Test your basic knowledge |

NATE Air Conditioning Troubleshooting

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. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
Increases starting torque
Short cycling and insufficient dehumidification
An overcharged system
The discharge pressure increases and the amperage increases

2. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...
Technician B
A start capacitor and a solid-state relay
20 to 30
A blown fuse

3. The best description of a relay would be...
The sight glass is full of liquid+the sight glass is full of gas
It keeps a constant superheat in the evaporator
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Contains a solenoid coil and one or more sets of contacts

4. A hard-start kit consists of...
Condenser fans operating during a low ambient condition and a low suction pressure
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
Technician B
A start capacitor and a solid-state relay

5. A customer calls and complains that his air conditioning system is not operating properly. It is noticed that the compressor is not operating. A check on the run capacitor shows that there is 33 uf and the rating on the capacitor is 40 uf. Technician
Technician B
Low discharge pressure - high suction pressure - and low amp draw
20 to 30
The sight glass is full of liquid+the sight glass is full of gas

6. What are the operating pressures of an oil pressure safety switch...
Both technicians are incorrect
An undercharged system+insufficient airflow over the evaporator coil
The oil pump pressure and the crankcase pressure
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay

7. A customer calls with an insufficient cooling complaint. Upon arrival to the service call it is found that the outdoor condensing unit is operating - but the indoor blower is not in operation. Technician A says that it is possible that it is a bad fu
Both technicians are incorrect
3 psig
'G' to 'C'
3 psig

8. A hard-start kit for an air conditioning system...
110-120
A start capacitor and a solid-state relay
Increases starting torque
It would cause the low-side pressure to decrease

9. What are possible problems that can cause the discharge-line temperature on an air conditioning system to be cool to the touch...
A restricted metering device
It would cause the low-side pressure to decrease
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

10. What are two common symptoms of a rooftop air conditioning system that operates with a reverse-acting high-pressure control stuck in the closed position...
110-120
Run with high head and high suction pressure
The discharge pressure increases and the amperage increases
Condenser fans operating during a low ambient condition and a low suction pressure

11. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...
An open internal overload protector
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
Run with high head and high suction pressure
Current in the compressor circuit

12. What is the purpose of a CPR valve...
A start capacitor and a solid-state relay
It is used to control refrigerant pressure in the compressor crankcase
Low discharge pressure - high suction pressure - and low amp draw
Low voltage and a faulty start relay

13. Which of the following will cause excessive discharge pressures on an air conditioning system...
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
'G' to 'C'
Always have some liquid present in the bulb and diaphragm
Technician A is correct

14. A restricted air filter in an air conditioning system can be identified by...
Broken rings+broken valves+seized bearings
Low superheat
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Contains a solenoid coil and one or more sets of contacts

15. What are two common symptoms of a rooftop air conditioning system that operates with a reverse-acting high-pressure control stuck in the closed position...
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
Condenser fans operating during a low ambient condition and a low suction pressure
An open internal overload protector
An overcharged system

16. What controls are used on air conditioning or refrigeration systems that incorporate an automatic pump-down system...
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
20 to 30
A dirty condenser - recirculation of condenser air - and a defective condenser fan
3 psig

17. What three things can prevent an air conditioning system from releasing heat at the proper rate...
A low refrigerant charge
An increase in low-side pressure
A dirty condenser - recirculation of condenser air - and a defective condenser fan
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay

18. 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 B
Technician B
Technician A is correct
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

19. Which of the following is a possible cause for a compressor to overheat...
A low refrigerant charge
Clean the condenser coil
A blown fuse
Technician B

20. What is a common discharge temperature of an air-cooled air conditioning system that is used on a 90
It is used to control refrigerant pressure in the compressor crankcase
Technician B
110-120
Low voltage and a faulty start relay

21. A commercial customer calls on a 90
The system has been overcharged+The system has air trapped in the condenser
A start capacitor and a solid-state relay
Technician B
Broken rings+broken valves+seized bearings

22. The internal overload of an air conditioning compressor senses winding temperature and...
('Y' and 'C') and ('G' and 'C')
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
A plugged filter drier
Current in the compressor circuit

23. What are the symptoms of an air conditioning system that has a low charge...
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
The low-side pressure will decrease and the evaporator coil will be partially frosted
An overcharged system
Low discharge pressure - high suction pressure - and low amp draw

24. The technician observes a pressure drop of 25 degrees across an air conditioning evaporator coil at start-up. This drop would indicate...
50-65
Lack of airflow
Broken rings+broken valves+seized bearings
It would cause the low-side pressure to decrease

25. A commercial customer calls complaining that her rooftop air conditioning system is not operating. The technician arrives on the job and sets the thermostat to cooling - then notices that the indoor fan is not operating. The technician then sets the
'G' to 'C'
The discharge pressure increases and the amperage increases
Technician B
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

26. Which of the following can cause excessive subcooling...
Always have some liquid present in the bulb and diaphragm
A bad thermostat
An overcharged system
Bad compressor valve

27. When using a vapor-charged TXV bulb - it is necessary to have...
The sensing bulb at a lower temperature than the valve body
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

28. If a rooftop air conditioning system does not have any means of low ambient protection - what will be two symptoms of the system when operating under a low ambient condition...
High superheat and low discharge pressure
The sight glass is full of liquid+the sight glass is full of gas
A bad thermostat
An acid-core suction line drier

29. 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
A bad thermostat
Both technicians are correct
An uninsulated suction line and a restricted metering device
Lack of airflow

30. What is the purpose of a CPR valve...
Both technicians are correct
Both technicians are correct
It is used to control refrigerant pressure in the compressor crankcase
Current in the compressor circuit

31. What are the operating pressures of an oil pressure safety switch...
An acid-core suction line drier
The oil pump pressure and the crankcase pressure
Contains a solenoid coil and one or more sets of contacts
Condenser fans operating during a low ambient condition and a low suction pressure

32. A liquid-charged TXV bulb will...
High suction pressure and low superheat
Always have some liquid present in the bulb and diaphragm
Run with high head and high suction pressure
Lack of airflow

33. 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
A defective circuit breaker
Whenever necessary
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
Technician B

34. A rooftop package system keeps tripping out on the high-pressure switch. What are three possible causes for this problem...
Dirty condenser - bent condenser fins - and air recirculating over the condenser
A start relay
An uninsulated suction line and a restricted metering device
Condenser fans operating during a low ambient condition and a low suction pressure

35. What is the common cause of a compressor burnout...
An undercharged system+insufficient airflow over the evaporator coil
Always have some liquid present in the bulb and diaphragm
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Technician A is correct

36. When an air conditioning system has an undercharge - what happens to the superheat and the subcooling of the system...
A dirty condenser - recirculation of condenser air - and a defective condenser fan
A plugged filter drier
A bad thermostat
The superheat increases and the subcooling decreases

37. Which of the following could be the cause for a system's discharge and suction pressure being low...
A plugged filter drier
The superheat will increase and the low-side pressure will decrease
A restricted metering device
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged

38. A hard-start kit consists of...
High superheat and low discharge pressure
20 to 30
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
A start capacitor and a solid-state relay

39. If a TXV sensing bulb had lost its charge - what effect would this have on the air conditioning system...
Condenser fans operating during a low ambient condition and a low suction pressure
A vacuum test+oil traces around fittings+soap bubble solution
It would cause the low-side pressure to decrease
A start relay

40. Insufficient airflow can be caused by...
Always have some liquid present in the bulb and diaphragm
An increase of air leakage from ductwork
The sight glass is full of liquid+the sight glass is full of gas
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device

41. The internal overload of an air conditioning compressor senses winding temperature and...
An overcharged system
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
An increase in suction pressure and an increase in discharge pressure
Current in the compressor circuit

42. 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
An undercharge and low ambient conditions
'G' to 'C'
The external equalizer could be plugged
A start capacitor and a solid-state relay

43. What is a common discharge temperature of an air-cooled air conditioning system that is used on a 90
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
110-120
Lack of airflow
The sensing bulb at a lower temperature than the valve body

44. Technician A says ' When charging a system using the superheat method - adding refrigerant to the system will increase the superheat.' Technician B says 'When charging a system using the superheat method - adding refrigerant will decrease the superhe
Partially frosted evaporator and high superheat
The low-side pressure will decrease and the evaporator coil will be partially frosted
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Technician B

45. When troubleshooting a split-system air conditioner - it is found that the compressor motor is humming but not starting. Technician A says that it could be an open internal overload protector. Technician B says that it could be a blown fuse. Which te
The superheat increases and the subcooling decreases
The oil pump pressure and the crankcase pressure
Both technicians are incorrect
The sight glass is full of liquid+the sight glass is full of gas

46. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
A restricted metering device
20 to 30
A blown fuse

47. What component is most often the cause of a start capacitor failure...
Flooding the condenser - cycling condenser fans - and dampering condenser air
110-120
An undercharge and low ambient conditions
A start relay

48. What is a possible cause of a sweat or frost pattern downstream from a sight glass and filter dryer...
The sight glass is full of liquid+the sight glass is full of gas
The discharge pressure increases and the amperage increases
A plugged filter drier
Whenever necessary

49. When using a vapor-charged TXV bulb - it is necessary to have...
110-120
Technician B
The sensing bulb at a lower temperature than the valve body
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor

50. 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
Bad compressor valve
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
Technician A is correct
Both technicians are correct

Test your basic knowledge |

NATE Air Conditioning Troubleshooting

Communication skills, Self help skills, Self improvement skills, Productivity skills, Writing skills, Business skills, Thinking skills & More...

502 Pages | Only $12 | PDF / EPub, Kindle Ready

Top Scores

Link to This Test

Related Subjects