BOMA-HVAC Questions And Answers With Complete Solutions Rated A+

The man whose work is considered the real beginning of the science of air-conditioning _____. - CORRECT ANSWER-Willis Carrier Psychrometry refers to the relationship between _____ and _____. - CORRECT ANSWER-Humidity; air The amount of moisture in the air compared to how much it can hold is _____. - CORRECT ANSWER-Relative humidity The human bodies well being depends upon the _____. - CORRECT ANSWER-Bodies metabolism The device used to determine the moisture content of air is the _____ - CORRECT ANSWER-psychrometer Of the fuels listed the one that is the most efficient is _____. - CORRECT ANSWER-Gas The effective temperature takes into consideration the effect of _____ and _____. - CORRECT ANSWER-Humidity; temperature Air conditioning is the control of the _____, _____, _____ and _____. - CORRECT ANSWER-Temperature, humidity, purity and distribution of air. The element that makes up the greatest percentage by volume of air is _____. - CORRECT ANSWER-Nitrogen Steam gives off a great amount of heat because of its _____. - CORRECT ANSWER-Specific heat The velocity of air moving thru a fan system is expressed in _____. - CORRECT ANSWER-Feet per minute What volume of air will move thru a duct 24x18 at velocity of 450 feet per minute? - CORRECT ANSWER-1350 cfm The following types of fans are classified as centrifugal fans. - CORRECT ANSWER-Forward curved, radial and backward curved Select the statement that does not apply to backward inclined fans. - CORRECT ANSWER-Has an overloading BHP horse power curve. The quantity of air moving thru a fan system is expressed in _____. - CORRECT ANSWER-Cubic feet per minute The instrument used to measure air pressure in duct is the _____. - CORRECT ANSWER-Monometer Air flow thru a duct has the highest _____. - CORRECT ANSWER-Velocity near the center of the duct. Select the statement which does not apply to the fan laws. - CORRECT ANSWER-Static pressure in a duct increases as the velocity decreases. Variable air volume system feature is _____. - CORRECT ANSWER-Varies the volume of air with space temperature conditions Double duct systems are _____. - CORRECT ANSWER-? The purpose of a primary control is to _____. - CORRECT ANSWER-Start or stop the system A pressurestat responds to _____. - CORRECT ANSWER-System pressure The oil safety switch is operated by _____. Oil pressure - CORRECT ANSWER- A low limit control _____. - CORRECT ANSWER-? A high limit control _____. - CORRECT ANSWER-? Limit controls _____. - CORRECT ANSWER-Are wired into the circuit in series A diulating switch is used to _____. - CORRECT ANSWER-Change proportional action to two position control. A ratio relay is used to _____. - CORRECT ANSWER-Provide sequence control of more than one actuator. A proportional control: - CORRECT ANSWER-Where a movement from the set point produces a proportional movement of the actuator A three way diverting valve: - CORRECT ANSWER-has two outlets and one common inlet Heat will continue to flow between two bodies until they have the same amount of _____. - CORRECT ANSWER-Sensible heat Heat which causes a change of state is _____. - CORRECT ANSWER-Latent heat The refrigeration effect of a refrigerant is improved by _____. - CORRECT ANSWER-Subcooling the liquid. In the refrigeration cycle, the medium that picks up the heat is the _____. - CORRECT ANSWER-refrigerant. A heat exchanger _____. - CORRECT ANSWER-Subcools the liquid refrigerant Calculations involving heat load of people takes into consideration heat due to _____ and _____. - CORRECT ANSWER-Latent heat; sensible heat The flow control device used to maintain system temperature is the _____. - CORRECT ANSWER-Evaporator pressure valve Enthalpy refers to the _____. - CORRECT ANSWER-Heat content of the refrigerant The metering device is designed to _____. - CORRECT ANSWER-Control flow of refrigerant The evaporator pressure regulator (EPR). - CORRECT ANSWER-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 ANSWER-5.6 (see chart) Utilizing the values in the above problem, what is the partial pressure due to the refrigerant? - CORRECT ANSWER-3.2 (see chart) The most efficient method of capacity control is by the use of _____. - CORRECT ANSWER-Speed control The pump out unit: - CORRECT ANSWER-is used to transfer the refrigerant to an external receiver. The movement of the pre-rotation vanes is controlled