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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. The best description of a relay would be...
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
Contains a solenoid coil and one or more sets of contacts
A bad thermostat
Low superheat

2. 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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3. The temperature range of the suction line from an air conditioning system should be...
An undercharge and low ambient conditions
50-65
A defective circuit breaker
Technician B

4. A restricted air filter in an air conditioning system can be identified by...
Low superheat
A restricted metering device
The oil pump pressure and the crankcase pressure
Low discharge pressure - high suction pressure - and low amp draw

5. 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
An increase in suction pressure and an increase in discharge pressure
A bad thermostat
Technician B
An undercharge and low ambient conditions

6. A liquid-charged TXV bulb will...
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Always have some liquid present in the bulb and diaphragm
Evaporator and compressor
Whenever necessary

7. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
The oil pump pressure and the crankcase pressure
High suction pressure and low superheat
Technician B
110-120

8. 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
The superheat increases and the subcooling decreases
A low refrigerant charge
Partially frosted evaporator and high superheat

9. After a compressor motor has been severely burnt - What accessory must be added as an aid to rid the air conditioning system of acid...
Technician B
An overcharged system
An acid-core suction line drier
50-65

10. Superheat is found in an air conditioning system in the...
Lack of airflow
Both technicians are incorrect
The superheat increases and the subcooling decreases
Evaporator and compressor

11. What causes the automatic expansion valve to close...
An increase in low-side pressure
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
Condenser fans operating during a low ambient condition and a low suction pressure
50-65

12. 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
An undercharged system+insufficient airflow over the evaporator coil
Technician B
Bad compressor valve

13. What causes the automatic expansion valve to close...
A defective circuit breaker
An overcharged system
An increase in low-side pressure
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor

14. What are two common symptoms of refrigerant leaks in an air conditioning system...
Technician B
A restricted metering device
Technician A
Partially frosted evaporator and high superheat

15. What are the symptoms of an air conditioning system that has a low charge...
Flooding the condenser - cycling condenser fans - and dampering condenser air
The low-side pressure will decrease and the evaporator coil will be partially frosted
Low voltage and a faulty start relay
20 to 30

16. 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
An open internal overload protector
A defective circuit breaker
50-65
Rise more than normal

17. The best description of a relay would be...
Contains a solenoid coil and one or more sets of contacts
Flooding the condenser - cycling condenser fans - and dampering condenser air
Technician B
A missing air filter+improper rotation of the indoor blower+blower too small

18. 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...
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
A blown fuse
The discharge pressure increases and the amperage increases
A defective circuit breaker

19. What are the symptoms of a TXV air conditioning system if it has lost its charge...
The system has been overcharged+The system has air trapped in the condenser
The superheat will increase and the low-side pressure will decrease
Increases starting torque
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

20. 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
Technician B
The sight glass is full of liquid+the sight glass is full of gas
Rise more than normal
A blown fuse

21. 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
A dirty condenser - recirculation of condenser air - and a defective condenser fan
The superheat increases and the subcooling decreases
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
Both technicians are incorrect

22. 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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23. Which of the following can cause low superheat in a TXV system...
The oil pump pressure and the crankcase pressure
An uninsulated TXV sensing bulb
Both technicians are incorrect
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

24. Which of the following could be the cause for a system's discharge and suction pressure being low...
A restricted metering device
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
Current in the compressor circuit
A plugged filter drier

25. Which of the following could be the cause for a system's discharge and suction pressure being low...
A restricted metering device
Technician B
The superheat will increase and the low-side pressure will decrease
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

26. 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
Contains a solenoid coil and one or more sets of contacts
Run with high head and high suction pressure
Both technicians are incorrect

27. 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...
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Condenser fans operating during a low ambient condition and a low suction pressure
Low voltage and a faulty start relay
Both technicians are incorrect

28. 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
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Technician B
The superheat will increase and the low-side pressure will decrease

29. A system that uses a thermal electric expansion valve...
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
20 to 30
Low discharge pressure - high suction pressure - and low amp draw
Technician B

30. A hard-start kit consists of...
It is used to control refrigerant pressure in the compressor crankcase
An uninsulated suction line and a restricted metering device
A start capacitor and a solid-state relay
Technician B

31. What are two common problems that can cause a sight glass in an air conditioning to have bubbles...
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
An undercharge and low ambient conditions
Increases starting torque
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system

32. What are common methods that are used for leak-testing a system...
A vacuum test+oil traces around fittings+soap bubble solution
50-65
3 psig
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system

33. 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
The superheat will increase and the low-side pressure will decrease
A defective circuit breaker
An overcharged system
A vacuum test+oil traces around fittings+soap bubble solution

34. A hard-start kit for an air conditioning system...
A low refrigerant charge
An overcharged system
A restricted metering device
Increases starting torque

35. 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
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Clean the condenser coil
Technician A is correct
Technician B

36. A rooftop package system keeps tripping out on the high-pressure switch. What are three possible causes for this problem...
Dirty condenser - bent condenser fins - and air recirculating over 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 dirty evaporator coil+a plugged air filter+a bad indoor blower relay
An increase of air leakage from ductwork

37. What is the purpose of an EPR valve...
The superheat increases and the subcooling decreases
An overcharged system
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Technician B

38. What are the symptoms of an air conditioning system that has a low charge...
An acid-core suction line drier
The low-side pressure will decrease and the evaporator coil will be partially frosted
Rise more than normal
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser

39. 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
It would cause the low-side pressure to decrease
The internal overload is opened
Rise more than normal
Technician B

40. What component is most often the cause of a start capacitor failure...
The discharge pressure increases and the amperage increases
A plugged filter drier
A start relay
('Y' and 'C') and ('G' and 'C')

41. Which of the following is a possible cause for a compressor to overheat...
A start relay
A low refrigerant charge
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Technician A

42. What problem or problems can cause the discharge pressure to be low and the suction pressure to be high...
A start capacitor and a solid-state relay
Bad compressor valve
The discharge pressure increases and the amperage increases
'G' to 'C'

43. A compressor having tight bearings would cause the current value to...
Technician A is correct
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
The superheat increases and the subcooling decreases
Rise more than normal

44. After a compressor motor has been severely burnt - What accessory must be added as an aid to rid the air conditioning system of acid...
An acid-core suction line drier
The low-side pressure will decrease and the evaporator coil will be partially frosted
Rise more than normal
The low-side pressure will decrease and the evaporator coil will be partially frosted

45. 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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46. 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...
An increase in low-side pressure
A blown fuse
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication

47. What problem or problems can cause low discharge and suction pressure...
An undercharged system+insufficient airflow over the evaporator coil
The low-side pressure will decrease and the evaporator coil will be partially frosted
It is used to control refrigerant pressure in the compressor crankcase
The sensing bulb at a lower temperature than the valve body

48. A compressor having tight bearings would cause the current value to...
110-120
An uninsulated TXV sensing bulb
Rise more than normal
Technician A

49. 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
A plugged filter drier
An overcharged system
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Evaporator and compressor

50. 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
High suction pressure and low superheat
An uninsulated TXV sensing bulb
High suction pressure and low superheat