ESCO Air Conditioning Exam Questions and Solutions 2024, Exams of Refrigeration and Air Conditioning

Download ESCO Air Conditioning Exam Questions and Solutions 2024 and more Exams Refrigeration and Air Conditioning in PDF only on Docsity! ESCO Air Conditioning Exam Questions with All SOLUTIONS 2024 FINAL EXAM UPDATE Heat which causes a change in temperature of a substance is called - SOLUTION Sensible heat Heat added to a substance without a rise in temperature - SOLUTION Latent heat Heat added to the refrigerant in a vapor state after the evaporation process is called - SOLUTION Superheat Scroll compressor move refrigerant by - SOLUTION Involute Spirals The movement of heat by way of fluid is called - SOLUTION Convection The movement of heat by direct contact is - SOLUTION Conduction The standard unit for measuring the quantity of heat in a substance is - SOLUTION BTUs Refrigerant gives up heat when - SOLUTION It condenses Why must refrigerant in the suction line be slightly warmer than the saturation temperature? - SOLUTION Prevent liquid slugging of the compressor The state of the refrigerant in the suction line should be - SOLUTION Low pressure / Low temperature vapor The state of the refrigerant entering the condenser is - SOLUTION High pressure / Highly superheated vapor The evaporator - SOLUTION Transfers heat from the refrigerated space to the refrigerant Which of the following is not a thermodynamic property of refrigerants - SOLUTION Flammability The sequential order of steps in the vapor compressions process are - SOLUTION Compression, Condensation, Expansion, Vaporization If a 30 pound cylinder of reclaimed R 410 a refrigerant has been stored overnight at 70° the pressure in the cylinder should be approximately - SOLUTION 201 psig Fan airflow pressures are usually measured in - SOLUTION Inches of water column 0 pounds per square inch absolute is - SOLUTION A pressure which cannot be further reduced 0 pounds per square inch gauge is - SOLUTION The same as atmospheric pressure The temperature at which moisture will start to condense from the air is called - SOLUTION Dew point temperature A compound pressure gauge measures - SOLUTION Pressure and vacuum Mechanical shaft seal is necessary on a - SOLUTION Open drive compressor Liquid slugging is - SOLUTION Liquid refrigerant in the compressor clearance space The clearance space in reciprocating compressor - SOLUTION Has an effect on compressor capacity Which of the following types of air conditioning compressor is most energy- efficient - SOLUTION Scroll Which of the following represent the right order for the functions of a condenser - SOLUTION De-superheat, Condenses, Subcools A liquid receiver is used to - SOLUTION store liquid refrigerant An accumulator is used to - SOLUTION Prevent liquid refrigerant from reaching the compressor A sight glass would be normally located - SOLUTION in the liquid line before the metering device Bubbles in a sight glass would be an indication of - SOLUTION TXV with an excessive superheat setting The oil separator is installed in the - SOLUTION Discharge Line Which of the following is true of a solenoid valve in a pump down system - SOLUTION Its located before the metering device The purpose of an evaporator pressure regulating valve is to - SOLUTION prevent evaporator pressure from falling below a set limit A liquid to suction heat exchanger is often used to - SOLUTION increse liquid subcooling The oil pressure safety switch is operated by _________. - SOLUTION the difference between crankcase pressure and oil pump pressure A low pressure cut off switch is used to - SOLUTION establish a minimum operating pressure in the evaporator A partially iced over evaporator can be caused by - SOLUTION an undercharge _________ can be use for a leak detection with all high-pressure refrigerant - SOLUTION Soap bubbles The flow rate of a TXV is used in R 410A systems as compared to R22 systems is - SOLUTION Approximately 15% greater When using an electronica leak detector the sensor probe - SOLUTION should be moved at approximately 1 inch for every two seconds Moisture in a refrigeration system will cause - SOLUTION Compressor failure In order to remove as much moisture as possible from a system - SOLUTION triple evacuate the system to 500 microns with a deep vacuum pump what type of gauge is used to measure microns - SOLUTION an electronic vacuum gauge Water will vaporize at ________ temperature in a 28 in hg vacuum - SOLUTION 10°F After a system has been opened and the compressor changed the service technician must - SOLUTION Replace the filter dryer, leak check, evacuate, and charge Back seating a two-way service valve results in - SOLUTION Open service port with normal system flow The R-410 a compound gauge reads 124 psig in the suction line temperature at the condensing unit is 54°F. What is the operating system superheat - SOLUTION 12°F When topping off an operating system containing a blended refrigerant - SOLUTION introduce the refrigerant as a liquid into the low side using the throttling valve A partially clogged capillary tube can cause - SOLUTION A starved evaporator The r134a0 for a high-pressure gauge reads 146 psig in the liquid line temperature at the condensing unit is 95°F. What is the operating system subcooling - SOLUTION 15°F An overcharge of refrigerant will cause - SOLUTION 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 - SOLUTION a restriction of the return arir or a dirty evaporator A drain trap should be installed on a split system when the - SOLUTION Air handler drain is on the negative air side A customer reports that the residential split system had a compressor replaced last week by another service company. Now the unit is not cooling property. When you arrive and inspect the unit you find that the evaporator seems to be starved for refrigerant. On examining the condensing unit, you find that the liquid line is sweating where it leaves the dryer. This is most likely the result of - SOLUTION Debris from the burned out compressor has clog the dryer What is generally excepted range for evaporator airflow in CFM's per ton of residential air conditioning - SOLUTION 350 to 450 The temperature rise method for determining airflow is - SOLUTION CFM=BTU / (1.08 x delta T) What is the recommended residential indoor relative humidity for summer - SOLUTION 50% In inefficient compressor is usually indicated by ________ Head pressure and ________ Suction pressure - SOLUTION Higer than normal/ Lower than normal Which of the following is not a symptom of hermetic system that is low on refrigerant - SOLUTION High head pressure Frost on the suction line indicates - SOLUTION 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 - SOLUTION More With an automatic expansion valve, an increase in evaporator load will cause the - SOLUTION Automatic expansion valve to close