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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. 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 external equalizer could be plugged
Technician B
Both technicians are incorrect
A sensing bulb improperly connected to the suction line

2. A compressor having tight bearings would cause the current value to...
Technician A
Rise more than normal
An overcharged system
Technician B

3. Why is it unsafe to operate an air conditioning system with a low charge...
The internal overload is opened
Both technicians are incorrect
An increase in suction pressure and an increase in discharge pressure
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication

4. 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
Partially frosted evaporator and high superheat
A bad thermostat
Technician B

5. 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
A missing air filter+improper rotation of the indoor blower+blower too small
Short cycling and insufficient dehumidification
Clean the condenser coil
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system

6. What is a common discharge temperature of an air-cooled air conditioning system that is used on a 90
3 psig
A vacuum test+oil traces around fittings+soap bubble solution
110-120
Technician B

7. 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
Broken rings+broken valves+seized bearings
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
Both technicians are incorrect

8. 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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9. When a high-efficiency split air conditioning system has a plugged metering device - what symptoms might occur...
A vacuum test+oil traces around fittings+soap bubble solution
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Technician B
Low superheat

10. A hard-start kit for an air conditioning system...
Increases starting torque
Contains a solenoid coil and one or more sets of contacts
A dirty condenser - recirculation of condenser air - and a defective condenser fan
Dirty condenser - bent condenser fins - and air recirculating over the condenser

11. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
A missing air filter+improper rotation of the indoor blower+blower too small
The discharge pressure increases and the amperage increases
Contains a solenoid coil and one or more sets of contacts
A restricted metering device

12. Which of the following is a possible cause for a compressor to overheat...
Technician B
A low refrigerant charge
The sensing bulb at a lower temperature than the valve body
An overcharged system

13. 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
Technician B
Broken rings+broken valves+seized bearings
3 psig
Technician A

14. If 24 volts are present to the contactor coil on an air conditioning system and the condenser fan or compressor is inoperative - which of the following could be at fault...
Run with high head and high suction pressure
Technician B
A sensing bulb improperly connected to the suction line
A blown fuse

15. 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
Clean the condenser coil
The external equalizer could be plugged
'G' to 'C'
Technician B

16. What is the purpose of a CPR valve...
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
It keeps a constant superheat in the evaporator
It is used to control refrigerant pressure in the compressor crankcase
A restricted metering device

17. 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
Technician A
Low discharge pressure - high suction pressure - and low amp draw
Broken rings+broken valves+seized bearings
An overcharged system

18. When an air conditioning system has an undercharge - what happens to the superheat and the subcooling of the system...
It keeps a constant superheat in the evaporator
Both technicians are incorrect
A blown fuse
The superheat increases and the subcooling decreases

19. What three things can prevent an air conditioning system from absorbing heat at the proper rate...
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
High suction pressure and low superheat
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

20. An air conditioning unit has a suction line that is frosted up to the compressor. What faults could cause this to occur...
A sensing bulb improperly connected to the suction line
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
The low-side pressure will decrease and the evaporator coil will be partially frosted
The discharge pressure increases and the amperage increases

21. What is the purpose of an EPR valve...
'G' to 'C'
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Technician B
The sensing bulb at a lower temperature than the valve body

22. Which of the following can cause low superheat in a TXV system...
High suction pressure and low superheat
A bad thermostat
An uninsulated TXV sensing bulb
Technician A is correct

23. A liquid-charged TXV bulb will...
Partially frosted evaporator and high superheat
A defective circuit breaker
Rise more than normal
Always have some liquid present in the bulb and diaphragm

24. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...
Both technicians are incorrect
A restricted metering device
20 to 30
50-65

25. A customer calls with an insufficient cooling complaint on a 90
The internal overload is opened
Technician B
Bad compressor valve
It would cause the low-side pressure to decrease

26. A liquid-charged TXV bulb will...
Always have some liquid present in the bulb and diaphragm
Technician B
Both technicians are incorrect
Technician A

27. A hard-start kit consists of...
3 psig
A start capacitor and a solid-state relay
An uninsulated suction line and a restricted metering device
20 to 30

28. The technician observes that the compressor is not operating. The compressor windings read 5 ohms start to run - run to common is opened - and start to common is opened. The technician concludes that...
Low voltage and a faulty start relay
A defective circuit breaker
The internal overload is opened
Technician A is correct

29. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
Flooding the condenser - cycling condenser fans - and dampering condenser air
A defective circuit breaker
High suction pressure and low superheat
An uninsulated suction line and a restricted metering device

30. The best description of a relay would be...
A vacuum test+oil traces around fittings+soap bubble solution
High superheat and low discharge pressure
Contains a solenoid coil and one or more sets of contacts
Dirty condenser - bent condenser fins - and air recirculating over the condenser

31. Which of the following can cause low superheat in a TXV system...
Evaporator and compressor
An uninsulated TXV sensing bulb
A plugged filter drier
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

32. A hard-start kit for an air conditioning system...
Technician A is correct
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
Technician B

33. Superheat is found in an air conditioning system in the...
High suction pressure and low superheat
An acid-core suction line drier
Low superheat
Evaporator and compressor

34. Which of the following can cause excessive subcooling...
An overcharged system
An increase in low-side pressure
An increase of air leakage from ductwork
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication

35. What are the symptoms of a TXV air conditioning system if it has lost its charge...
Run with high head and high suction 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

36. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
A start relay
The superheat will increase and the low-side pressure will decrease
The oil pump pressure and the crankcase pressure
The discharge pressure increases and the amperage increases

37. What three things can prevent an air conditioning system from absorbing heat at the proper rate...
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
An uninsulated TXV sensing bulb
A start capacitor and a solid-state relay
Both technicians are correct

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
The sight glass is full of liquid+the sight glass is full of gas
An increase in suction pressure and an increase in discharge pressure
An uninsulated TXV sensing bulb

39. What problem or problems can cause the discharge pressure to be low and the suction pressure to be high...
Bad compressor valve
An overcharged system
The external equalizer could be plugged
The low-side pressure will decrease and the evaporator coil will be partially frosted

40. 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
The system has been overcharged+The system has air trapped in the condenser
The oil pump pressure and the crankcase pressure
Both technicians are incorrect

41. The technician observes that the compressor is not operating. The compressor windings read 5 ohms start to run - run to common is opened - and start to common is opened. The technician concludes that...
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
The internal overload is opened
A dirty condenser - recirculation of condenser air - and a defective condenser fan
Technician A

42. 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
The external equalizer could be plugged
It keeps a constant superheat in the evaporator
Technician B
Short cycling and insufficient dehumidification

43. The technician observes a pressure drop of 25 degrees across an air conditioning evaporator coil at start-up. This drop would indicate...
The external equalizer could be plugged
High suction pressure and low superheat
20 to 30
Lack of airflow

44. The temperature range of the suction line from an air conditioning system should be...
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
A missing air filter+improper rotation of the indoor blower+blower too small
50-65

45. 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
A defective circuit breaker
It is used to control refrigerant pressure in the compressor crankcase
('Y' and 'C') and ('G' and 'C')
The sight glass is full of liquid+the sight glass is full of gas

46. What are two common problems that can cause a sight glass in an air conditioning to have bubbles...
'G' to 'C'
An undercharge and low ambient conditions
Technician B
An increase in low-side pressure

47. 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
Technician B
Both technicians are incorrect
An undercharged system+insufficient airflow over the evaporator coil
Both technicians are correct

48. Insufficient airflow can be caused by...
Always have some liquid present in the bulb and diaphragm
It is used to control refrigerant pressure in the compressor crankcase
An increase of air leakage from ductwork
Short cycling and insufficient dehumidification

49. What problem or problems can cause the discharge pressure to be low and the suction pressure to be high...
A blown fuse
Bad compressor valve
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Current in the compressor circuit

50. An air conditioning system that uses a fan center has an inoperable indoor blower. When the thermostat is set for cooling and dialed below room temperature - a test with the voltmeter shows that there is 24 volts across terminals 'are' and 'G' at the
Lack of airflow
A bad thermostat
An overcharged system
The low-side pressure will decrease and the evaporator coil will be partially frosted