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BOMA HVAC MASTER QBANK – Questions & Solutions
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BOMA HVAC MASTER QBANK – Questions & Solutions
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BOMA HVAC MASTER QBANK – Questions & SolutionsThe man whose work is considered the real beginning of the science of air-
conditioning _____. Correct Ans - Willis Carrier
Psychrometry refers to the relationship between _____ and _____. Correct Ans - Humidity; air
The amount of moisture in the air compared to how much it can hold is _____. Correct Ans - Relative humidity
The human bodies well-being depends upon the _____. Correct Ans - Body's metabolism
The device used to determine the moisture content of air is the _____ Correct Ans - psychrometer
Of the fuels listed the one that is the most efficient is _____. Correct Ans - Gas
The effective temperature takes into consideration the effect of _____ and _____. Correct Ans - Humidity; temperature
Air conditioning is the control of the _____, _____, _____ and _____. Correct Ans - Temperature, humidity, purity and distribution of air.
The element that makes up the greatest percentage by volume of air is _____. Correct Ans - Nitrogen
Steam gives off a great amount of heat because of its _____. Correct Ans - Specific heat
The velocity of air moving thru a fan system is expressed in _____. Correct Ans - Feet per minute
What volume of air will move thru a duct 24x18 at velocity of 450 feet per minute? Correct Ans - 1350 cfm The following types of fans are classified as centrifugal fans. Correct Ans - Forward curved, radial and backward curved
Select the statement that does not apply to backward inclined (Non overloading) fans. Correct Ans - Has an overloading (BHP) horse power curve.
The quantity of air moving thru a fan system is expressed in _____. Correct Ans - Cubic feet per minute
The instrument used to measure air pressure in duct is the _____. Correct Ans - Monometer
Air flow thru a duct has the highest _____. Correct Ans - Velocity near the center of the duct.
Select the statement which does not apply to the fan laws. Correct Ans - Static pressure in a duct increases as the velocity decreases
Variable air volume system feature is _____. Correct Ans - Varies the volume of air with space temperature conditions
Double duct systems are _____. Correct Ans - Used in multi-room buildings having variable heat loads
The purpose of a primary control is to _____. Correct Ans - Start or stop the system
A pressure stat responds to _____. Correct Ans - System pressure
The oil safety switch is operated by _____. Oil pressure Correct Ans - A low limit control _____. Correct Ans - Provides for safe cutoff of the system.
A high limit control _____. Correct Ans - Provides for safe cutoff of the system
Limit controls _____. Correct Ans - Are wired into the circuit in series A diluting switch is used to _____. Correct Ans - Change proportional action to two position control.
A proportional control: Correct Ans - Where a movement from the set point produces a proportional movement of the actuator
A three way diverting valve: Correct Ans - has two outlets and one common inlet
Heat will continue to flow between two bodies until they have the same amount of _____. Correct Ans - Sensible heat
Heat which causes a change of state is _____. Correct Ans - Latent heat
The refrigeration effect of a refrigerant is improved by _____. Correct Ans -
Subcooling the liquid.
In the refrigeration cycle, the medium that picks up the heat is the _____. Correct Ans - refrigerant.
A heat exchanger _____. Correct Ans - Sub cools the liquid refrigerant
Calculations involving heat load of people takes into consideration heat due to
_____ and _____. Correct Ans - Latent heat; sensible heat
The flow control device used to maintain system temperature is the _____. Correct Ans - Evaporator pressure valve
Enthalpy refers to the _____. Correct Ans - Heat content of the refrigerant
The metering device is designed to _____. Correct Ans - Control flow of refrigerant
The evaporator pressure regulator (EPR). Correct Ans - Limits evaporator pressure Assume a centrifugal unit with R11 is operating at 8.8 PSIG condensing pressure and 86 degrees condensing temperature, what is the partial pressure
due to air? Correct Ans - 5.6 (see chart) (insert picture)
Utilizing the values in the above problem, what is the partial pressure due to the refrigerant? Correct Ans - 3.2 (see chart)(insert picture)
The most efficient method of capacity control is by the use of _____. Correct
Ans - Speed control
The pump out unit: Correct Ans - is used to transfer the refrigerant to an external receiver.
The movement of the pre-rotation vanes is controlled by the _____. Correct Ans - Chill water temperature control.
The function of the economizer is to _____. Correct Ans - Increase the refrigeration effect.
Economizers: Correct Ans - for the same power input, capacity is increased
The least likely cause at high suction pressure would be _____. Correct Ans - Not enough system load
A psychometric chart is a graphic representation of _____? Correct Ans - Thermodynamic properties
Enthalpy refers to the _____? Correct Ans - Measure of energy content of a
substance
What is an excellent heat carrier because it _____? Correct Ans - Has high specific heat
The element that makes up the most percentage of air is _____? Correct Ans
- Nitrogen
Air flows through a duct has the most _____? Correct Ans - Velocity near the center of the duct
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