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 the symptoms of an air conditioning system that has a bad compressor discharge valve...
Low voltage and a faulty start relay
Low superheat
Low discharge pressure - high suction pressure - and low amp draw
Short cycling and insufficient dehumidification

2. What are the symptoms of an air conditioning system that has a bad compressor discharge valve...
Technician B
Low discharge pressure - high suction pressure - and low amp draw
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
An overcharged system

3. The best description of a relay would be...
Contains a solenoid coil and one or more sets of contacts
A start capacitor and a solid-state relay
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
Broken rings+broken valves+seized bearings

4. A rooftop package system keeps tripping out on the high-pressure switch. What are three possible causes for this problem...
A missing air filter+improper rotation of the indoor blower+blower too small
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Technician A is correct
A defective circuit breaker

5. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
An uninsulated suction line and a restricted metering device
High suction pressure and low superheat
A plugged filter drier
Contains a solenoid coil and one or more sets of contacts

6. What are two problems that can cause an air conditioning system to have an excessively high superheat...
An uninsulated suction line and a restricted metering device
Run with high head and high suction pressure
Contains a solenoid coil and one or more sets of contacts
Lack of airflow

7. On an are-22 air conditioning system - the suction-line filter drier should be changed when the pressure drop dictates...
3 psig
A vacuum test+oil traces around fittings+soap bubble solution
Condenser fans operating during a low ambient condition and a low suction pressure
Rise more than normal

8. What are two common problems that can cause a sight glass in an air conditioning to have bubbles...
An undercharge and low ambient conditions
The external equalizer could be plugged
20 to 30
Run with high head and high suction pressure

9. What is the common cause of a compressor burnout...
Technician B
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Current in the compressor circuit
('Y' and 'C') and ('G' and 'C')

10. What component is most often the cause of a start capacitor failure...
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
Short cycling and insufficient dehumidification
A start relay
Lack of airflow

11. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...
Run with high head and high suction pressure
Low superheat
The oil pump pressure and the crankcase pressure
3 psig

12. The temperature range of the suction line from an air conditioning system should be...
Dirty condenser - bent condenser fins - and air recirculating over the condenser
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
50-65
The superheat will increase and the low-side pressure will decrease

13. What is the purpose of a CPR valve...
Technician B
An open internal overload protector
Technician B
It is used to control refrigerant pressure in the compressor crankcase

14. A customer calls with an insufficient cooling complaint. Upon arrival to the service call it is found that the system is using are-22 with the high-side pressure at 290 psig and the low-side pressure at 85 psig. The ambient temperature is 85
A sensing bulb improperly connected to the suction line
Technician B
Technician A
'G' to 'C'

15. Which of the following is a common cause of an excessively low superheat on a TXV system...
Low voltage and a faulty start relay
An uninsulated suction line and a restricted metering device
A plugged filter drier
A sensing bulb improperly connected to the suction line

16. 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
50-65
Both technicians are correct
The external equalizer could be plugged
Low discharge pressure - high suction pressure - and low amp draw

17. What are the symptoms of a TXV air conditioning system if it has lost its charge...
Low voltage and a faulty start relay
20 to 30
Low voltage and a faulty start relay
The superheat will increase and the low-side pressure will decrease

18. What are common methods that are used for leak-testing a system...
An open internal overload protector
A vacuum test+oil traces around fittings+soap bubble solution
Low discharge pressure - high suction pressure - and low amp draw
Evaporator and compressor

19. 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
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
Broken rings+broken valves+seized bearings
The internal overload is opened
Both technicians are incorrect

20. 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

21. A technician receives an air conditioning service call stating that the system is operating but isn't cooling properly. When the technician arrives - she notices that the compressor has recently been changed and it is an are-22 system. She checks the
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
An uninsulated TXV sensing bulb
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
The sensing bulb at a lower temperature than the valve body

22. 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
High superheat and low discharge pressure
Technician B
A dirty condenser - recirculation of condenser air - and a defective condenser fan
The superheat will increase and the low-side pressure will decrease

23. A party-store owner tried to adjust the water valve on his water-cooled condensing unit - then he called for assistance from an HVAC/are service technician. It was found that when servicing the unit - the outlet water temperature was too low. Technic
('Y' and 'C') and ('G' and 'C')
Technician B
Broken rings+broken valves+seized bearings
An open internal overload protector

24. When a high-efficiency split air conditioning system has a plugged metering device - what symptoms might occur...
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Technician B
An undercharge and low ambient conditions
A restricted metering device

25. A liquid-charged TXV bulb will...
Always have some liquid present in the bulb and diaphragm
Technician A
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 defective evaporator fan - and an iced-up evaporator coil

26. Which of the following is a possible cause for a compressor to overheat...
A low refrigerant charge
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
An overcharged system
Low discharge pressure - high suction pressure - and low amp draw

27. What is the purpose of an EPR valve...
An increase in suction pressure and an increase in discharge pressure
Bad compressor valve
High superheat and low discharge pressure
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system

28. 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
An undercharge and low ambient conditions
Flooding the condenser - cycling condenser fans - and dampering condenser air
Low voltage and a faulty start relay

29. 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
Bad compressor valve
A restricted metering device
Both technicians are incorrect
An uninsulated suction line and a restricted metering device

30. The best description of a relay would be...
Contains a solenoid coil and one or more sets of contacts
Low discharge pressure - high suction pressure - and low amp draw
An overcharged system
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser

31. What are possible problems that can cause the discharge-line temperature on an air conditioning system to be cool to the touch...
Technician B
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
Broken rings+broken valves+seized bearings
Low superheat

32. What are two common symptoms of an overcharged air conditioning system that uses a capillary-tube-type metering device...
Technician B
Technician B
An increase in suction pressure and an increase in discharge pressure
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay

33. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
50-65
Technician B
A missing air filter+improper rotation of the indoor blower+blower too small
The oil pump pressure and the crankcase pressure

34. Air filters should be replaced...
Both technicians are correct
A start relay
Whenever necessary
The external equalizer could be plugged

35. What causes the automatic expansion valve to close...
Technician B
An increase in low-side pressure
Increases starting torque
Low discharge pressure - high suction pressure - and low amp draw

36. What are three methods for controlling a system's high-side pressure during low ambient conditions...
Both technicians are correct
Both technicians are incorrect
Flooding the condenser - cycling condenser fans - and dampering condenser air
Technician B

37. What type of problems can be caused by an oversized air conditioning system...
The superheat will increase and the low-side pressure will decrease
Short cycling and insufficient dehumidification
It keeps a constant superheat in the evaporator
A vacuum test+oil traces around fittings+soap bubble solution

38. A commercial customer calls on a 90
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
The system has been overcharged+The system has air trapped in the condenser
The low-side pressure will decrease and the evaporator coil will be partially frosted
A low refrigerant charge

39. What is the purpose of an EPR valve...
A start relay
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
('Y' and 'C') and ('G' and 'C')
The discharge pressure increases and the amperage increases

40. What are two common problems that can cause a sight glass in an air conditioning to have bubbles...
An undercharge and low ambient conditions
Flooding the condenser - cycling condenser fans - and dampering condenser air
The oil pump pressure and the crankcase pressure
Dirty condenser - bent condenser fins - and air recirculating over the condenser

41. A hard-start kit consists of...
A start capacitor and a solid-state relay
Both technicians are incorrect
Contains a solenoid coil and one or more sets of contacts
High suction pressure and low superheat

42. What problem can cause an increase of discharge pressure and an increase of suction pressure...
The low-side pressure will decrease and the evaporator coil will be partially frosted
An overcharged system
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
An uninsulated TXV sensing bulb

43. After a compressor motor has been severely burnt - What accessory must be added as an aid to rid the air conditioning system of acid...
It is used to control refrigerant pressure in the compressor crankcase
Flooding the condenser - cycling condenser fans - and dampering condenser air
A restricted metering device
An acid-core suction line drier

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
The superheat increases and the subcooling decreases
Technician B
Increases starting torque
Rise more than normal

45. What is the common cause of a compressor burnout...
Clean the condenser coil
An acid-core suction line drier
('Y' and 'C') and ('G' and 'C')
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser

46. What type of problems can be caused by an oversized air conditioning system...
Clean the condenser coil
It keeps a constant superheat in the evaporator
Short cycling and insufficient dehumidification
The superheat increases and the subcooling decreases

47. A hard-start kit for an air conditioning system...
Increases starting torque
3 psig
An increase of air leakage from ductwork
The external equalizer could be plugged

48. What causes the automatic expansion valve to close...
Low voltage and a faulty start relay
A sensing bulb improperly connected to the suction line
Low superheat
An increase in low-side pressure

49. The internal overload of an air conditioning compressor senses winding temperature and...
Current in the compressor circuit
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Technician A
The internal overload is opened

50. A hard-start kit for an air conditioning system...
A blown fuse
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
Increases starting torque
The oil pump pressure and the crankcase pressure