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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. Why is it unsafe to operate an air conditioning system with a low charge...
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
It is used to control refrigerant pressure in the compressor crankcase
The oil pump pressure and the crankcase pressure
An acid-core suction line drier

2. 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
Bad compressor valve
Low voltage and a faulty start relay
The discharge pressure increases and the amperage increases

3. What are two common symptoms of refrigerant leaks in an air conditioning system...
Clean the condenser coil
Partially frosted evaporator and high superheat
The external equalizer could be plugged
An overcharged system

4. Which of the following is a possible cause for a compressor to overheat...
Broken rings+broken valves+seized bearings
A low refrigerant charge
('Y' and 'C') and ('G' and 'C')
An increase in low-side pressure

5. 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
Always have some liquid present in the bulb and diaphragm
50-65
Evaporator and compressor
Technician B

6. 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
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
An increase in suction pressure and an increase in discharge pressure
It keeps a constant superheat in the evaporator

7. 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
The sensing bulb at a lower temperature than the valve body
A defective circuit breaker
Condenser fans operating during a low ambient condition and a low suction pressure

8. 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
Technician B
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
Always have some liquid present in the bulb and diaphragm
Both technicians are incorrect

9. A system that uses a thermal electric expansion valve...
Bad compressor valve
An increase of air leakage from ductwork
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Technician B

10. What are two common symptoms of an overcharged air conditioning system that uses a capillary-tube-type metering device...
An uninsulated suction line and a restricted metering device
Technician B
An increase in suction pressure and an increase in discharge pressure
Clean the condenser coil

11. What three things can prevent an air conditioning system from releasing heat at the proper rate...
A dirty condenser - recirculation of condenser air - and a defective condenser fan
An acid-core suction line drier
Clean the condenser coil
110-120

12. A customer calls with an insufficient cooling complaint on a 90
Lack of airflow
The superheat increases and the subcooling decreases
Technician B
The internal overload is opened

13. 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
Low discharge pressure - high suction pressure - and low amp draw
The discharge pressure increases and the amperage increases
Technician B
Technician A

14. What problem or problems can cause the discharge pressure to be low and the suction pressure to be high...
Bad compressor valve
'G' to 'C'
An uninsulated suction line and a restricted metering device
A missing air filter+improper rotation of the indoor blower+blower too small

15. 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
A plugged filter drier
It is used to control refrigerant pressure in the compressor crankcase
Broken rings+broken valves+seized bearings
Both technicians are correct

16. A liquid-charged TXV bulb will...
A sensing bulb improperly connected to the suction line
Always have some liquid present in the bulb and diaphragm
High superheat and low discharge pressure
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device

17. What three things can prevent an air conditioning system from absorbing heat at the proper rate...
The internal overload is opened
An increase in suction pressure and an increase in discharge pressure
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
Technician A is correct

18. What is the purpose of a CPR valve...
It is used to control refrigerant pressure in the compressor crankcase
Lack of airflow
Technician B
A vacuum test+oil traces around fittings+soap bubble solution

19. On an are-22 air conditioning system - the suction-line filter drier should be changed when the pressure drop dictates...
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
A sensing bulb improperly connected to the suction line
3 psig
A dirty condenser - recirculation of condenser air - and a defective condenser fan

20. On an are-22 air conditioning system - the suction-line filter drier should be changed when the pressure drop dictates...
3 psig
An increase in suction pressure and an increase in discharge pressure
A defective circuit breaker
Technician B

21. 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
Technician B
The internal overload is opened
3 psig
Rise more than normal

22. After a compressor motor has been severely burnt - What accessory must be added as an aid to rid the air conditioning system of acid...
Increases starting torque
Low voltage and a faulty start relay
Both technicians are incorrect
An acid-core suction line drier

23. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
It would cause the low-side pressure to decrease
An increase in low-side pressure
The discharge pressure increases and the amperage increases
An uninsulated suction line and a restricted metering device

24. A system that uses a thermal electric expansion valve...
A bad thermostat
50-65
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
A start capacitor and a solid-state relay

25. The technician observes a pressure drop of 25 degrees across an air conditioning evaporator coil at start-up. This drop would indicate...
Lack of airflow
A bad thermostat
3 psig
An overcharged system

26. What is a common discharge temperature of an air-cooled air conditioning system that is used on a 90
Rise more than normal
An uninsulated suction line and a restricted metering device
110-120
The superheat will increase and the low-side pressure will decrease

27. A restricted air filter in an air conditioning system can be identified by...
Contains a solenoid coil and one or more sets of contacts
An increase in suction pressure and an increase in discharge pressure
Low superheat
Both technicians are correct

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
Current in the compressor circuit
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system

29. What are three methods for controlling a system's high-side pressure during low ambient conditions...
Whenever necessary
The external equalizer could be plugged
'G' to 'C'
Flooding the condenser - cycling condenser fans - and dampering condenser air

30. 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...
An uninsulated suction line and a restricted metering device
An overcharged system
High superheat and low discharge pressure
It would cause the low-side pressure to decrease

31. A commercial customer calls on a 90
Flooding the condenser - cycling condenser fans - and dampering condenser air
The system has been overcharged+The system has air trapped in the condenser
Partially frosted evaporator and high superheat
Increases starting torque

32. 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
A low refrigerant charge
Technician B
Lack of airflow
110-120

33. A hard-start kit consists of...
Technician A is correct
The sensing bulb at a lower temperature than the valve body
Technician A is correct
A start capacitor and a solid-state relay

34. What are the operating pressures of an oil pressure safety switch...
An overcharged system
A vacuum test+oil traces around fittings+soap bubble solution
The oil pump pressure and the crankcase pressure
Technician A

35. 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...

36. What are possible problems that can cause the discharge-line temperature on an air conditioning system to be cool to the touch...
An increase in suction pressure and an increase in discharge pressure
50-65
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
A sensing bulb improperly connected to the suction line

37. 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
Clean the condenser coil
Rise more than normal
The system has been overcharged+The system has air trapped in the condenser

38. A customer calls to complain that his central air conditioning system is not cooling properly. The technician arrives on the job. He or she notices that the indoor blower has adequate airflow and the outdoor condenser fan is operating - but the compr
The low-side pressure will decrease and the evaporator coil will be partially frosted
Condenser fans operating during a low ambient condition and a low suction pressure
A start relay
An open internal overload protector

39. The internal overload of an air conditioning compressor senses winding temperature and...
Technician A
Both technicians are incorrect
Current in the compressor circuit
Dirty condenser - bent condenser fins - and air recirculating over the condenser

40. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
The discharge pressure increases and the amperage increases
Technician B
Technician B
A missing air filter+improper rotation of the indoor blower+blower too small

41. Which of the following will cause excessive discharge pressures on an air conditioning system...
The external equalizer could be plugged
An increase of air leakage from ductwork
3 psig
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system

42. Insufficient airflow can be caused by...
The system has been overcharged+The system has air trapped in the condenser
An increase of air leakage from ductwork
Technician B
Lack of airflow

43. 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
Both technicians are incorrect
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
110-120
Run with high head and high suction pressure

44. Which of the following can cause excessive subcooling...
An overcharged system
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Condenser fans operating during a low ambient condition and a low suction pressure
A sensing bulb improperly connected to the suction line

45. The temperature range of the suction line from an air conditioning system should be...
The superheat will increase and the low-side pressure will decrease
50-65
An increase in suction pressure and an increase in discharge pressure
Evaporator and compressor

46. What problem can cause an increase of discharge pressure and an increase of suction pressure...
Technician B
An overcharged system
An acid-core suction line drier
Technician A

47. What are the symptoms of an air conditioning system that has a bad compressor discharge valve...
Lack of airflow
Low discharge pressure - high suction pressure - and low amp draw
Whenever necessary
An acid-core suction line drier

48. What problem or problems can cause low discharge and suction pressure...
Condenser fans operating during a low ambient condition and a low suction pressure
The low-side pressure will decrease and the evaporator coil will be partially frosted
The superheat will increase and the low-side pressure will decrease
An undercharged system+insufficient airflow over the evaporator coil

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
The external equalizer could be plugged
'G' to 'C'

50. 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...