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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. Which of the following is a common cause of an excessively low superheat on a TXV system...
50-65
It keeps a constant superheat in the evaporator
Flooding the condenser - cycling condenser fans - and dampering condenser air
A sensing bulb improperly connected to the suction line

2. When an air conditioning system has an undercharge - what happens to the superheat and the subcooling of the system...
Rise more than normal
The superheat will increase and the low-side pressure will decrease
It keeps a constant superheat in the evaporator
The superheat increases and the subcooling decreases

3. Which of the following is a common cause of an excessively low superheat on a TXV system...
The sight glass is full of liquid+the sight glass is full of gas
Condenser fans operating during a low ambient condition and a low suction pressure
Both technicians are correct
A sensing bulb improperly connected to the suction line

4. 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
110-120
Evaporator and compressor
High suction pressure and low superheat

5. What are three methods for controlling a system's high-side pressure during low ambient conditions...
Flooding the condenser - cycling condenser fans - and dampering condenser air
The external equalizer could be plugged
Always have some liquid present in the bulb and diaphragm
A missing air filter+improper rotation of the indoor blower+blower too small

6. What is the common cause of a compressor burnout...
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
The discharge pressure increases and the amperage increases
The superheat will increase and the low-side pressure will decrease
It keeps a constant superheat in the evaporator

7. 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
('Y' and 'C') and ('G' and 'C')
Technician B
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
High superheat and low discharge pressure

8. A compressor having tight bearings would cause the current value to...
A sensing bulb improperly connected to the suction line
Rise more than normal
Bad compressor valve
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser

9. Which of the following is a possible cause for a compressor to overheat...
A low refrigerant charge
Both technicians are incorrect
The superheat increases and the subcooling decreases
An undercharge and low ambient conditions

10. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...
It keeps a constant superheat in the evaporator
An overcharged system
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
20 to 30

11. A hard-start kit for an air conditioning system...
Increases starting torque
The sight glass is full of liquid+the sight glass is full of gas
Technician A
Technician A is correct

12. Which of the following can cause low superheat in a TXV system...
An uninsulated TXV sensing bulb
110-120
An open internal overload protector
Technician B

13. Which of the following can cause excessive subcooling...
An overcharged system
Low superheat
Technician B
A blown fuse

14. 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
Dirty condenser - bent condenser fins - and air recirculating over the condenser
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
Both technicians are correct
An increase in low-side pressure

15. What is the purpose of the TXV...
It keeps a constant superheat in the evaporator
An overcharged system
Rise more than normal
3 psig

16. What is the purpose of a CPR valve...
The superheat will increase and the low-side pressure will decrease
It is used to control refrigerant pressure in the compressor crankcase
A blown fuse
An increase in low-side pressure

17. On an are-22 air conditioning system - the suction-line filter drier should be changed when the pressure drop dictates...
It would cause the low-side pressure to decrease
3 psig
A dirty condenser - recirculation of condenser air - and a defective condenser fan
Condenser fans operating during a low ambient condition and a low suction pressure

18. After a compressor motor has been severely burnt - What accessory must be added as an aid to rid the air conditioning system of acid...
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
An overcharged system
Both technicians are incorrect
An acid-core suction line drier

19. What problem or problems can cause the discharge pressure to be low and the suction pressure to be high...
110-120
Bad compressor valve
Run with high head and high suction pressure
Technician B

20. What three things can prevent an air conditioning system from releasing heat at the proper rate...
Technician B
Condenser fans operating during a low ambient condition and a low suction pressure
A dirty condenser - recirculation of condenser air - and a defective condenser fan
Technician A

21. 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
Technician B
Low voltage and a faulty start relay
The sight glass is full of liquid+the sight glass is full of gas
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

22. Insufficient airflow can be caused by...
A plugged filter drier
A vacuum test+oil traces around fittings+soap bubble solution
An increase of air leakage from ductwork
An open internal overload protector

23. A restricted air filter in an air conditioning system can be identified by...
Low superheat
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
An uninsulated TXV sensing bulb
The internal overload is opened

24. What are the symptoms of an air conditioning system that has a low charge...
A start relay
Whenever necessary
The low-side pressure will decrease and the evaporator coil will be partially frosted
20 to 30

25. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...
A defective circuit breaker
20 to 30
Rise more than normal
The sight glass is full of liquid+the sight glass is full of gas

26. A rooftop package system keeps tripping out on the high-pressure switch. What are three possible causes for this problem...
A start capacitor and a solid-state relay
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Current in the compressor circuit
20 to 30

27. An air conditioning unit has a suction line that is frosted up to the compressor. What faults could cause this to occur...
It keeps a constant superheat in the evaporator
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Contains a solenoid coil and one or more sets of contacts
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser

28. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
Contains a solenoid coil and one or more sets of contacts
A missing air filter+improper rotation of the indoor blower+blower too small
Both technicians are incorrect
Whenever necessary

29. The temperature range of the suction line from an air conditioning system should be...
An open internal overload protector
The system has been overcharged+The system has air trapped in the condenser
50-65
The discharge pressure increases and the amperage increases

30. What are two problems that can cause an air conditioning system to have an excessively high superheat...
It is used to control refrigerant pressure in the compressor crankcase
Technician A
An uninsulated suction line and a restricted metering device
The superheat will increase and the low-side pressure will decrease

31. What problem can cause an increase of discharge pressure and an increase of suction pressure...
The sensing bulb at a lower temperature than the valve body
A dirty condenser - recirculation of condenser air - and a defective condenser fan
Clean the condenser coil
An overcharged system

32. A compressor having tight bearings would cause the current value to...
Rise more than normal
An open internal overload protector
A restricted metering device
An open internal overload protector

33. What are the operating pressures of an oil pressure safety switch...
The oil pump pressure and the crankcase pressure
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
A missing air filter+improper rotation of the indoor blower+blower too small
('Y' and 'C') and ('G' and 'C')

34. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
A bad thermostat
The discharge pressure increases and the amperage increases
A vacuum test+oil traces around fittings+soap bubble solution
An increase of air leakage from ductwork

35. A hard-start kit consists of...
A low refrigerant charge
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
A start capacitor and a solid-state relay
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system

36. When using a vapor-charged TXV bulb - it is necessary to have...
The sensing bulb at a lower temperature than the valve body
Clean the condenser coil
A blown fuse
Lack of airflow

37. 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
The sensing bulb at a lower temperature than the valve body
'G' to 'C'
Technician B
The oil pump pressure and the crankcase pressure

38. What controls are used on air conditioning or refrigeration systems that incorporate an automatic pump-down system...
Technician B
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
20 to 30
Partially frosted evaporator and high superheat

39. An air conditioning unit has a suction line that is frosted up to the compressor. What faults could cause this to occur...
'G' to 'C'
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Technician A
A missing air filter+improper rotation of the indoor blower+blower too small

40. When an air conditioning system has an undercharge - what happens to the superheat and the subcooling of the system...
Condenser fans operating during a low ambient condition and a low suction pressure
The superheat increases and the subcooling decreases
3 psig
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication

41. 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
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Both technicians are incorrect
Technician A is correct
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser

42. What is a possible cause of a sweat or frost pattern downstream from a sight glass and filter dryer...
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
50-65
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
A plugged filter drier

43. A commercial customer calls on a 90
The sensing bulb at a lower temperature than the valve body
The system has been overcharged+The system has air trapped in the condenser
The external equalizer could be plugged
The sensing bulb at a lower temperature than the valve body

44. 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...
Lack of airflow
Both technicians are correct
A plugged filter drier
Low voltage and a faulty start relay

45. Which of the following could be the cause for a system's discharge and suction pressure being low...
An undercharged system+insufficient airflow over the evaporator coil
Contains a solenoid coil and one or more sets of contacts
Both technicians are incorrect
A restricted metering device

46. A hard-start kit consists of...
Both technicians are incorrect
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
A start capacitor and a solid-state relay
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system

47. Which of the following can cause excessive subcooling...
Low voltage and a faulty start relay
The superheat increases and the subcooling decreases
Flooding the condenser - cycling condenser fans - and dampering condenser air
An overcharged system

48. 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
Low discharge pressure - high suction pressure - and low amp draw
An increase of air leakage from ductwork
Technician B
Increases starting torque

49. What causes the automatic expansion valve to close...
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
An increase in low-side pressure
A restricted metering device
An uninsulated TXV sensing bulb

50. A hard-start kit for an air conditioning system...
Increases starting torque
Low superheat
A low refrigerant charge
A start relay