Air Conditioning Certification exam with 100% correct answers 2024

sensible heat - answer-Heat that causes change in temperature of a substance latent heat - answer-Heat that is added with out a rise in temperature super heat - answer-Heat added to refrigerant in vapor state after evaporation process is involute spirals - answer-Scroll compressor moves refrigerant by means of convection - answer-movement of heat by way of fluid or air conduction - answer-movement of heat by way of solid BTU - answer-Standard unit for measuring heat Condensor - answer-refrigerant gives up heat in the liquid slugging - answer-refrigerant in suction line must be slightly warmer than the saturation temperature to prevent low - answer-state of refrigerant in the suction line is ____ pressure _____ temp vapor High - answer-state of refrigerant entering the condensor would be ______ pressure ______ superheated vapor evaporator - answer-transfers heat from refrigerated space to the refrigerant flammability - answer-which is not a thermo-dynamic property of refrigerants Compression, condensation, expansion and vaporization - answer-the sequential order of steps in vapor-compression process 201 psig - answer-30 lbs cylinder of R410A sits overnight at 70 degrees would have a pressure of inches of water column (WC) - answer-fan airflow pressures are usually measured in 0 psia - answer-pressure that cannot be further reduced 0 psig - answer-the same as atmospheric pressure dew point temp - answer-the temp at which moisture will start to condense from the air is the pressure and vacuum - answer-compound pressure gauge measures open drive compressor - answer-a mechanical shaft seal is necessary on an liquid slugging - answer-liquid refrigerant in the compressor clearance space clearance space - answer-has an effect on compressor capacity in a reciprocating compressor scroll - answer-which type of air conditioning compressor is the most effecient De-superheat, condense and subcool - answer-what is the right order of function in a condensor air cooled, water cooled and evaporative - answer-3 basic types of condensors sensible and latent - answer-heat removed from refrigerant by condensor is both _____ and ______ energy recovery ventilator - answer-what uses an air to air heat exchanger to recover heat 30 degrees hotter than the air entering - answer-when testing the efficiency of an air cooled condenser the refrigerant condensing temp should be approximately 10 degrees hotter than the air entering - answer-When testing efficiency of a water cooled condenser the refrigerant condensing temp should be approximately de-superheat - answer-First function of a condensor is to ____________________ before condensing can occur TXV - answer-A _______ is designed to maintain constant superheat Auto Expansion Valve - answer-______ ______________ _________ maintains constant evaporative pressure evaporative, spring, sensor bulb - answer-Thermo Expansion valve (TXV) has 3 pressures _____________________, _________________, and ___________________ lower than valve body - answer-When mounting TXV sensor bulb, you do not install it _________________________________________________ . warmer - answer-In an air conditioning system that uses TXV, the temp of the evaporator outlet will usually be ______________ than evaporator inlet fairly constant - answer-Auto expansion valve (AXV) is best suited when the system load remains ___________ ______________. evaporator temp - answer-Capillary tubes do not maintain constant _________________________________ . close - answer-A decrease in superheat causes the TXV to begin to ___________. close - answer-A rise in evaporator pressure causes AXV to ___________. NTC Thermistor - answer-A thermal electric (solid state) expansion valve is controlled by _______ _______________. mixture of liquid and flash gas - answer-In a direct expansion evaporative system, the refrigerant enters the evaporator as a ________________________________________________________ . coil to the condensing unit and latent/sensible load - answer-Most important consideration in evaporator coil selection is to match the _______________________________________________ evaporator - answer-In the ______________________ latent heat is transferred from refrigerated space to the refrigerant. condensor and metering device - answer-The liquid line filter dryer should be placed between the____________________________________________ . sub-cooling - answer-The only way to minimize flash gas is by ____________________ the liquid refrigerant. Liquid receiver - answer-______________ _______________ is used to store the liquid refrigerant. Accumulator - answer-The ________________________ keeps liquid from getting to the compressor Site glass - answer-_______ __________ is located in the liquid line before the metering device bubbles in sight glass - answer-_____________________________________ indicate refrigerant blend with a high temp glide discharge line - answer-Oil separator is installed in the ______________ ______. metering device - answer-A solenoid valve pump in a down system is located before the ____________ _____________. Keep pressure from falling below limit - answer-The purpose of the evaporator pressure regulating valve is to ___________________________________________________. liquid sub-cooling - answer-A liquid-to-suction heat exchanger is often used to increase ___________ _________________. Oil pressure safety switch - answer-______ ____________ __________ __________ is opporated by the difference between crank case pressure and oil pressure. Low - answer-_______ pressure cut off switch is used to establish a minimum opporating pressure undercharge - answer-Partially iced over evaporator coil can be caused by an ___________________________. soap bubbles - answer-_________ ____________ can be used for leak detection with all high pressure systems 40-70% - answer-The flow rate of a R410A system is ___________ higher than that of R22 1 in - answer-An electronic leak detector should be used at ___________ every 2 seconds 100 degrees - answer-10 lbs. of refrigerant passing through a water cooled condenser will lose 20 Btu's of heat per lb. if 10 lbs of water passes through the condenser with an entering temp of 80 degrees. The temp. of the water leaving the condenser is stopped up filter drier - answer-a temperature differential across a filter drier indicates a compressor failure - answer-Moisture in a refrigeration system will cause _____________ _____________ Electronic vacuum gauge - answer-_____________ _____________ __________ will measure microns 100 - answer-Water will vaporize at ___________ degrees F in a 28 in vacuum Replace filter dryer, leak check, evacuate, charge - answer-After a system has been opened and the compressor changed _____________________________, _____________, _______________________, and _______________. 500 microns - answer-To remove as much moisture as possible from a system, triple evacuate the system to _______ ____________ 124 psig - answer-R134A vapor enters the condenser at 124 psig, 100 degrees Fahrenheit it leaves the condenser at 80 degrees fahrenheit its pressure will be approximately compressor - answer-it is desirable for refrigerant in the suction line to be slightly superheated in order to insure liquid refrigerant does not enter high discharge line pressure and low liquid line pressure - answer-What would be indicative of an oil logged condenser 12 - answer-A 410A system has compound gauge reading of 54 degrees F at 124 psig, the super heat would be _______ degrees F. liquid into low side - answer-When topping off an operating system using a blended refrigerant, introduce ________________________________________ while throttling the valve. starved evaporator - answer-Partially clogged capillary tube can cause_____________ _____________. 15 - answer-R134A high pressure gauge reads 146 psig and the liquid line temp at condensing unit is 95 degrees, the sub-cooling is _______ degrees F. Increased head pressure - answer-Overcharged refrigerant will cause an ____________ ______ ______________ dirty evaporator - answer-Complaints that the air system runs constantly but there is no cooling would be ___________ __________________ negative - answer-Drain trap should be installed on split system when air handler drain is on _______________ side of evaporator. debris in filter dryer - answer-If liquid line is sweating there is _____________________________________ . 350-450 - answer-Generally accepted range for evaporator airflow CFM per ton is __________________________ CFM CFM - answer-BTU/1.08x DeltaT CFM - answer-Cubic feet per minute______________ CFM - answer-Temp rise method for determining air flow is _________ 50 - answer-Recommended residential indoor relative humidity for summer is _____ % lower higher - answer-An inefficient compressor is indicated by __________ than normal head pressure _________ than normal suction pressure high head pressure - answer-A hermetic system that is low on refrigerant will not have 32 - answer-Frost on suction line indicates it's below dewpoint temp and below ______ degrees F More - answer-Increase in head pressure causes _______ refrigerant to flow through capillary tube. Valve - answer-With auto expansion valve an increase in evaporator load will cause the _________ to close Low head pressure - answer-When a TEV or capillary tube is used as a metering device low refrigerant charge will cause _________ ____________ __________________. 15 - answer-Max oporating pressure setting for an acetylene torch is _____ psig 45 - answer-When connecting copper to steel braise with ______ % silver alloy flushing filter dryers - answer-Solid contaminants from a hermetic compressor burnout are best removed by _____________ the system and installing _______ /_______ in both the liquid and suction lines reduce - answer-If the cut off plate is removed from blower assembly, it will ___________ air flow Inert gas - answer-Can use a trace amount of refrigerant and __________ ______ to leak test the system low - answer-After properly recharging a system, if the compressor is noisy, it is _____ on oil inefficient - answer-Over sized air conditioning system can cause _________________ de-humidification of the space low - answer-Low operating pressure and low system amperage draw causes _______ air flow across the evaporator high - answer-Air or other non-condensables will cause ______ suction line and ________ discharge line pressure high - answer-Refrigerant overcharge will cause _______ suction and _______discharge pressure high low - answer-Compressor with broken reed valve causes _______ suction and ________ discharge pressure low - answer-Low refrigerant in the system causes _______ suction and ________ discharge high higher - answer-A TEV sensing bulb which becomes detached from the suction line will cause ______ suction and _____________ than normal discharge pressure. high - answer-A faulty condenser fan motor will cause ________ suction line and ___________ discharge line pressure. Low - answer-A dirty evaporator causes _______ suction line and _______ discharge line pressure. must be recovered using approved equipment - answer-before a vapor/compression system is opened for service electric resistive heat air handler - answer-the temperature rise method of determining air volume can be used on 3 inches - answer-what is the min. vertical drop from the outlet of the condensate drain pan to the inlet of the P trap closed normal - answer-Back seating a 2 way service valve results in a _________ service port with a ____________ system flow