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ESCO Air Conditioning Exam Questions &
100% Verified Answers | Latest Update | Already
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Heat which causes a change in temperature of a substance is called ๐ธ๐ธ๐ธ : Sensible heat Heat added to a substance without a rise in temperature ๐ธ๐ธ๐ธ : Latent heat Heat added to the refrigerant in a vapor state after the evaporation process is called ๐ธ๐ธ๐ธ : Superheat Scroll compressor move refrigerant by ๐ธ๐ธ๐ธ : Involute Spirals The movement of heat by way of fluid is called ๐ธ๐ธ๐ธ : Convection The movement of heat by direct contact is ๐ธ๐ธ๐ธ : Conduction
The standard unit for measuring the quantity of heat in a substance is ๐ธ๐ธ๐ธ : BTUs Refrigerant gives up heat when ๐ธ๐ธ๐ธ : It condenses Why must refrigerant in the suction line be slightly warmer than the saturation temperature? ๐ธ๐ธ๐ธ : Prevent liquid slugging of the compressor The state of the refrigerant in the suction line should be ๐ธ๐ธ๐ธ : Low pressure / Low temperature vapor The state of the refrigerant entering the condenser is ๐ธ๐ธ๐ธ : High pressure / Highly superheated vapor The evaporator ๐ธ๐ธ๐ธ : Transfers heat from the refrigerated space to the refrigerant Which of the following is not a thermodynamic property of refrigerants ๐ธ๐ธ๐ธ : Flammability
Mechanical shaft seal is necessary on a ๐ธ๐ธ๐ธ : Open drive compressor Liquid slugging is ๐ธ๐ธ๐ธ : Liquid refrigerant in the compressor clearance space The clearance space in reciprocating compressor ๐ธ๐ธ๐ธ : Has an effect on compressor capacity Which of the following types of air conditioning compressor is most energy-efficient ๐ธ๐ธ๐ธ : Scroll Which of the following represent the right order for the functions of a condenser ๐ธ๐ธ๐ธ : De-superheat, Condenses, Subcools Refrigerant R 134a vapor enters the condenser at 124 psi G, 100ยฐF. it leaves as a liquid from the condenser subcooled 20ยฐF and the pressure will be approximately ๐ธ๐ธ๐ธ : 87 psig There are three basic types of condensers, air-cooled, water-cooled and the _____________ cooled
๐ธ๐ธ๐ธ : Evaporative 10 pounds of refrigerant passing through a water cooled condenser will lose 20 BTUs of heat per pound. If 10 pounds of water passes through the condenser with an entering temperature of 80ยฐF the temperature of the water leaving the condenser is ๐ธ๐ธ๐ธ : 100ยฐF The heat removed from the refrigerant by the condenser is ๐ธ๐ธ๐ธ : Both sensible and latent heat. An energy recovery ventilator is ๐ธ๐ธ๐ธ : an air to air heat exchanger to recover heat When testing the efficiency of an air-cooled condenser, the refrigerant condensing temperature should be approximately ________ higher than the entering air temperature ๐ธ๐ธ๐ธ : 30ยฐF When testing the efficiency of a water-cooled condenser, the refrigerant condensing temperature should be approximately _________ higher than the leaving water temperature ๐ธ๐ธ๐ธ : 10ยฐF
Which of the following is not true of a capillary tube metering device ๐ธ๐ธ๐ธ : They maintain a constant evaporator temperature A decrease in superheat causes the thermostatic expansion valve to begin to ๐ธ๐ธ๐ธ : Close A rise in evaporator pressure causes the automatic expansion valve to begin to ๐ธ๐ธ๐ธ : Close A thermal electric expansion valve is controlled by ๐ธ๐ธ๐ธ : NTC thermistor In a direct expansion evaporator system, the refrigerant enters the evaporator as ๐ธ๐ธ๐ธ : A mixture of liquid with some "flash-gas" Which of the following is the most important consideration in the selection of an evaporator coil. Match the coil to the ๐ธ๐ธ๐ธ : Condensing unit and the latent/sensible loads In the evaporator ๐ธ๐ธ๐ธ : Latent heat is transferred from the refrigerated space to the refrigerant
A liquid line filter-drier should be placed between the ๐ธ๐ธ๐ธ : Condenser and the Metering device The only way to minimize flash gas is by ๐ธ๐ธ๐ธ : Sub-cooling the liquid refrigerant entering the metering device closer to the evaporator temperature A liquid receiver is used to ๐ธ๐ธ๐ธ : store liquid refrigerant An accumulator is used to ๐ธ๐ธ๐ธ : Prevent liquid refrigerant from reaching the compressor A sight glass would be normally located ๐ธ๐ธ๐ธ : in the liquid line before the metering device Bubbles in a sight glass would be an indication of ๐ธ๐ธ๐ธ : TXV with an excessive superheat setting The oil separator is installed in the ๐ธ๐ธ๐ธ : Discharge Line
The flow rate of a TXV is used in R 410A systems as compared to R22 systems is ๐ธ๐ธ๐ธ : Approximately 15% greater When using an electronica leak detector the sensor probe ๐ธ๐ธ๐ธ : should be moved at approximately 1 inch for every two seconds Moisture in a refrigeration system will cause ๐ธ๐ธ๐ธ : Compressor failure In order to remove as much moisture as possible from a system ๐ธ๐ธ๐ธ : triple evacuate the system to 500 microns with a deep vacuum pump what type of gauge is used to measure microns ๐ธ๐ธ๐ธ : an electronic vacuum gauge Water will vaporize at ________ temperature in a 28 in hg vacuum ๐ธ๐ธ๐ธ : 10ยฐF After a system has been opened and the compressor changed the service technician must ๐ธ๐ธ๐ธ : Replace the filter dryer, leak check, evacuate, and charge
Back seating a two-way service valve results in ๐ธ๐ธ๐ธ : Open service port with normal system flow The R- 41 0 a compound gauge reads 124 psig in the suction line temperature at the condensing unit is 54ยฐF. What is the operating system superheat ๐ธ๐ธ๐ธ : 12ยฐF When topping off an operating system containing a blended refrigerant ๐ธ๐ธ๐ธ : introduce the refrigerant as a liquid into the low side using the throttling valve A partially clogged capillary tube can cause ๐ธ๐ธ๐ธ : A starved evaporator The r134a0 for a high-pressure gauge reads 146 psig in the liquid line temperature at the condensing unit is 95ยฐF. What is the operating system subcooling ๐ธ๐ธ๐ธ : 15ยฐF An overcharge of refrigerant will cause ๐ธ๐ธ๐ธ : increased head pressure A customer complains that their air conditioning system is running constantly, but no cooling enough. The suction line is very cold in the compressor is sweating. The most likely cause is
In inefficient compressor is usually indicated by ________ Head pressure and ________ Suction pressure ๐ธ๐ธ๐ธ : Higer than normal/ Lower than normal Which of the following is not a symptom of hermetic system that is low on refrigerant ๐ธ๐ธ๐ธ : High head pressure Frost on the suction line indicates ๐ธ๐ธ๐ธ : That its temperature is below the dew point and its below 32 degrees An increase in head pressure causes___refrigerant to flow through a capillary tube ๐ธ๐ธ๐ธ : More With an automatic expansion valve, an increase in evaporator load will cause the ๐ธ๐ธ๐ธ : Automatic expansion valve to close When a TEV or capillary tube is used as a metering device a low refrigerant charge will cause ๐ธ๐ธ๐ธ : Low head pressure What is the maximum operating pressure setting for an acetylene torch ๐ธ๐ธ๐ธ : 15 psig
When connecting copper to steal the recommended brazing filler alloy is ๐ธ๐ธ๐ธ : 45% silver alloy Solid contaminants such as sludge and carbon from a severe hermetic compressor motor burn out are best removed ๐ธ๐ธ๐ธ : By flushing the system and then installing filter dryers in both the liquid and suction lines If the cut off play is removed from the blower assembly how will this affect blower performance ๐ธ๐ธ๐ธ : It would reduce airflow At a residential service call no cooling complaint, the service technician finds the unit to be completely out of refrigerant. The technician decides to use a trace amount of refrigerant and___in order to pressurize the system ๐ธ๐ธ๐ธ : Inert gas A technician has found an air-conditioning system with a leak in the liquid line. After the line is repaired the system is evacuated in properly recharged. When the system restarted the compressor is noisy and running hot. The most probable cause of the noise is ๐ธ๐ธ๐ธ : Low oil in the system
A TEV sensing bulb which becomes detached from the suction line will cause the symptoms ๐ธ๐ธ๐ธ : High suction pressure and lower than normal discharge pressure A faulty condenser fan motor on an air conditioning system will cause the symptoms ๐ธ๐ธ๐ธ : High suction pressure and high discharge pressure A dirty evaporator in an air conditioning system will cause the symptoms ๐ธ๐ธ๐ธ : Low suction pressure and low discharge pressure
