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HVAC Exam Questions and Answers, Exams of Electrical and Electronics Engineering

A comprehensive set of exam questions and answers related to hvac (heating, ventilation, and air conditioning) systems. It covers a wide range of topics, including electrical components, refrigeration principles, system design, troubleshooting, and safety practices. The questions and answers are designed to test the knowledge and understanding of hvac technicians, students, and professionals. Structured in a clear and organized manner, making it a valuable resource for preparing for hvac-related exams, assessments, or as a reference guide for ongoing professional development. The content covers fundamental hvac concepts, industry-specific terminology, and practical applications, ensuring that users can develop a strong foundation in hvac technology and best practices.

Typology: Exams

2024/2025

Available from 09/19/2024

nancy-kimani
nancy-kimani 🇬🇧

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Download HVAC Exam Questions and Answers and more Exams Electrical and Electronics Engineering in PDF only on Docsity! Nate core- Exam Questions with 100% correct Answers Honest Person - ANSWER-Is free from fraud and deception, is credible, is marked with integrity, and is fair in their dealings with others Legally binding agree - ANSWER-Must always be in writing Department of Transportation - ANSWER-Responsible for the shipping and labeling of all refrigerants Dry Bulb Temperature - ANSWER-Customers most often describe their comfort in terms of Relative humidity - ANSWER-A sling psychrometer Measures dry bulb and wet bulb temperatures which are then used to determine Refrigerant vapors in high concentration can cause - ANSWER-Heart irregularities and unconciousness Slate roofs are high risk of ... and should be avoided - ANSWER-Slipping and falling Bypass humidifier damper should be - ANSWER-Open in the winter Induction run motors is a - ANSWER-Start capacitor in series with the start winding connected by a potential relay in parallel with the start winding Capacitor run motors use a - ANSWER-Start capacitor in series with the start winding connected by a potential relay in parallel with the start winding and a permanent run capacitor connected across both start and run windings permanent split capacitor - ANSWER-Use one capacitor installed permanently across both start and run windings Motors above 5hp used on a belt drive fans are typically - ANSWER-240/460 volts 3 phase Motors can have - ANSWER-2 4 6 or 8 poles Fewer poles = - ANSWER-Faster rpms More poles = - ANSWER-Slower rpms Supply duct leaks puts the structure into - ANSWER-A negative pressure Return duct leaks puts the structure into a - ANSWER-Positive pressure Bypass humidifier damper should be what in the summer - ANSWER-Fully closed Bypass humidifier damper in the summer should be - ANSWER-Fully closed Combustion is a chemical reaction that produces - ANSWER-Light and heat Air velocity in a occupied space should be - ANSWER-25-50 feet per min If dry bulb and wet bulb temperatures are close together the humidity - ANSWER-Is high A wet cloth on the end of a thermometer will give a - ANSWER-Wet bulb reading Relative humidity is determined by - ANSWER-Wet and dry bulb temperature Lever type benders are used with - ANSWER-Soft drawn copper We bring outdoor air into conditioned space for - ANSWER-Ventilation Lower than normal voltage will - ANSWER-Increase amp draw and overheat the motor Soft copper tubing should be cut with a - ANSWER-Knife edge file Never use hacksaws to cut copper because - ANSWER-Saw chips can remain in the tubing Sling psychrometers use liquid filled thermometers because - ANSWER-They are very accurate Sensible heat ratio is - ANSWER-Sensible heat removed divided by total heat removed To set the heating anticipator you need - ANSWER-Total amperage of the furnace Btu output divided by delta t multiplied by 1.08 equals - ANSWER-Cfms for gas furnaces Motors should always run - ANSWER-Free with no bindings High superheat indicates - ANSWER-Undercharged or high heat load on the coil Under sized line sets - ANSWER-Decrease system capacity Adding refrigerant increases - ANSWER-Subcooling Low refrigerant will cause a reversing valve to - ANSWER-Not switch over The condenser fan de energizes in defrost mode to - ANSWER-Minimize defrost time Never use the word static when talking about static pressure because it is the - ANSWER-wrong terminology If a homeowner offers advice see if there is - ANSWER-merit to it Any pressure exerted on a liquid gas is measured at - ANSWER-Atmospheric pressure When climbing a ladder always - ANSWER-Face the ladder Leaking check valves on the indoor coil will - ANSWER-Flood the indoor coil Basement walls are typically - ANSWER-Load baring walls New leak detectors can detect - ANSWER-0.5 ounces a year The final step after replacing an evaporator coil is to - ANSWER-Make sure the drain pan is level When selecting a location of a condensing unit - ANSWER-Take noise into consideration Curb gaskets on roof top units - ANSWER-Prevents water leaks and reduces sound Never run the gas furnace with the heat pump on dual fuel because - ANSWER-The head pressure will increase Never energize motor windings in a - ANSWER-Vacuum A complete vacuum is - ANSWER-500 microns or below Humidifiers keep - ANSWER-Wooden floors and drywall from cracking Refrigerant vapor - ANSWER-Depletes oxygen Gas leak detectors read - ANSWER-Parts per million Materials used over trusses is called - ANSWER-Sheathing Air always moves from - ANSWER-high pressure to low pressure Economizers brings - ANSWER-Fresh air into the return Sequencers stage on the fan and a heat strip and then - ANSWER-Bring on additional heating elements Low pressure switches are used - ANSWER-For loss of charge and to protect the compressor Blower motors are - ANSWER-Forward curved centrifigal fins Thermostats need 24 volts only to - ANSWER-Power light on the thermostat Check valves allow refrigerant to - ANSWER-Bypass the metering device If static pressure decreases - ANSWER-Air flow increases A restriction or stopped up filter drier will cause a - ANSWER-Low suction pressure Sensible and latent heat is removed from - ANSWER-The condenser Vapor line condensation is a concern when going through a - ANSWER-Wall or across a ceiling When air balancing a duct systems Use - ANSWER-Selected speeds 18 gauge wire - ANSWER-The smallest wire we should use in hvac Max external static should not exceed - ANSWER-.5 inches w.c Always check the internal overload when the compressor is - ANSWER-Cool When checking for duct leaks always - ANSWER-Check the inner and outer layer of the duct Restriction or to long of a line set will cause - ANSWER-Liquid line flash gas Check voltage of the compressor at the - ANSWER-Load side of the contactor When dealing with a drafty complaint look at the - ANSWER-Supply temperature, cfms and register velocity Bent vans on a blower wheel will cause - ANSWER-Noise, loss of airflow, and motor damage Undersized suction line will cause - ANSWER-Low capacity A test of the compressor oil after a burnout indicates - ANSWER-Acidity level pressure- ANSWER-Decreases When the load on a coil decreases the suction pressureand the discharge If volts go down and amps go up and could - ANSWER-Trip an overload on a compressor A heat pump with a coil air complaint could be - ANSWER-Increased air velocities Undersized duct work causes - ANSWER-High static and high noise and low air flow To set the heat anticipator you have to have the - ANSWER-Amp draw of the complete system Drive cleats go on the side of the duct work - ANSWER-Shorter Thermal bulb would go on a TXV with a suction line of an inch or larger at - ANSWER-4 or 8 o clock If you have cfms you can figure the BTU's by - ANSWER-Cfm's x delta t x 1.08 = BTU's When bending tubing make sure the diameter of the tubing - ANSWER-Is not compromised Suction line pressure drop for r22 should be no more than - ANSWER-3psi Suction line pressure drop for r410a should be no more than - ANSWER-5psi Flux during brazing minimizes - ANSWER-Oxidation and floats dirt away A gauge pressure of 35 is an absolute pressure of 49.7 to get that - ANSWER- You add 14.7 The function of a reversing valve is to provide - ANSWER-Heating and or cooling A seven day programmable thermostat is for - ANSWER-Programming daily If heat strips are bright red it is because of - ANSWER-Low air flow 20 amp motor has a max fuse protection of - ANSWER-25 amps you can go up 25% Computed recovery brings the equipment on early to help it be at a - ANSWER-Set point at the proper time Extended plenum ductwork takes the plenum to the - ANSWER-Farthest point Low suction controls are placed in the suction line for two purposes - ANSWER-Loss of charge and to protect the compressor A nanometer is referred to as a - ANSWER-Differential pressure gauge Connecting a low side manifold hose to the discharge line of a heat pump in heat mode will result in - ANSWER-Low side gauge damage Ladder diagrams - ANSWER-Are useful for troubleshooting circumference - ANSWER-the outside perimeter of a circle Numerator - ANSWER-the top number in a fraction denominator - ANSWER-The bottom number in a fraction