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. What are two common symptoms of refrigerant leaks in 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
Whenever necessary
Partially frosted evaporator and high superheat
A start capacitor and a solid-state relay

2. When using a vapor-charged TXV bulb - it is necessary to have...
'G' to 'C'
Technician B
The sensing bulb at a lower temperature than the valve body
Technician B

3. The temperature range of the suction line from an air conditioning system should be...
50-65
An increase of air leakage from ductwork
An uninsulated suction line and a restricted metering device
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay

4. 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
20 to 30
Current in the compressor circuit
A defective circuit breaker

5. What is the common cause of a compressor burnout...
Both technicians are incorrect
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
A defective circuit breaker
Low voltage and a faulty start relay

6. What are the symptoms of an air conditioning system that has a bad compressor discharge valve...
Low discharge pressure - high suction pressure - and low amp draw
Technician A
Evaporator and compressor
An overcharged system

7. What is the purpose of an EPR valve...
An uninsulated suction line and a restricted metering device
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
3 psig

8. Which of the following can cause low superheat in a TXV system...
('Y' and 'C') and ('G' and 'C')
An uninsulated TXV sensing bulb
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser

9. What problem or problems can cause low discharge and suction pressure...
An increase in low-side pressure
An increase in low-side pressure
An undercharged system+insufficient airflow over the evaporator coil
Both technicians are correct

10. Which of the following could be the cause for a system's discharge and suction pressure being low...
3 psig
A restricted metering device
Technician B
Technician A

11. What are two problems that can cause an air conditioning system to have an excessively high superheat...
An undercharged system+insufficient airflow over the evaporator coil
An uninsulated suction line and a restricted metering device
A plugged filter drier
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

12. What three things can prevent an air conditioning system from releasing heat at the proper rate...
Technician B
Low superheat
A dirty condenser - recirculation of condenser air - and a defective condenser fan
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system

13. What is a possible cause of a sweat or frost pattern downstream from a sight glass and filter dryer...
A start capacitor and a solid-state relay
A plugged filter drier
An acid-core suction line drier
Low discharge pressure - high suction pressure - and low amp draw

14. A commercial customer calls on a 90
An uninsulated suction line and a restricted metering device
The system has been overcharged+The system has air trapped in the condenser
Evaporator and compressor
Increases starting torque

15. What problem can cause an increase of discharge pressure and an increase of suction pressure...
A low refrigerant charge
An overcharged system
3 psig
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system

16. Which of the following can cause excessive subcooling...
An overcharged system
An increase of air leakage from ductwork
A bad thermostat
An acid-core suction line drier

17. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...
Technician B
The low-side pressure will decrease and the evaporator coil will be partially frosted
Run with high head and high suction pressure
A dirty condenser - recirculation of condenser air - and a defective condenser fan

18. 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
It is used to control refrigerant pressure in the compressor crankcase
An undercharged system+insufficient airflow over the evaporator coil
Technician B
The external equalizer could be plugged

19. A liquid-charged TXV bulb will...
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
It is used to control refrigerant pressure in the compressor crankcase
Always have some liquid present in the bulb and diaphragm

20. A system that uses a thermal electric expansion valve...
Technician B
3 psig
An increase in low-side pressure
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system

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...
Technician B
Both technicians are incorrect
Technician A is correct
An acid-core suction line drier

22. Insufficient airflow can be caused by...
An increase in low-side pressure
20 to 30
It keeps a constant superheat in the evaporator
An increase of air leakage from ductwork

23. A customer calls with an insufficient cooling complaint on a 90
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Technician B
('Y' and 'C') and ('G' and 'C')

24. If a TXV sensing bulb had lost its charge - what effect would this have on the air conditioning system...
Technician B
It would cause the low-side pressure to decrease
It is used to control refrigerant pressure in the compressor crankcase
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

25. What is the purpose of a CPR valve...
Partially frosted evaporator and high superheat
It is used to control refrigerant pressure in the compressor crankcase
A dirty condenser - recirculation of condenser air - and a defective condenser fan
Low superheat

26. What three things can prevent an air conditioning system from absorbing heat at the proper rate...
The external equalizer could be plugged
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
Bad compressor valve
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

27. The internal overload of an air conditioning compressor senses winding temperature and...
Technician B
It keeps a constant superheat in the evaporator
Current in the compressor circuit
Broken rings+broken valves+seized bearings

28. A restricted air filter in an air conditioning system can be identified by...
Low superheat
An uninsulated TXV sensing bulb
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
An uninsulated suction line and a restricted metering device

29. The temperature range of the suction line from an air conditioning system should be...
('Y' and 'C') and ('G' and 'C')
Technician A is correct
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
50-65

30. What is the purpose of a CPR valve...
110-120
It is used to control refrigerant pressure in the compressor crankcase
The superheat increases and the subcooling decreases
An overcharged system

31. On an are-22 air conditioning system - the suction-line filter drier should be changed when the pressure drop dictates...
An acid-core suction line drier
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
3 psig
The low-side pressure will decrease and the evaporator coil will be partially frosted

32. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
50-65
A vacuum test+oil traces around fittings+soap bubble solution
A missing air filter+improper rotation of the indoor blower+blower too small
('Y' and 'C') and ('G' and 'C')

33. What are the symptoms of a TXV air conditioning system if it has lost its charge...
The superheat will increase and the low-side pressure will decrease
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
Whenever necessary
A low refrigerant charge

34. When an air conditioning system has an undercharge - what happens to the superheat and the subcooling of the system...
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
It keeps a constant superheat in the evaporator
The superheat increases and the subcooling decreases
Both technicians are incorrect

35. What component is most often the cause of a start capacitor failure...
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
A start relay
Technician A is correct
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged

36. A commercial customer calls on a 90
The system has been overcharged+The system has air trapped in the condenser
Evaporator and compressor
110-120
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system

37. When a high-efficiency split air conditioning system has a plugged metering device - what symptoms might occur...
Clean the condenser coil
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Technician B

38. What are the symptoms of an air conditioning system that has a low charge...
Clean the condenser coil
Low superheat
It keeps a constant superheat in the evaporator
The low-side pressure will decrease and the evaporator coil will be partially frosted

39. What is the common cause of a compressor burnout...
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
A plugged filter drier

40. 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...
Always have some liquid present in the bulb and diaphragm
Whenever necessary
The internal overload is opened
Dirty condenser - bent condenser fins - and air recirculating over the condenser

41. What is a possible cause of a sweat or frost pattern downstream from a sight glass and filter dryer...
A plugged filter drier
'G' to 'C'
'G' to 'C'
Technician A

42. A customer who owns a split air conditioning system complains that his system has been running but his house doesn't seem to be cooling properly. When the service technician arrives on the job - he or she finds that the indoor blower is operating and
An undercharge and low ambient conditions
Flooding the condenser - cycling condenser fans - and dampering condenser air
'G' to 'C'
Clean the condenser coil

43. If 24 volts are present to the contactor coil on an air conditioning system and the condenser fan or compressor is inoperative - which of the following could be at fault...
Contains a solenoid coil and one or more sets of contacts
Increases starting torque
A blown fuse
Whenever necessary

44. Superheat is found in an air conditioning system in the...
Evaporator and compressor
Increases starting torque
The external equalizer could be plugged
Bad compressor valve

45. 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...
It keeps a constant superheat in the evaporator
The internal overload is opened
110-120
High superheat and low discharge pressure

46. Which of the following is a possible cause for a compressor to overheat...
A low refrigerant charge
It would cause the low-side pressure to decrease
Contains a solenoid coil and one or more sets of contacts
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device

47. A customer calls and says that her air conditioning system is not cooling properly. Upon arrival - a technician notices that the suction line and compressor have frost buildup. Technician A says that the problem is probably a low charge. Technician B
50-65
Technician B
Rise more than normal
Whenever necessary

48. 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...
Flooding the condenser - cycling condenser fans - and dampering condenser air
A vacuum test+oil traces around fittings+soap bubble solution
An undercharge and low ambient conditions
High superheat and low discharge pressure

49. A system that is being serviced has been evacuated down to 500 microns. When the gauges are closed and the vacuum pump is turned off - the pressure starts to increase and stops at 1000 microns. Technician A says that the system has a leak and needs t
An overcharged system
Technician B
Condenser fans operating during a low ambient condition and a low suction pressure
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor

50. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
An increase of air leakage from ductwork
Technician B
The discharge pressure increases and the amperage increases
Both technicians are incorrect