Who is correct? By visiting this website, certain cookies have already been set, which you may delete and block. Technician A says that the suction valve is opened to allow refrigerant vapor to enter due to a differential in pressure above and below the valve. Who is correct? When the compressor is engaged, the high-side pressure instantly goes over 375 psig. Technician B says a defective pressure valve may cause coolant boil over and loss. Pressure switches are being discussed: Technician A says that a test lamp should never be used to test the operation of a pressure switch. Appliances with motor usually require more wattage to kick off. Technician B says this positive pressure is necessary to provide a proper balance of air pressure within the air delivery system. Who is correct? Dye leak detectors are being discussed. Locked rotor amperage is also called inrush current . Technician B says that a check valve permits vacuum flow in either direction. The temperature fluctuates between hot and cold on a vehicle equipped with an automatic temperature -control system. Which of the following could be the possible cause? Technician B says that there are provisions for ¬connecting an external scan tool on some systems. Technician B says that a restricted expansion valve inlet screen could be the cause. A technician finds an air-conditioning clutch will not engage. EDIT: Added nice closeup of EF1 to EF5 by tobesscooby 4/6/2013. Technician B says overcharging the system will reduce its cooling efficiency. What could be the problem? Who is correct? Technician A says the refrigerant must be weighed (or metered) to obtain a proper charge. Pump low-pressure vapor to a high-pressure vapor. A rattling noise is heard when the engine is running and the air conditioning is off. Technician A says that when working on a refrigerant system you should work in a well-ventilated area. Technician B says that a cracked radiator to recovery tank hose could be the cause. Technician B says the containment system (tanks and lines) must withstand the changing pressures created as the liquid changes states. Technician A says that a red label is required to identify R-134a in an automotive air-conditioning system. On a vehicle equipped with front and rear A/C dual evaporator system, the front evaporator cools properly, but the rear evaporator is warm. This will not maintain an active evaporator, and system capacity will suffer.Â. An inoperative vacuum motor could be caused by all of the following, except. Who is correct? What is your strategy for vaccinating your employees? What is the most likely cause of this condition? I want to hear from you. Technician A says there is a direct relationship between the pressure and temperature of a refrigerant. High resistance in the compressor clutch electrical circuit. Who is correct? Technician B says the use of test lights is not recommended for under dash service. Refer to the appropriate diagnostic fault chart. Which of the following is the most likely cause? Then, all it takes to learn required wattage is to apply this equation: Watts (W or kW) = Volts (V) x Amps (A) number of batteries as well as solar panels) if the need is an earth closet with an electrical rotor (25 W-AC with 230 VAC that goes ca 1.5 minutes after each use. i have a ford tractor with ac. Where in the system is the receiver dryer located? Technician A says the engine should be operated at speeds over 3,000 rpm during the test. Plasma Cutter 45 Amps Portable AC 220V IGBT Inverter 1/2" Clean Cut CUT-45 Air Plasma Cutting Machine High Frequency Duty Cycle for Aluminum Stainless Mild Steel Copper Iron Chrome 285.00 $ 285 . Who is correct? The Clean Air Act is being discussed. Who is correct? The retrofit label's background color for R-134a refrigerant is: Refrigerant contamination is being discussed. technician A says that the A/C system may be charge through the LOW side when the system is operating. Technician B says it gave the EPA authority to control refrigerants in order to protect the environment. Who is correct? Tell me how we can improve. Answer: The 24 volts comes from a low voltage transformer.Please see the pictures of the two transformers below. Both agree that the residue must be disposed of in a proper manner. Again, this compressor had more than 20° of superheat coming to it, meaning liquid refrigerant cannot be present. Technician A says if the analyzer displays "R-134a," then the refrigerant is 98 percent pure. You must have JavaScript enabled to enjoy a limited number of articles over the next 30 days. Join The NEWS on Facebook, Twitter, and LinkedIn today! Technician B says refrigerant system O-rings can be coated with a gasket sealant. GFCI Receptacle Tester for North American AC Electrical Outlet Receptacles Klein Tools Receptacle Testers are designed to detect the most common wiring problems in standard and GFCI receptacles. Who is correct? Technician B says debris in the fresh air intake can contaminate the refrigerant. Technician A says if the compressor clutch coil voltage drop is equal to source voltage (battery) then the clutch coil is defective. However, HYUNDAI reserves the right to make changes at any time so that our policy of continual product improvement may be carried out. Reciprocating compressors are being discussed. During normal air-conditioning system operation, the position of the system mode doors: The following statements about a typical system set to MAX cooling are true, except: Technician A says mode doors may be vacuum operated. To get the precise numbers, you will need to find the voltage, amperage, and horsepower information on the info-plate of your compressor. Which of the following is the most likely cause? You can buy this product here. Technician B says that its function is to increase the temperature and pressure of refrigerant vapor. Heating, ventilation, and air conditioning (HVAC) is the technology of indoor and vehicular environmental comfort. Technician B says that it is almost impossible to remove a seal seat that has been installed backward. Technician A says that a thermostat is used for temperature control in some systems. Technician A says that the expansion valve stuck in the open position could be the cause. The EasyStart can reduce start current by 65-75% compared to a compressor’s LRA (locked-rotor amperage). Technician A says an in-car temperature sensor may be tested by measuring its resistance at 70˚F and 80˚F. Technician B says a fan should be used to force air through the condenser and radiator. The angle of the swash plate in a variable displacement compressor is controlled by: Suction pressure differential in the crankcase. Who is correct? What operation should the technician perform first? Ellsworth, KS 67439. Technician B says that the check valve prevents ¬vacuum loss when the engine is stopped. By closing this message or continuing to use our site, you agree to the use of cookies. Technician B says that a faulty compressor clutch bearing could be the cause. Most manufacturers of larger evaporators supply a Schrader fitting at the evaporator outlet close to the remote bulb of the TXV for measuring pressure. Before installation: Technician A says that refrigerant system O-rings should be coated with new refrigerant oil. Technician A says the Montreal Protocol is one of the results of the Clean Air Act. The following statements regarding a visual inspection for intermittent faults are all true, except: Inspect for catastrophic component failure. Who is correct? Technician B says that the discharge valve is opened to allow refrigerant vapor to leave due to a differential in pressure above and below the valve. All of the following statements are true, except: A refrigerant identifier will identify R-134a at any purity. This reading could be caused by: A leaking evaporator is being replaced. Who is correct? Performance testing on air conditioning is being discussed. Technician A says that the seal cavity may be flushed with clean refrigeration oil. Evaporator superheat is measured as the difference between the actual temperature of the refrigerant vapor at the evaporator outlet and the saturation temperature of the refrigerant at that same point as taken from the pressure/temperature chart (see Equation 1). Who is correct? These devices offer a solution that allows an air conditioner to operate on a generator, inverter, or limited utility power when it would otherwise not have functioned. Technician A says a sun load sensor may be tested by placing a dark piece of cloth over sensor while observing data values on a scan tool. Who is correct? Technician B says that a serpentine belt system is often used to drive a compressor clutch. Technician A says that the evacuation process will remove dirt and debris from the refrigerant system. By closing this message or continuing to use our site, you agree to the use of cookies. In the picture, this is a Dual Run Capacitor and reads 55+5 MFD (uf) 440 VAC. Who is correct? The following may be used to maintain in-vehicle ¬temperature, except: When the air-conditioning switch is turned to the OFF position, the compressor clutch stays engaged. Picture & amperage & description of every single fuse & relay in the BMW E39 EDIT: Added excellent fuse descriptions from Steve530 from post #4 on 3/3/2012. Technician B says that the clutch will slip if the belt is close. The recommended minimum efficiency of a vacuum pump at sea level atmospheric pressure is being discussed: After retrofitting a vehicles air conditioning system from R-12 to R-134a a retrofit label should be affixed under the hood containing the following information, except: Which of the following desiccants should be used with HFC-134a refrigerant? A frosted suction line and suction gas porting section of an air-cooled compressor’s head. Who is correct? Technician B says a quick accurate test is to see if the clutch is the source is to switch on the air conditioning to see if the noise stops. An undercharged system will show which of the following gauge readings? Who is correct? Who is correct? An odor from the evaporator may be caused by all of the following, except: The airflow path in the case/duct system illustrated in Figure 10-52 is being discussed: The rear evaporator duct is cooling properly on a vehicle with a rear heating and cooling system, but the front evaporator duct temperature is too warm. Technician B says that a liquid antimicrobial ¬deodorizer and disinfectant is used to eliminate odors in duct systems. Use the dropdowns below to help you estimate what size air conditioner is best for your space. Some suggested evaporator superheat amounts for various applications. What does the air conditioning compressor do to the system refrigerant? What could happen if the evaporator pressure becomes too low? The least likely cause of an inoperative vacuum motor is: Technician A says that a slight amount of conditioned air is made available at the defroster duct outlet at all times to prevent windshield fogging. There will always be a time when the evaporator sees a light heat load and the TXV may lose control of its evaporator superheat due to limitations of the valve and to system instability. If the compressor oil has been drained and it shows signs of metallic particles, all of the following should be done, except: A full charge of heavier refrigeration oil should be added after flushing. Technician B says that R-12 O-rings are blue or green. A vehicle returns to the shop for a repeat failure of the compressor system due to compressor clutch slippage and overheating. The Hobart® Champion® Elite 225 welder is now more quiet than previous models, yet still packs up to 225 amps of DC welding output. Who is correct? The following statements regarding the relationships between the cooling system and air-conditioning -system are all true, except: Ambient air first passes through the radiator, then the condenser. An air-conditioning compressor clutch failed due to overheating. Technician A says that a leaking compressor shaft seal could be the cause. Technician A says that POE is compatible with R-134a. During normal comfort control operation with the windows closed, harmful gases are not allowed to enter the vehicle because: Technician A says when a musty odor develops the odor causing mold and mildew must be eradicated. Most original equipment manufacturers use what type of lubricant in their R-134a systems? Who is correct? Evaporation is being discussed. Technician A says that its function is to create a low pressure condition in the system. If there ever is a time where the compressor superheat drops to zero, there now could be liquid refrigerant coming back to the compressor. Technician A says that a DOT 39 cylinder may be used to temporarily store contaminated refrigerant. Technician A says that O-rings designated for R-12 service do not need to be changed for retrofit. Technician B says a special lamp is required to locate a small leak with fluorescent dye. Technician A says that serpentine belts made of EPDM resist cracking and instead exhibit wear to the belt ribs similar to tire wear and that a depth gauge should be used to assess belt wear. Technician A says the pressure in a tank will increase as the liquid cools. Compressor superheat is measured as the difference between the actual suction line temperature of the refrigerant vapor and the saturation temperature of the refrigerant arrived at from a pressure/temperature relationship. An electronic thermostat is out of specification. All of the following air-conditioning system sensors are varying resistive sensors except. Which of the following is the most likely cause? Who is correct? All of the follow are true about engine thermostats EXCEPT: A thermostat should be removed from a system if it is running hot. It looks like your browser needs an update. Who is correct? On the other hand, excessive superheat in the suction gasses and/or long periods of low mass flow rate (for example, an unloaded compressor or variable-capacity compressor at lower capacities) can result in insufficient cooling of the rotor, motor, and stator and open the internal protectors. Technicians usually place an insulated thermistor or thermocouple at the evaporator outlet to get the evaporator outlet temperature. It starts at the 100 percent saturated vapor point in the evaporator and ends at the compressor inlet. Which of the following is the most likely cause? It is important for service technicians to differentiate between evaporator superheat and compressor superheat. Technician B says if "HC" is displayed, then the refrigerant is flammable. Who is correct? The heat added to a vapor causing it to become warmer is called: The temperature of superheated refrigerant is. Who is correct? During a routine fluid level inspection a radiator is found to be low on coolant. This is where total superheat comes into play. By visiting this website, certain cookies have already been set, which you may delete and block. Freezing of this condensation (sweat) may also occur if suction line temperatures are below 32°, and water damage can occur once the ice or frost melts. Electrical testing is being discussed: Technician A says that an analog ohmmeter should not be used to test an electronic circuit. The cooling power of different types of air conditioners is based on BTU’s. Who is correct? This will overload the compressor in many instances and could open thermal overloads. Moisture will freeze on the evaporator surface restricting air flow. A pressure reading also will be needed at this same location. Copyright ©2021. Technician B says that the evacuation process will remove moisture and air from the refrigerant system. This could cause compressor damage from liquid flooding or slugging from too low of a superheat setting. All of the following statements about a typical air-¬conditioning system set to MAX cooling are true, except: The heater coolant flow control valve is open. Technician A says that an evaporator is a heat exchanger. Who is correct? The proper amount of compressor superheat will ensure a cool running compressor and, at the same time, ensure the proper density suction gasses for good capacities. The Champion Elite is an 11,000 watt AC generator and DC stick welder that can weld up to 1/2" steel in a single pass. Technician B says mode doors may be electrically operated. Which of the following is the most likely cause? Running watts (or rated watts) – these mean how much energy the appliance needs to run after the initial startup. This will cause the pressure at the compressor to be lower than the pressure at the evaporator outlet. Which of the following is the most likely cause? Compressor or total superheat assures there is no liquid refrigerant present at the compressor, and the saturated vapor in the evaporator has gained some sensible heat before reaching the compressor. What is the most likely cause of this condition? Technician A says air conditioning is the process of controlling the passenger compartment comfort level. Remember, the TXV controls evaporator superheat. All of the following may need to be performed as part of a retrofit procedure from R-12 to R-134a refrigerant, except, Replace all air conditioning system hoses with ¬barrier hoses. Technician A says that a trouble code may be displayed on some master control heads. This will cause the suction line to sweat from water vapor in the air reaching its dew point on the suction line. Both high- and low-side service ports are located on the A/C compressor. A convenient chart on the tester helps determine wiring condition in outlet, based on LED lights results. This website requires certain cookies to work and uses other cookies to help you have the best experience. Its goal is to provide thermal comfort and acceptable indoor air quality.HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics and heat transfer. Technician B says an infrared temperature sensor may be tested by alternately placing a cold damp towel and a hot damp towel in front of the sensor while observing data values on a scan tool. Who is correct? Technician B says it is safe to work on electric cooling fan motors when the ignition switch is off. In many cases, the compressor, suction line, or a component in the suction line will be below freezing temperatures and will have frost accumulation while still operating normally. Under normal operating conditions all of the following occurs inside the evaporator, EXCEPT: The refrigerant changes from a vapor to a liquid. Thinking that liquid refrigerant must be present because there is frost is a fallacy in most cases, especially when dealing with medium- and low-temperature refrigeration. To give you a better example – a typical 10,000 air conditioner consumes 2,200 starting watts. If a thermostat fails in the open position, all of the following will occur, EXCEPT: An engine coolant temperature switch or sensor is used to directly or indirectly energize the: Technician A says some coolants are ethylene glycol. An inoperative cooling fan may cause high lead (high-side) pressure at what vehicle speeds? All of the following are removed from an air-¬conditioning system during evacuation, except: Technician A says that the new refrigerant installed must be identified on the retrofit label. Technician B says the some refrigerant oil should be added to the system prior to recharging the system. Technician A says that up to 20 percent of fresh air provides a means to maintain a positive in-vehicle pressure when the windows are closed. Compressor or total superheat will be a buffer in case the TXV loses control of superheat at these low loads. Technician B says that a positive in-vehicle ¬pressure is maintained at all times to prevent exhaust gas infiltration. Who is correct? Replacement of hoses during retrofit procedures is being discussed. To access the box, unscrew retaining nuts (2) and remove the cover (1). The shims shown in the illustration are used to. Frost accumulating on the suction line, suction service valve, and end bell of a suction gas-cooled compressor. When retrofitting, the proper R-134a charge of ¬refrigerant is about _______________ of the original R-12 refrigerant charge. Thermal Arc Fabricator 252I W1004403. Technician B says the orifice tube is located in the liquid line between the condenser outlet and evaporator inlet. Technician B says a quick accurate test is to see if the clutch is the source is to switch on the air conditioning to see if the noise stops. Technician B says that at atmospheric pressure a low - pressure switch should be normally closed. Many appliance and refrigerated case manufacturers are working with compressor manufacturers to determine the optimum amount of compressor superheat so as not to overheat compressors. On a vehicle equipped with and automatic temperature control system the blower motor will not function when the vehicle is first started and heat is selected. Which of the following is the most likely cause? Therefore, it is always best to measure the pressure at the same location as you measured the temperature to exclude any system pressure drops. Technician A says latent heat cannot be felt. The lower number is always going to be for the fan motor. Which of the following is the best description of a pressure switch designated NC? The transformer has a primary (high voltage side) and a secondary (low voltage side). To measure and adjust compressor clutch air gap, a _______________ feeler gauge should be used. Then the voltage 440 Volts AC. After stabilizing the air-conditioning system, the engine speed is returned to normal. How is heat transfer by convection accomplished? Technician A says that it is virtually impossible to insert the seal seat backward when using the appropriate tool. Design, CMS, Hosting & Web Development :: ePublishing. Technician B says that the electronic leak detector requires routine calibration and probe tip inspection and maintenance. A manifold and gauge set is attached to an operating air conditioner. Technician A says the amount of refrigerant flowing through an orifice tube is controlled by a remote sensing bulb. How to Calculate How Many BTU’s You Need. Technician A says the new o-rings should be coated with clean refrigerant oil. Who is correct? On a system that uses an accumulator what type of metering device is used? A vehicle's automatic temperature control system does not hold the temperature set on the temperature -control assembly. An R-134a expansion valve system that is properly charged has the following gauge readings, high-side 150 psig and low-side 42 psig and the ambient air temperature is 85°F. Who is correct? Technician A says that a vacuum reserve tank helps maintain a vacuum in the system at all times only when the engine is running. Which of the following could cause very low pressures on the low side of a system equipped with an expansion valve? Technician B says that a condenser is a heat exchanger. Which of the following is the most likely cause? Who is correct? Technician B says that a low-pressure control is used for temperature control in some systems. Who is correct? Technician A says in an H-block valve the temperature sensing sleeve (bulb) is internally located in the outlet port of the valve. Which of the following is the most likely cause? As the refrigerant travels the length of the suction line, there will be an associated pressure drop from friction and/or restrictions caused by long runs of suction piping, oil accumulation, filters, or valves. Who is correct. It is necessary to drain the engine coolant before replacing which component? Once Upon a Pre-Pandemic Time in Hollywood AC Hagan Experience the rich culture of Italy with Stanley Tucci's new show Jaime Hutkin Love is in the air: a … Technician A says this noise may be caused by too narrow gap between the compressor's armature and rotor. A rattling noise is heard when the engine is running and the air conditioning is off. What is the most likely cause of the failure? All of the following conditions could cause poor passenger compartment heating system performance EXCEPT, The metering device changes high-pressure liquid into a. So please give the end answer (i.e. After a vehicle has been driven for 10-15 miles, the heater still continues to blow cool air. Service technicians will often experience frost on a suction line or on the compressor in some refrigeration applications. Technician A says that a check valve prevents vacuum flow in either direction. Husky Ultra-Quiet 30 Gal. Problem: Why I am not getting 24 volts to the contactor?Where does the 24 volts come from? A buffer of compressor superheat will also ensure the refrigerant vapor entering the compressor is not too dense. Density vapors that are too high and enter the compressor will cause the compressor to have a higher than normal amperage draw. Technician B says that the seal cavity may be flushed with clean mineral spirits. Who is correct? The 100 percent saturated vapor point is the point where all the liquid has just turned to vapor and is the saturated evaporator temperature. Who is correct? Total or compressor superheat consists of evaporator superheat plus suction line superheat. During routine equipment inspection a technician notices that the R-134a recovery tank pressure is 115 psig at an ambient tank temperature of 85°F. The compressor changes a low-pressure vapor to. Technician A says a defective radiator cap vacuum valve may cause hoses to collapse. Who is correct? compressor contains a cast iron, V-twin cylinder and oil-lubricated pump features 1-Piece cast iron crankcase, thermally stable cast iron cylinder body, aluminum head and machined cast iron valve plate, automotive style ball bearings and … Page 1 S S p p e e c c i i f f i i c c a a t t i i o o n n s s All information in this Owner's Manual is current at the time of pub- lication. Do not sacrifice (raise) evaporator superheat to get the amount of total superheat needed. Technician A says that a faulty radiator cap could be the cause. A pressure gauge at the same point as the temperature reading will give the technician the saturated vapor temperature. On a refrigerant system there is heavy frost on the expansion valve inlet and low-side pressure is well below normal. Please click here to continue without javascript.. A slipping compressor clutch may be due to all of the following, except: The following are automotive air-conditioning system compressor types, except. Who is correct? To ensure the best experience, please update your browser. All of the following statements about variable displacement compressors are true, except: Variable displacement compressors have a cycling clutch. Technician A says you should always disconnect the power source while working on electric cooling fan motors. It is recommended that all TXV-controlled refrigeration systems have some compressor superheat to ensure the compressor will not see liquid refrigerant (flooding) at low evaporator heat loadings. The Hobart Champion Elite 225 welder/generator is designed to be a jobsite workhorse. Visit our updated, This website requires certain cookies to work and uses other cookies to help you have the best experience. Technician A says that the electronic leak detector probe should be held directly against a suspected leak area during a leak test. Upon initial testing the compressor is receiving both proper power and ground at the compressor clutch electrical connector; in addition the compressor input shaft turns freely by hand. The suction filter, suction line, and end bell of the compressor are all frosted; however, in this system, the evaporator had more than 10° of evaporator superheat, and the compressor had more than 25° of superheat. A customer complains of the passenger compartment temperature always being too hot, cold, or not changing as the temperature range is changed on the control panel. Who is correct? All of the following statements about system evacuation are true, except: If vacuum does not reach 24 to 26 in. Technician B says pure refrigerant temperature-pressure relationships in a contaminated system are not valid.