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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. 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
'G' to 'C'
An acid-core suction line drier
Dirty condenser - bent condenser fins - and air recirculating over the condenser

2. 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
Technician B
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Flooding the condenser - cycling condenser fans - and dampering condenser air
Clean the condenser coil

3. Which of the following is a possible cause for a compressor to overheat...
The external equalizer could be plugged
('Y' and 'C') and ('G' and 'C')
A low refrigerant charge
The oil pump pressure and the crankcase pressure

4. 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
Technician B
'G' to 'C'
An increase in suction pressure and an increase in discharge pressure
('Y' and 'C') and ('G' and 'C')

5. A restricted air filter in an air conditioning system can be identified by...
Low superheat
It would cause the low-side pressure to decrease
Run with high head and high suction pressure
Technician B

6. When an air conditioning system has an undercharge - what happens to the superheat and the subcooling of the system...
The superheat increases and the subcooling decreases
'G' to 'C'
An overcharged system
An overcharged system

7. What problem or problems can cause low discharge and suction pressure...
An undercharged system+insufficient airflow over the evaporator coil
110-120
Technician A
It keeps a constant superheat in the evaporator

8. A hard-start kit consists of...
It keeps a constant superheat in the evaporator
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
A low refrigerant charge
A start capacitor and a solid-state relay

9. 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
It would cause the low-side pressure to decrease
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
Rise more than normal

10. A customer calls with an insufficient cooling complaint on a 90
Technician B
A start capacitor and a solid-state relay
A dirty condenser - recirculation of condenser air - and a defective condenser fan
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

11. 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

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12. Which of the following can cause excessive subcooling...
An overcharged system
The discharge pressure increases and the amperage increases
Technician B
Dirty condenser - bent condenser fins - and air recirculating over the condenser

13. 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
Contains a solenoid coil and one or more sets of contacts
Technician B
An undercharge and low ambient conditions
Increases starting torque

14. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...
The sight glass is full of liquid+the sight glass is full of gas
Run with high head and high suction pressure
Technician B
Both technicians are incorrect

15. 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
Low voltage and a faulty start relay
Technician B
Technician A is correct

16. What are the symptoms of an air conditioning system that has a low charge...
The low-side pressure will decrease and the evaporator coil will be partially frosted
Technician B
An increase in low-side pressure
Technician B

17. Superheat is found in an air conditioning system in the...
An open internal overload protector
An undercharge and low ambient conditions
Both technicians are incorrect
Evaporator and compressor

18. Air filters should be replaced...
The superheat will increase and the low-side pressure will decrease
Whenever necessary
A vacuum test+oil traces around fittings+soap bubble solution
The superheat will increase and the low-side pressure will decrease

19. 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
Technician B
A blown fuse
An increase of air leakage from ductwork
Lack of airflow

20. On an are-22 air conditioning system - the suction-line filter drier should be changed when the pressure drop dictates...
Low voltage and a faulty start relay
110-120
An increase of air leakage from ductwork
3 psig

21. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
Both technicians are incorrect
A start relay
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
High suction pressure and low superheat

22. A compressor having tight bearings would cause the current value to...
Rise more than normal
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Bad compressor valve
50-65

23. What are two common symptoms of an overcharged air conditioning system that uses a capillary-tube-type metering device...
The internal overload is opened
An increase in suction pressure and an increase in discharge pressure
Technician B
An undercharge and low ambient conditions

24. If a TXV sensing bulb had lost its charge - what effect would this have on the air conditioning system...
High superheat and low discharge pressure
The low-side pressure will decrease and the evaporator coil will be partially frosted
It would cause the low-side pressure to decrease
Whenever necessary

25. 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
Both technicians are incorrect
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Low discharge pressure - high suction pressure - and low amp draw

26. What are the symptoms of an air conditioning system that has a bad compressor discharge valve...
The sight glass is full of liquid+the sight glass is full of gas
It is used to control refrigerant pressure in the compressor crankcase
The internal overload is opened
Low discharge pressure - high suction pressure - and low amp draw

27. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...
An acid-core suction line drier
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
A restricted metering device
20 to 30

28. What are the symptoms of an air conditioning system that has a low charge...
Both technicians are correct
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
The low-side pressure will decrease and the evaporator coil will be partially frosted
An increase in low-side pressure

29. When testing an indoor blower control circuit and the cooling circuit on a fan center - what terminals should read 24 volts if the air conditioning system is in operation...

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30. A hard-start kit consists of...
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
A start capacitor and a solid-state relay
An undercharge and low ambient conditions

31. 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
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Bad compressor valve
Technician B

32. A hard-start kit for an air conditioning system...
50-65
Increases starting torque
Low superheat
Technician A

33. What three things can prevent an air conditioning system from absorbing heat at the proper rate...
A start relay
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
Both technicians are incorrect

34. What is the purpose of the TXV...
Low voltage and a faulty start relay
The sensing bulb at a lower temperature than the valve body
It is used to control refrigerant pressure in the compressor crankcase
It keeps a constant superheat in the evaporator

35. Which of the following will cause excessive discharge pressures on an air conditioning system...
An increase of air leakage from ductwork
The system has been overcharged+The system has air trapped in the condenser
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor

36. 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...
Short cycling and insufficient dehumidification
('Y' and 'C') and ('G' and 'C')
An undercharged system+insufficient airflow over the evaporator coil
Condenser fans operating during a low ambient condition and a low suction pressure

37. On an are-22 air conditioning system - the suction-line filter drier should be changed when the pressure drop dictates...
3 psig
Whenever necessary
Evaporator and compressor
Low voltage and a faulty start relay

38. 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
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
High superheat and low discharge pressure
An overcharged system
Both technicians are correct

39. Insufficient airflow can be caused by...
A dirty condenser - recirculation of condenser air - and a defective condenser fan
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
An increase of air leakage from ductwork
High suction pressure and low superheat

40. What three things can prevent an air conditioning system from absorbing heat at the proper rate...
A dirty condenser - recirculation of condenser air - and a defective condenser fan
Technician B
An acid-core suction line drier
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

41. A rooftop package system keeps tripping out on the high-pressure switch. What are three possible causes for this problem...
Whenever necessary
A bad thermostat
High suction pressure and low superheat
Dirty condenser - bent condenser fins - and air recirculating over the condenser

42. A compressor having tight bearings would cause the current value to...
Rise more than normal
High suction pressure and low superheat
Low superheat
It would cause the low-side pressure to decrease

43. Which of the following is a common cause of an excessively low superheat on a TXV system...
A plugged filter drier
A sensing bulb improperly connected to the suction line
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
The external equalizer could be plugged

44. A system that is operating with a clear sight glass shows...
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
A low refrigerant charge
Rise more than normal
The sight glass is full of liquid+the sight glass is full of gas

45. What is the common cause of a compressor burnout...
An uninsulated suction line and a restricted metering device
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Technician B
It keeps a constant superheat in the evaporator

46. 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
Current in the compressor circuit
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged

47. Why is it unsafe to operate an air conditioning system with a low charge...
It would cause the low-side pressure to decrease
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
An overcharged system
An uninsulated suction line and a restricted metering device

48. 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
Technician A
It keeps a constant superheat in the evaporator
A low refrigerant charge
Technician B

49. What is the purpose of a CPR valve...
An undercharge and low ambient conditions
It is used to control refrigerant pressure in the compressor crankcase
Current in the compressor circuit
3 psig

50. What are the symptoms of a TXV air conditioning system if it has lost its charge...
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
The superheat will increase and the low-side pressure will decrease
The sensing bulb at a lower temperature than the valve body
A defective circuit breaker