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Test your basic knowledge |
NATE Air Conditioning Troubleshooting
Start Test
Study First
Subjects
:
engineering
,
nate
Instructions:
Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can
study here
.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.
This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. What are two common problems that can cause a sight glass in an air conditioning to have bubbles...
Technician A
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
An undercharge and low ambient conditions
2. The technician observes that the compressor is not operating. The compressor windings read 5 ohms start to run - run to common is opened - and start to common is opened. The technician concludes that...
Condenser fans operating during a low ambient condition and a low suction pressure
The internal overload is opened
An undercharged system+insufficient airflow over the evaporator coil
Always have some liquid present in the bulb and diaphragm
3. Technician A says that if you connect 208 volts to the primary side of a 240-volt/ 24-volt transformer - the transformer will burn out. Technician B says that if you connect 208 volts to the primary side of a 240-volt/24-volt transformer - the contro
Evaporator and compressor
Technician B
20 to 30
Both technicians are incorrect
4. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
A missing air filter+improper rotation of the indoor blower+blower too small
High superheat and low discharge pressure
An acid-core suction line drier
5. A system that uses a thermal electric expansion valve...
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
An undercharge and low ambient conditions
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
An acid-core suction line drier
6. What are the symptoms of an air conditioning system that has a low charge...
Technician A
The low-side pressure will decrease and the evaporator coil will be partially frosted
Always have some liquid present in the bulb and diaphragm
The internal overload is opened
7. What is the purpose of an EPR valve...
It is used to control refrigerant pressure in the compressor crankcase
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Technician A is correct
Partially frosted evaporator and high superheat
8. What causes the automatic expansion valve to close...
An increase in low-side pressure
An undercharge and low ambient conditions
The superheat will increase and the low-side pressure will decrease
The sensing bulb at a lower temperature than the valve body
9. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
The discharge pressure increases and the amperage increases
Both technicians are correct
The external equalizer could be plugged
Technician B
10. What component is most often the cause of a start capacitor failure...
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
A missing air filter+improper rotation of the indoor blower+blower too small
A start relay
An increase in low-side pressure
11. A hard-start kit for an air conditioning system...
Evaporator and compressor
Current in the compressor circuit
Technician B
Increases starting torque
12. What is the purpose of an EPR valve...
It is used to control refrigerant pressure in the compressor crankcase
Condenser fans operating during a low ambient condition and a low suction pressure
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
A defective circuit breaker
13. Technician A says that to manually pump down an air conditioning system with a two-position service valve - the liquid line must be front-seated and the high- and low-side pressure will decrease to 0 psig when the pump-down is complete. Technician B
Technician A is correct
Rise more than normal
('Y' and 'C') and ('G' and 'C')
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
14. A customer calls and complains that her high-efficiency air conditioning system is operating - but is not cooling properly. Further investigation shows that the system is using a TXV type of metering device. A subcooling check shows that the system a
The external equalizer could be plugged
The sight glass is full of liquid+the sight glass is full of gas
A restricted metering device
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
15. What are three methods for controlling a system's high-side pressure during low ambient conditions...
('Y' and 'C') and ('G' and 'C')
Technician A
Flooding the condenser - cycling condenser fans - and dampering condenser air
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
16. When using a vapor-charged TXV bulb - it is necessary to have...
The sensing bulb at a lower temperature than the valve body
Current in the compressor circuit
Contains a solenoid coil and one or more sets of contacts
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
17. A compressor motor starts and operates for a short period of time and cycles on the external overload protector. What are two possible problems that could cause this...
Low voltage and a faulty start relay
A low refrigerant charge
A vacuum test+oil traces around fittings+soap bubble solution
The sensing bulb at a lower temperature than the valve body
18. Technician A says that if you connect 208 volts to the primary side of a 240-volt/ 24-volt transformer - the transformer will burn out. Technician B says that if you connect 208 volts to the primary side of a 240-volt/24-volt transformer - the contro
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Contains a solenoid coil and one or more sets of contacts
Evaporator and compressor
Technician B
19. If a TXV sensing bulb had lost its charge - what effect would this have on the air conditioning system...
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
20 to 30
It would cause the low-side pressure to decrease
3 psig
20. What problem or problems can cause low discharge and suction pressure...
Low discharge pressure - high suction pressure - and low amp draw
The oil pump pressure and the crankcase pressure
An uninsulated TXV sensing bulb
An undercharged system+insufficient airflow over the evaporator coil
21. After a compressor motor has been severely burnt - What accessory must be added as an aid to rid the air conditioning system of acid...
Both technicians are incorrect
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Flooding the condenser - cycling condenser fans - and dampering condenser air
An acid-core suction line drier
22. What are two common symptoms of an overcharged air conditioning system that uses a capillary-tube-type metering device...
Lack of airflow
Technician B
An increase in suction pressure and an increase in discharge pressure
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
23. Which of the following could be the cause for a system's discharge and suction pressure being low...
Partially frosted evaporator and high superheat
A restricted metering device
Technician B
Technician B
24. The best description of a relay would be...
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
Contains a solenoid coil and one or more sets of contacts
An overcharged system
Increases starting torque
25. Air filters should be replaced...
An acid-core suction line drier
The superheat will increase and the low-side pressure will decrease
Whenever necessary
Both technicians are correct
26. What causes the automatic expansion valve to close...
The internal overload is opened
Technician A is correct
An increase in low-side pressure
The superheat will increase and the low-side pressure will decrease
27. What is a possible cause of a sweat or frost pattern downstream from a sight glass and filter dryer...
Both technicians are incorrect
A plugged filter drier
An uninsulated TXV sensing bulb
The internal overload is opened
28. The technician observes that the compressor is not operating. The compressor windings read 5 ohms start to run - run to common is opened - and start to common is opened. The technician concludes that...
Technician B
An uninsulated suction line and a restricted metering device
The internal overload is opened
A vacuum test+oil traces around fittings+soap bubble solution
29. The temperature range of the suction line from an air conditioning system should be...
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
50-65
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
30. A 220-volt 30-amp motor circuit keeps tripping the breaker after the motor is started. The starting amperage is 60 amps. When measuring the amperage of the circuit - This is drawn for a brief moment. After startup - the amperage drops to 22 amps and
The external equalizer could be plugged
A defective circuit breaker
Flooding the condenser - cycling condenser fans - and dampering condenser air
Technician B
31. An air conditioning system that uses a fan center has an inoperable indoor blower. When the thermostat is set for cooling and dialed below room temperature - a test with the voltmeter shows that there is 24 volts across terminals 'are' and 'G' at the
Both technicians are correct
Bad compressor valve
Technician B
A bad thermostat
32. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...
20 to 30
An increase in suction pressure and an increase in discharge pressure
The oil pump pressure and the crankcase pressure
A dirty condenser - recirculation of condenser air - and a defective condenser fan
33. A technician arrives on the job and the customer complains that there is no cooling on his rooftop unit. Troubleshooting the system - the technician finds that the compressor is faulty. He notices that there is another faulty compressor laying next t
Broken rings+broken valves+seized bearings
50-65
Technician B
A start relay
34. A system that uses a thermal electric expansion valve...
Bad compressor valve
The low-side pressure will decrease and the evaporator coil will be partially frosted
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
An overcharged system
35. What is the purpose of the TXV...
Technician B
Technician B
Rise more than normal
It keeps a constant superheat in the evaporator
36. A hard-start kit for an air conditioning system...
Run with high head and high suction pressure
Increases starting torque
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
37. Which of the following is a possible cause for a compressor to overheat...
An undercharged system+insufficient airflow over the evaporator coil
It keeps a constant superheat in the evaporator
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
A low refrigerant charge
38. Which of the following can cause low superheat in a TXV system...
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
Low voltage and a faulty start relay
An uninsulated TXV sensing bulb
Technician A
39. After a compressor motor has been severely burnt - What accessory must be added as an aid to rid the air conditioning system of acid...
An acid-core suction line drier
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
High suction pressure and low superheat
Low superheat
40. What are the symptoms of an air conditioning system that has a low charge...
'G' to 'C'
An increase in suction pressure and an increase in discharge pressure
It keeps a constant superheat in the evaporator
The low-side pressure will decrease and the evaporator coil will be partially frosted
41. Which of the following will cause excessive discharge pressures on an air conditioning system...
The system has been overcharged+The system has air trapped in the condenser
Always have some liquid present in the bulb and diaphragm
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
The superheat will increase and the low-side pressure will decrease
42. What is the common cause of a compressor burnout...
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
Condenser fans operating during a low ambient condition and a low suction pressure
Technician A is correct
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
43. A rooftop package system keeps tripping out on the high-pressure switch. What are three possible causes for this problem...
An increase in low-side pressure
Broken rings+broken valves+seized bearings
Dirty condenser - bent condenser fins - and air recirculating over the condenser
The superheat will increase and the low-side pressure will decrease
44. What are two problems that can cause an air conditioning system to have an excessively high superheat...
A restricted metering device
('Y' and 'C') and ('G' and 'C')
An open internal overload protector
An uninsulated suction line and a restricted metering device
45. Superheat is found in an air conditioning system in the...
A start capacitor and a solid-state relay
Evaporator and compressor
The low-side pressure will decrease and the evaporator coil will be partially frosted
Broken rings+broken valves+seized bearings
46. A split-system air conditioner that uses a piston-type metering device is to be charged with are-22. Technician A says that the outdoor dry-bulb temperature is needed to determine the proper superheat. Technician B says that the indoor wet-bulb tempe
The discharge pressure increases and the amperage increases
An increase of air leakage from ductwork
Clean the condenser coil
Both technicians are correct
47. Which of the following will cause excessive discharge pressures on an air conditioning system...
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
An undercharged system+insufficient airflow over the evaporator coil
48. What type of problems can be caused by an oversized air conditioning system...
The superheat will increase and the low-side pressure will decrease
The oil pump pressure and the crankcase pressure
Short cycling and insufficient dehumidification
An overcharged system
49. An air conditioning unit has a suction line that is frosted up to the compressor. What faults could cause this to occur...
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Whenever necessary
Technician B
Dirty condenser - bent condenser fins - and air recirculating over the condenser
50. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...
The internal overload is opened
The system has been overcharged+The system has air trapped in the condenser
Technician B
Run with high head and high suction pressure
Sorry!:) No result found.
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