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2025-2026 ESCO AIR CONDITIONING EXAM|ORIGINAL 100Qs&As|ALREADY GRADED A+
Typology: Exams
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Heat which causes a change in temperature of a substance is called Sensible heat Heat added to a substance without a rise in temperature Latent heat Heat added to the refrigerant in a vapor state after the evaporation process is called Superheat Scroll compressor move refrigerant by Involute Spirals The movement of heat by way of fluid is called Convection The movement of heat by direct contact is Conduction
The standard unit for measuring the quantity of heat in a substance is BTUs Refrigerant gives up heat when It condenses Why must refrigerant in the suction line be slightly warmer than the saturation temperature? Prevent liquid slugging of the compressor The state of the refrigerant in the suction line should be Low pressure / Low temperature vapor The state of the refrigerant entering the condenser is High pressure / Highly superheated vapor The evaporator Transfers heat from the refrigerated space to the refrigerant
The temperature at which moisture will start to condense from the air is called Dew point temperature A compound pressure gauge measures Pressure and vacuum Mechanical shaft seal is necessary on a Open drive compressor Liquid slugging is Liquid refrigerant in the compressor clearance space The clearance space in reciprocating compressor Has an effect on compressor capacity Which of the following types of air conditioning compressor is most energy- efficient Scroll
Which of the following represent the right order for the functions of a condenser De-superheat, Condenses, Subcools Refrigerant R 134a vapor enters the condenser at 124 psi G, 100°F. it leaves as a liquid from the condenser subcooled 20°F and the pressure will be approximately 87 psig There are three basic types of condensers, air-cooled, water-cooled and the _____________ cooled 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 80°F the temperature of the water leaving the condenser is 100°F The heat removed from the refrigerant by the condenser is Both sensible and latent heat.
The automatic expansion valve is designed to maintain Constant evaporator pressure The thermostatic expansion valve has three operating pressures Evaporator pressure, Spring pressure, and Sensor bulb pressure When mounting a thermostatic expansion valve sensor bulb, which of the following is not true It must be installed lower than the valve body In an air conditioning system that uses a thermostatic expansion valve, the temperature of the evaporator outlet will usually be Warmer than the evaporator inlet In automatic expansion valve is best suited When the system load remains fairly constant Which of the following is not true of a capillary tube metering device
They maintain a constant evaporator temperature A decrease in superheat causes the thermostatic expansion valve to begin to Close A rise in evaporator pressure causes the automatic expansion valve to begin to Close A thermal electric expansion valve is controlled by NTC thermistor In a direct expansion evaporator system, the refrigerant enters the evaporator as 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 Condensing unit and the latent/sensible loads
Bubbles in a sight glass would be an indication of TXV with an excessive superheat setting The oil separator is installed in the Discharge Line Which of the following is true of a solenoid valve in a pump down system Its located before the metering device The purpose of an evaporator pressure regulating valve is to prevent evaporator pressure from falling below a set limit A liquid to suction heat exchanger is often used to increse liquid subcooling The oil pressure safety switch is operated by _________. the difference between crankcase pressure and oil pump pressure
A low pressure cut off switch is used to establish a minimum operating pressure in the evaporator A partially iced over evaporator can be caused by an undercharge _________ can be use for a leak detection with all high-pressure refrigerant Soap bubbles The flow rate of a TXV is used in R 410A systems as compared to R22 systems is Approximately 15% greater When using an electronica leak detector the sensor probe should be moved at approximately 1 inch for every two seconds Moisture in a refrigeration system will cause
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 12°F When topping off an operating system containing a blended refrigerant introduce the refrigerant as a liquid into the low side using the throttling valve A partially clogged capillary tube can cause 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 15°F An overcharge of refrigerant will cause 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 a restriction of the return arir or a dirty evaporator A drain trap should be installed on a split system when the 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 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 350 to 450 The temperature rise method for determining airflow is CFM=BTU / (1.08 x delta T)
With an automatic expansion valve, an increase in evaporator load will cause the Automatic expansion valve to close When a TEV or capillary tube is used as a metering device a low refrigerant charge will cause Low head pressure What is the maximum operating pressure setting for an acetylene torch 15 psig When connecting copper to steal the recommended brazing filler alloy is 45% silver alloy Solid contaminants such as sludge and carbon from a severe hermetic compressor motor burn out are best removed 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
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 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 Low oil in the system And air-conditioning system that is oversized can cause Inefficient dehumidification of the condition space While troubleshooting a residential split system the service technician find slow operating pressures in los system amperage draw. This could be an indication of Low airflow across the evaporator
High suction pressure and high discharge pressure A dirty evaporator in an air conditioning system will cause the symptoms Low suction pressure and low discharge pressure
