ASE A7 Heating Air Conditioning Exam QUESTIONS WITH COMPLETE 100% VERIFIED SOLUTIONS 2024/, Exams of Refrigeration and Air Conditioning

Download ASE A7 Heating Air Conditioning Exam QUESTIONS WITH COMPLETE 100% VERIFIED SOLUTIONS 2024/ and more Exams Refrigeration and Air Conditioning in PDF only on Docsity! ASE A7 Heating Air Conditioning Exam QUESTIONS WITH COMPLETE 100% VERIFIED SOLUTIONS 2024/2025 A CCOT system has a high high side. Technician A says to suspect the thermostatic expansion valve. Technician B says this system contains an orifice tube. Who is correct? TECH B is correct. A clogged orifice tube will result in high high side pressure. It can become clogged with contaminants, debris from a damaged compressor, or a broken desiccant bag releasing desiccant into the refrigerant. A vehicle's air conditioning performance is reduced at low speeds and stop lights, but cools at highway speeds. Which of these is MOST likely the cause of this condition? A. A low refrigerant charge. B. A missing fan shroud. C. A normal condition. D. A faulty compressor clutch relay. Answer B is correct. A properly fitting and fastened fan shroud is vital for good A/C and engine performance. Many of these shrouds and dams create a low pressure area behind the radiator and condenser. Loose or missing shrouds will be especially noticeable as the vehicle slows and ram air is reduced. Two technicians are discussing an inoperative electric blend door in an automatic air conditioning system. Technician A says to inspect the blend door's wiring and connections for an open circuit. Technician B says to troubleshoot this circuit with a test light. Who is correct? TECH A is correct. An open in the circuit would prevent the blend door's motor operation. A squeal is heard only when the compressor clutch first engages. Technician A says this is caused by a loose serpentine belt. Technician B says this is caused by a worn clutch pulley bearing. Who is correct? TECH A is correct. A loose serpentine belt will cause a squeal when the clutch first engages. A frozen spot is noticed in the center of the condenser. Technician A says a frozen spot on a component or connection indicates a restriction in the system. Technician B says this is caused by a clogged orifice tube. Who is correct? TECH A is correct. A restriction in a line or component acts like a metering device and changes the system's pressure. The change in pressure results in a change in temperature. A technician is diagnosing a vehicle's air conditioning system. The vehicle has good engine performance, but the air conditioner is blowing warm air only. A yellow substance is noticed around the evaporator case drip tube. Technician A says this is coolant leaking from the heater core. Technician B says this is fluorescent dye leaking from the evaporator core. Which technician is MOST likely correct? TECH B is correct. Dye is injected into a system with hard to find leaks. Note that a R-12 system uses one type of dye and a R-134a system uses another. The dye used with R-134a shows up fluorescent yellow. This is brought to light with a special light and glasses. R 134a Refrigerant: A. Changes from a vapor to a liquid as it absorbs heat. B. Containers are sky blue colored. C. Has a very high boiling point. D. Is a CFC that contains chlorine. Answer B is correct. An R134a refrigerant system has less refrigerant capacity than a similar R12 system. They also have different pressure characteristics. R134a is contained in a sky blue container, R-12 is contained in a white container. Two technicians are discussing electric cooling fans and air conditioning performance. Technician A says electric fans regulate refrigerant temperatures more precisely than belt driven fans do. Technician B says electric cooling fans are controlled by control modules that use temperature and pressure actuated sensors and switches. Who is correct? BOTH TECH A AND TECH B. Electric fans offer more precise control than the conventional belt driven fans do. They're important for engine cooling, air conditioning and heater performance. These fans are controlled by a control module that uses pressure and temperature actuated sensors and switches. An air conditioning system with a variable displacement compressor has poor performance in high demand situations. All of these could be the cause EXCEPT: A. A low refrigerant charge. B. A faulty control valve. C. A faulty low pressure switch. D. A weak compressor. Answer C is correct. A variable displacement compressor uses a control valve to alter system pressures. A cycling clutch orifice tube system has a pressure cycling switch on the low side of the system, often located on the accumulator. Technician A says the clutch relay protects the control head from the clutch circuit's high current. Technician B says open clutch relay windings result in compressor clutch engagement at all times. Who is correct? set value, or the sensor or it's circuit is faulty, the automatic temperature control will not engage the compressor clutch. During an initial inspection, the technician notices that one line on the receiver drier is cooler than the other. This is caused by: A. Nothing it's a normal condition. B. A low refrigerant charge. C. Too much oil in the system. D. A restriction in the receiver drier. Answer D is correct. A restriction in the receiver drier will result in a change in line temperatures. This is because one of the properties of refrigerant is that it changes temperature along with pressure. The restriction has altered pressure in the drier and lowered the temperature of the outlet line. Two technicians are discussing refrigerant storage. Technician A says HFC-134a is contained in a sky blue container. Technician B says CFC-12 is contained in a white container. Who is correct? Both technicians are correct. (HFC-134a) R-134a is stored in a sky blue container with a sky blue label, and (CFC-12) R-12 is stored in a white container with a white label. Each refrigerant has its own color assignment. R-12's assignment is white and R-134a is sky blue "light blue". During a performance test on a CCOT system the manifold gauge indicates that the high side pressure is low and the low side pressure is high. This is caused by a: A. Stuck open expansion valve. B. Frozen expansion valve. C. Restricted condenser. D. Faulty compressor. Answer D is correct. A high low side and a low high side indicates a faulty A/C compressor. An air conditioning system blows only warm air when the heater is on high output. Technician A says this could be a faulty heater control valve. Technician B says this could be caused by the cooling system's thermostat. Who is correct? Both technicians are correct. A restricted heater control valve will leave a vehicle with low heater performance. A stuck open thermostat has a negative effect on the heater's performance. Technician A says a fixed orifice tube varies the flow of refrigerant in relation to temperature. Technician B says a fixed orifice tube is located between the condenser and the evaporator. Who is correct? TECH B is correct. The fixed orifice tube is located between the condenser and evaporator core. Technician A says the expansion valve is located on the inlet port of the evaporator. Technician B says the expansion valve's temperature sensing bulb is located near the outlet port of the evaporator. Who is correct? Both technicians are correct.An expansion valve is at the inlet port of the evaporator and the sensing bulb is placed on the outlet port. During a visual inspection an oily spot is found on a hose leading from the compressor. Technician A says there may be a refrigerant leak in the system. Technician B says today's R134a systems use mineral oil instead of the older R12 compatible PAG oil. Who is correct? TECH A is correct. Finding an oily spot on an A/C hose is a quick and easy way to spot a refrigerant leak. Closer inspection and testing will be necessary. An air conditioning system contains a thermostatic expansion valve. The suction line leading to the compressor is cool to the touch. This indicates: A. A stuck open expansion valve. B. A low refrigerant charge. C. A stuck closed expansion valve. D. A normal condition. Answer D is correct. This is a normal condition. All of these are true about an accumulator EXCEPT: A. It is located on the low side of the system. B. It prevents excess liquid from entering the compressor. C. It contains a desiccant capable of absorbing moisture from the refrigerant. D. This system contains a thermostatic expansion valve to meter the refrigerant. Answer D is correct. An accumulator is used on a CCOT or Cycling Clutch Orifice Tube type system. A vehicle has poor air conditioning performance. The customer has added R134a refrigerant to the system. Technician A says to use a refrigerant identifier. Technician B says refrigerant mixtures are not recommended, but will not affect system pressures. Who is correct? Answer A is correct. Use a refrigerant identifier to identify R12, R134a, R22, hydrocarbons and air. An air conditioner with an expansion valve performs poorly only during the hottest times of the day. Technician A says the receiver drier may be saturated. Technician B says there may be moisture in the refrigerant. Who is correct? Both technicians are correct.The receiver drier contains a desiccant that must be changed after it's been exposed to moisture. If saturated with moisture, the excessive moisture in the drier will flow to the expansion valve and freeze, reducing system performance. Poor system performance is most noticeable during the hottest times of the day. Two technicians are discussing a CCOT air conditioning system. Technician A says the system's pressure cycling clutch switch contains a bulb placed on the inlet port of the evaporator core. Technician B says a pressure cycling switch is located on the low side of the system. Who is correct? TECH B is correct. A typical pressure cycling switch is located on the accumulator or the low side of a system. All these statements are true about a throttle position sensor EXCEPT: A. It indicates throttle position to the engine control module. B. The control module disengages the A/C clutch at wide open throttle. C. The ECM disengages the A/C clutch at idle. D. The throttle position sensor signal is used to indicate throttle angle. Answer C is correct. This is an except question. All the other choices are true except this one. The compressor's clutch is not disengaged at idle, it's disengaged at WOT providing additional power when needed. Technician A says refrigerant flows from the top of the condenser to the bottom. Technician B says a restriction in a condenser can cause damage to the compressor. Who is correct? Both technicians are correct. Technician A says evacuating an air conditioning system will remove air, debris, and moisture. Technician B says to evacuate the system any time it's been exposed to the atmosphere. Who is correct? TECH B is correct. Always evacuate the system if it's been exposed to the atmosphere.