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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 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
Broken rings+broken valves+seized bearings
The low-side pressure will decrease and the evaporator coil will be partially frosted
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Technician B

2. What are the symptoms of an air conditioning system that has a low charge...
An overcharged system
Technician B
20 to 30
The low-side pressure will decrease and the evaporator coil will be partially frosted

3. What type of problems can be caused by an oversized air conditioning system...
Low superheat
Rise more than normal
Short cycling and insufficient dehumidification
An overcharged system

4. Superheat is found in an air conditioning system in the...
Lack of airflow
Evaporator and compressor
A start capacitor and a solid-state relay
Always have some liquid present in the bulb and diaphragm

5. 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
Low superheat
A plugged filter drier
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system

6. After a compressor motor has been severely burnt - What accessory must be added as an aid to rid the air conditioning system of acid...
Both technicians are incorrect
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Technician A is correct
An acid-core suction line drier

7. 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
It keeps a constant superheat in the evaporator
An overcharged system
The low-side pressure will decrease and the evaporator coil will be partially frosted

8. What are two problems that can cause an air conditioning system to have an excessively high superheat...
Low superheat
3 psig
Technician A is correct
An uninsulated suction line and a restricted metering device

9. 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
A plugged filter drier
An increase in low-side pressure
A restricted metering device

10. After a compressor motor has been severely burnt - What accessory must be added as an aid to rid the air conditioning system of acid...
3 psig
An acid-core suction line drier
A restricted metering device
An open internal overload protector

11. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...
A bad thermostat
Broken rings+broken valves+seized bearings
'G' to 'C'
20 to 30

12. What controls are used on air conditioning or refrigeration systems that incorporate an automatic pump-down system...
An uninsulated TXV sensing bulb
The discharge pressure increases and the amperage increases
Technician A is correct
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor

13. When an air conditioning system has an undercharge - what happens to the superheat and the subcooling of the system...
3 psig
Technician B
Run with high head and high suction pressure
The superheat increases and the subcooling decreases

14. The best description of a relay would be...
An increase in suction pressure and an increase in discharge pressure
Contains a solenoid coil and one or more sets of contacts
Low discharge pressure - high suction pressure - and low amp draw
It keeps a constant superheat in the evaporator

15. Which of the following is a possible cause for a compressor to overheat...
A low refrigerant charge
Lack of airflow
Increases starting torque
An undercharge and low ambient conditions

16. Which of the following is a possible cause for a compressor to overheat...
Clean the condenser coil
An open internal overload protector
A low refrigerant charge
Technician B

17. A compressor having tight bearings would cause the current value to...
An acid-core suction line drier
Rise more than normal
A bad thermostat
An undercharge and low ambient conditions

18. What are possible problems that can cause the discharge-line temperature on an air conditioning system to be cool to the touch...
The internal overload is opened
Bad compressor valve
A dirty condenser - recirculation of condenser air - and a defective condenser fan
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device

19. Which of the following can cause low superheat in a TXV system...
An uninsulated TXV sensing bulb
The sensing bulb at a lower temperature than the valve body
A defective circuit breaker
Lack of airflow

20. A liquid-charged TXV bulb will...
Low superheat
An open internal overload protector
An overcharged system
Always have some liquid present in the bulb and diaphragm

21. When using a vapor-charged TXV bulb - it is necessary to have...
The system has been overcharged+The system has air trapped in the condenser
Both technicians are incorrect
The sensing bulb at a lower temperature than the valve body
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system

22. The temperature range of the suction line from an air conditioning system should be...
Low discharge pressure - high suction pressure - and low amp draw
50-65
An increase in low-side pressure
A vacuum test+oil traces around fittings+soap bubble solution

23. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
High suction pressure and low superheat
The discharge pressure increases and the amperage increases
Clean the condenser coil
The sight glass is full of liquid+the sight glass is full of gas

24. 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
An increase of air leakage from ductwork
Rise more than normal
An open internal overload protector

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
An uninsulated TXV sensing bulb
It keeps a constant superheat in the evaporator
A missing air filter+improper rotation of the indoor blower+blower too small
Technician B

26. What type of problems can be caused by an oversized air conditioning system...
Technician B
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
High suction pressure and low superheat
Short cycling and insufficient dehumidification

27. 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
Technician B
The discharge pressure increases and the amperage increases
Both technicians are incorrect

28. On an are-22 air conditioning system - the suction-line filter drier should be changed when the pressure drop dictates...
Increases starting torque
High suction pressure and low superheat
3 psig
An increase of air leakage from ductwork

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
Both technicians are incorrect
Partially frosted evaporator and high superheat
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Partially frosted evaporator and high superheat

30. A hard-start kit for an air conditioning system...
A dirty condenser - recirculation of condenser air - and a defective condenser fan
A restricted metering device
Flooding the condenser - cycling condenser fans - and dampering condenser air
Increases starting torque

31. What problem or problems can cause low discharge and suction pressure...
An increase of air leakage from ductwork
The sensing bulb at a lower temperature than the valve body
Both technicians are incorrect
An undercharged system+insufficient airflow over the evaporator coil

32. What are two common symptoms of an overcharged air conditioning system that uses a capillary-tube-type metering device...
Both technicians are incorrect
('Y' and 'C') and ('G' and 'C')
An increase in suction pressure and an increase in discharge pressure
A dirty condenser - recirculation of condenser air - and a defective condenser fan

33. The temperature range of the suction line from an air conditioning system should be...
The sensing bulb at a lower temperature than the valve body
Condenser fans operating during a low ambient condition and a low suction pressure
Clean the condenser coil
50-65

34. If a TXV sensing bulb had lost its charge - what effect would this have on the air conditioning system...
It would cause the low-side pressure to decrease
Partially frosted evaporator and high superheat
Contains a solenoid coil and one or more sets of contacts
An increase of air leakage from ductwork

35. What is the purpose of an EPR valve...
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Technician A
An acid-core suction line drier
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

36. 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...
A start relay
Low voltage and a faulty start relay
It is used to control refrigerant pressure in the compressor crankcase
The sensing bulb at a lower temperature than the valve body

37. What are two common symptoms of refrigerant leaks in an air conditioning system...
Partially frosted evaporator and high superheat
A missing air filter+improper rotation of the indoor blower+blower too small
110-120
Clean the condenser coil

38. 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
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Technician B
An undercharged system+insufficient airflow over the evaporator coil
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay

39. A 220-volt 30-amp motor circuit keeps tripping the breaker after the motor is started. The starting amperage is 60 amps. When measuring the amperage of the circuit - This is drawn for a brief moment. After startup - the amperage drops to 22 amps and
Rise more than normal
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
A defective circuit breaker

40. What are the symptoms of a TXV air conditioning system if it has lost its charge...
An overcharged system
The superheat will increase and the low-side pressure will decrease
A plugged filter drier
Dirty condenser - bent condenser fins - and air recirculating over the condenser

41. What is the purpose of an EPR valve...
High superheat and low discharge pressure
A blown fuse
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
The oil pump pressure and the crankcase pressure

42. 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
Whenever necessary
Increases starting torque
Technician B
The external equalizer could be plugged

43. 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
An overcharged system
A defective circuit breaker
An overcharged system
The external equalizer could be plugged

44. 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
Lack of airflow
High suction pressure and low superheat
('Y' and 'C') and ('G' and 'C')

45. What are the operating pressures of an oil pressure safety switch...
An increase of air leakage from ductwork
A restricted metering device
Short cycling and insufficient dehumidification
The oil pump pressure and the crankcase pressure

46. What are three methods for controlling a system's high-side pressure during low ambient conditions...
An uninsulated TXV sensing bulb
It would cause the low-side pressure to decrease
The superheat increases and the subcooling decreases
Flooding the condenser - cycling condenser fans - and dampering condenser air

47. A customer calls with an insufficient cooling complaint on a 90
An overcharged system
A blown fuse
Technician B
An uninsulated TXV sensing bulb

48. What are two common problems that can cause a sight glass in an air conditioning to have bubbles...
An overcharged system
An undercharge and low ambient conditions
Technician B
A defective circuit breaker

49. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
The discharge pressure increases and the amperage increases
Increases starting torque
The superheat increases and the subcooling decreases

50. What is the common cause of a compressor burnout...
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
A missing air filter+improper rotation of the indoor blower+blower too small
Low discharge pressure - high suction pressure - and low amp draw
Broken rings+broken valves+seized bearings