with a heavy load.
A direct drive pump often uses a ____________ that connects the shaft of the pump motor to
the shaft of the circulator pump. - ANSWERS -brass coupling
, Name two types of bearings used in centrifugal pumps. - ANSWERS -sleeve bearings and ball
bearings
In a chiller, the refrigerant boils by ___________. - ANSWERS -absorbing heat from the water
passing through it
The four main components of a refrigeration system are - ANSWERS -compressor, condenser,
evaporator, & metering device
The difference between a contactor and a motor starter is: - ANSWERS -overload protection
If refrigerant condenses at a temperature of 105 degrees F and the water leaves the condenser
at a temperature of 95 degrees F, the ___________. - ANSWERS -condenser approach
temperature will be 10 degrees
The device that is incorporated into a vacuum steam heating system to protect the vacuum
pump from creating too low (deep) a vacuum is a: - ANSWERS -vacuum breaker
The approach temperature for the evaporator is: - ANSWERS -the difference in the refrigerant
boiling temperature and the leaving-water temperature
The rotation of a three-phase motor can be reversed by interchanging: - ANSWERS -any two
leads
Absolute zero is: - ANSWERS --460 degrees F
When a three-phase motor single-phases, it: - ANSWERS -draws power from only one phase
Answers11
Which of the following would happen if the vent port on a gas regulator is plugged? - ANSWERS
-outlet pressure will be reduced
Two types of thermal overload relays in common use today are - ANSWERS -the bimetal relay
and the melting alloy relay.
Defrost systems can be terminated by - ANSWERS -time, pressure, and temperature
Suction gas temperature minus saturated suction temperature equals - ANSWERS -superheat
A vacuum breaker is installed between equipment and a steam trap to - ANSWERS -allow
condensate to drain after the steam has been shut off.
In order to reduce pressure to an acetylene pressure regulator, the adjusting screw is turned -
ANSWERS -counter-clockwise until the tension is off
Defective rigging components and hardware should be - ANSWERS -destroyed
Roller bearings are normally used with: - ANSWERS -Large motors operating with a heavy load.
A direct drive pump often uses a ____________ that connects the shaft of the pump motor to
the shaft of the circulator pump. - ANSWERS -brass coupling
, Name two types of bearings used in centrifugal pumps. - ANSWERS -sleeve bearings and ball
bearings
In a chiller, the refrigerant boils by ___________. - ANSWERS -absorbing heat from the water
passing through it
The four main components of a refrigeration system are - ANSWERS -compressor, condenser,
evaporator, & metering device
The difference between a contactor and a motor starter is: - ANSWERS -overload protection
If refrigerant condenses at a temperature of 105 degrees F and the water leaves the condenser
at a temperature of 95 degrees F, the ___________. - ANSWERS -condenser approach
temperature will be 10 degrees
The device that is incorporated into a vacuum steam heating system to protect the vacuum
pump from creating too low (deep) a vacuum is a: - ANSWERS -vacuum breaker
The approach temperature for the evaporator is: - ANSWERS -the difference in the refrigerant
boiling temperature and the leaving-water temperature
The rotation of a three-phase motor can be reversed by interchanging: - ANSWERS -any two
leads
Absolute zero is: - ANSWERS --460 degrees F
When a three-phase motor single-phases, it: - ANSWERS -draws power from only one phase
