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HVAC Air Conditioning Esco Questions and Answers, Exams of Refrigeration and Air Conditioning

A comprehensive set of questions and answers related to hvac air conditioning systems. It covers various aspects of hvac, including refrigerant properties, compressor types, condenser and evaporator functions, metering devices, and troubleshooting techniques. Suitable for students and professionals seeking to enhance their understanding of hvac principles and practices.

Typology: Exams

2024/2025

Available from 02/20/2025

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HVAC Air Condition Esco Questions & 100%
Verified Answers | Latest Update | Already
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Heat which causes a change in temperature of a substance is called
๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ: Sensible Heat
Heat added to a substance without a rise in temperature is called
๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ: Latent Heat
Heat added to refrigerant in a vapor state after the evaporation process is called
๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ: Superheat
A scroll compressor moved refrigerant by means of
๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ: Involute spirals
The movement of heat by way of fluid is called
๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ: Convection
The movement of heat through a solid object is called
๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ: Conduction
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HVAC Air Condition Esco Questions & 100%

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Heat which causes a change in temperature of a substance is called ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Sensible Heat Heat added to a substance without a rise in temperature is called ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Latent Heat Heat added to refrigerant in a vapor state after the evaporation process is called ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Superheat A scroll compressor moved refrigerant by means of ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Involute spirals The movement of heat by way of fluid is called ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Convection The movement of heat through a solid object is called ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Conduction

The standard unit for measuring the quantity of heat in a substance ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : British Thermal Unit A refrigerant gives up heat when it ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Condenses Why must refrigerant in the suction line be slightly warmer than the saturation temperature? ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Prevent liquid slugging of compressor It is desirable for refrigerant in the suction line to be slightly superheated in order to ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Insure liquid refrigerant does not enter the compressor A mechanical shaft seal is necessary on ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Semi-hermetic compressor Liquid slugging is ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Liquid refrigerant in the compressor clearance space The clearance space in a reciprocating compressor ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Varies depending on compressor speed

๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : An air to air heat exchanger to recover heat Which of the following can NOT be used as a low ambient temperature control? ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Crankcase regulating valves The state of refrigeration in the suction line should be ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Low pressure/ low temperature vapor The state of refrigerant entering the condenser is ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : High pressure/ highly superheated vapor The evaporator ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Transfers heat from the refrigerated space to the refrigerant Which of the following is not a thermodynamic property of refrigerant ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Flammability The sequential order of steps in the vapor-compression process are ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Compression, condensation, expansion, vaporization If a 30 pound container of R-410A refrigerant has been stored over night at 70ยฐF, the pressure in the cylinder should be approximately

๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : 201 psig Fan airflow pressures are usually measured in ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Inches of water column (WC) Zero psig is ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : The same as atmospheric pressure The temperature at which moisture will start to condense from the air is ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Dew point temperature A compound pressure gauge measures ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Pressure and vacuum When testing the efficiency of an air cooled condenser, the refrigerant condensing temperature should be no more than ______ higher than the entering air temperature ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : 30ยฐf When testing the efficiency of a water cooled condenser, the refrigerant condensing temperature should be approximately _______ higher than the entering air temperature ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : 10ยฐf

A decrease in superheat causes the thermostatic expansion valve begins to ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Close A rise in evaporator pressure causes the automatic expansion valve to begin to ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Close A thermal-electric (solid state) expansion valve is controlled by ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : NTC Thermistor In a direct expansion (DX) evaporator system, the refrigerant enters the evaporator as ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Mixture of liquid with some flash gas In the evaporator ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Latent heat is transferred from the refrigerated space to the refrigerant A liquid line filter drier should be placed between the ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Condenser and metering device The only way to minimize flash gas is by ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Sub-cooling the liquid refrigerant entering the metering device closer to the evaporator temperature

A liquid receiver is used to ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Store liquid refrigerant An accumulator is used to ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Prevent liquid refrigerant from reaching the compressor A sight glass would normally be located ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : In the liquid line, before the metering device Bubbles in the sight glass could be an indication of ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Low compressor capacity The oil separator is installed in the ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Discharge line Which of the following is true of a solenoid valve in a pump down system ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : It is located before the metering device The purpose of an evaporator pressure regulating valve is to ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Prevent evaporator pressure from falling

๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Compressor failure In order to remove as much moisture as from a system ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Triple evacuate the system to 500 microns with a deep vacuum pump What kind of gauge is used to measure microns ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : An electronic vacuum gauge Water will vaporize at _______ temperature in a 28 in hg vacuum ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : 208 degrees F After a system has been opened and the compressor changed, the service technician must ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Replace the filter drier, leak check, evacuate, and charge Back seating a two way solenoid valve results in ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Closed service port with normal system flow Before vapor/ compression system is opened for service ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : The refrigerant must be recovered using approved equipment

The R410A compound gauge reads 124 psig and the suction line temperature at the condensing unit is 54ยฐf. What is the operating superheat? ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : 11ยฐF When topping off an operating system containing a blended refrigerant ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Introduce the refrigerant as a liquid into the low side using a throttle valve A partially clogged capillary tube metering device can cause ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : A starved evaporator The R134a high pressure gauge reads 146 psig and the liquid line temperature at the condensing unit is 95ยฐf what is the operating subcooling? ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : 15ยฐf An overcharge off refrigerant will cause ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Increased head pressure A drain trap should be installed on a split system when the ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Air handler drain is on the negative side A customer complains that their air conditioning system is running constantly but not cooling enough. The suction line is very cold and the compressor is sweating. The most likely cause is

Which is not a symptom of a hermetic system that is low on refrigerant? ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : High head pressure Frost on the suction line indicates ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : That the temperature is below the dew point and below 32ยฐf An increase in head pressure causes _________ refrigerant to flow through a capillary tube ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : More With an automatic expansion valve, an increase in evaporator load will cause the ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Automatic expansion valve to close When a TEV or capillary tube is used as a metering device, a low refrigerant charge will cause ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Low head pressure What is the maximum operating pressure setting for an acetylene torch? ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : 15 psig When connecting copper to steel, the recommended brazing filler alloy is a ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : 45 percent silver alloy

Solid contaminants, such as sludge and carbon, from a severe hermetic compressor motor burn out are best ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : By flushing the system and then installing filter/ driers in both the liquid and suction lines If the cut-off plate is removed from a blower assembly, how would this affect blower performance? ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : It would reduce air flow 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 ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : An 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 and properly recharged. When the system is started, the compressor is noisy and running hot. The most probable cause of noise is ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Low oil in the system An air conditioning system that is oversized can cause ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Inefficient dehumidification of the conditioned space

๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : High suction pressure and high discharge pressure A dirty evaporator in a air conditioning system will cause these symptoms ๐Ÿ—ธ๐Ÿ—ธ๐Ÿ—ธ : Low suction pressure and low discharge pressure