NATE CORE EXAM QUESTIONS WITH A GRADED SOLUTIONS

NATE CORE EXAM QUESTIONS WITH A GRADED SOLUTIONS Pictorial wiring diagrams typically show components__ - Answer-In their approximate positions in the equipment A ladder diagram is useful for? - Answer-Troubleshooting a unit An analog VOM meter is an electrical meter that__ - Answer-Displays volts, ohms, or milliamperes on an analog scale A digital multi meter marked "auto-ranging" Will automatically set itself for__ - Answer-Reading take and range of values for all volts, amps or ohms *Using an attached diagram what purpose does PI/S I serve? - Answer-It is a multi pin connector How should a technician measure resistance with a digital ohmmeter? - Answer-Disconnect power, electrically isolate the load, and connect the leads across the load Which meter setting should a technician used to determine whether or not a set of contacts are open in an energize circuit? - Answer-Volts Why would you want to introduce fresh air into an occupied residential structure? - Answer-To create a neutral pressure within the building A ducted distribution system that is not in the Conditioned space and is well sealed on the supply side but has numerous leaks on the return side can create? - Answer-A positive pressure within the condition space What are some of the drivers that can create a negative pressure in a building? - Answer-Chimneys and exhaust fans, the duct system, and a central vacuum system For combustion to occur what three elements are necessary? - Answer-Oxygen, fuel and heat The process of combustion is? - Answer-A chemical reaction Why are humidifiers commonly used along with furnaces and heat pumps during the heating season? - Answer-To improve comfort within the occupied space by increasing the moisture content of the air Which has the greater capacity to hold moisture? - Answer-Hot air The greater difference in temperature between wet bulb and dry bulb__ - Answer-The lower the % RH Dry bulb temperature__ - Answer-•Can be read off of a common thermometer • Is the standard by which most customers rate the heating and cooling systems in their homes What are the basics of human comfort? - Answer-Temperature, relative humidity, and air velocity A joist is? - Answer-A horizontal structural member The greater the difference in temperature between wet bulb and dry bulb, the__ - Answer-Lower the % RH A stud is? - Answer-A vertical structural member A stud__ - Answer-•Is typically placed in 16" center in residential construction •Attaches the top plate and to the sole plate Material that covers the weather side of the rafters is? - Answer-Sheathing A pier and beam foundation would be used for? - Answer-A house built over a crawlspace A differential pressure gauge can? - Answer-•Read differential pressure •Read pressure relative to the atmosphere The "tool" Necessary to determine proper evacuation of a refrigeration system is? - Answer-•A compound cage set •A manifold gauge set 14.7 psia is equal to? - Answer-0 psig What is the sum of the angle of a right triangle? - Answer-180° 7 is what percent of 9? - Answer-77.77% *Solution: 7/9×100 = 77.77 Electricity is: - Answer-The flow of electrons through a conductor Voltage in and energized electrical circuit can be thought of as what? - Answer-Electrical Pressure How is current flow measured in an electrical circuit? - Answer-With an ammeter A milliampere is? - Answer-1/1000 of an ampere What happens when current flows through a conductor? - Answer-A magnetic field will be established around that conductor If the conductor is moved through a field of magnetic flux__ - Answer-A Current will be induced in that conductor In an induction transformer, the winding that receives the source voltage is called the? - Answer-Primary winding If the primary voltage on a step down transformer is 110 V and there is a 5:1 turns ratio, what is the secondary voltage? - Answer-22 V *Solution: 110/5 = 22 volts Give them a domestic hot water heater with 4500/4500 watt elements and non-simultaneous operation. What is the anticipated amp draw on an energized element one 220 V is red at that element? - Answer-20.45 Amps *Solution: I E I = P/E 4500/220 = 20.45 amps Given a 1/2 horsepower blower motor that draws 6 A and 118 V during operation. A white meter is then connected and shows a reading of 638 W. What is the power factor for this circuit? (PF = wattmeter reading v x a reading) - Answer-.90 * Solution: 6 x 118 = 708 638/708 = .09 PF = 638 watts = .90