Test your basic knowledge |

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. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
Low superheat
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Flooding the condenser - cycling condenser fans - and dampering condenser air
The discharge pressure increases and the amperage increases

2. 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
An uninsulated TXV sensing bulb
Both technicians are incorrect
High suction pressure and low superheat

3. What are possible problems that can cause the discharge-line temperature on an air conditioning system to be cool to the touch...
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
The superheat increases and the subcooling decreases
Technician A is correct
110-120

4. The technician observes a pressure drop of 25 degrees across an air conditioning evaporator coil at start-up. This drop would indicate...
50-65
Lack of airflow
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
Always have some liquid present in the bulb and diaphragm

5. A compressor having tight bearings would cause the current value to...
Rise more than normal
An acid-core suction line drier
Both technicians are correct
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication

6. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...
Low voltage and a faulty start relay
The superheat will increase and the low-side pressure will decrease
Run with high head and high suction pressure
3 psig

7. What are two problems that can cause an air conditioning system to have an excessively high superheat...
A bad thermostat
An uninsulated suction line and a restricted metering device
Condenser fans operating during a low ambient condition and a low suction pressure
A sensing bulb improperly connected to the suction line

8. What are the symptoms of a TXV air conditioning system if it has lost its charge...
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
The external equalizer could be plugged
The discharge pressure increases and the amperage increases

9. 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...
A restricted metering device
The discharge pressure increases and the amperage increases
An acid-core suction line drier
A blown fuse

10. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Technician B
Bad compressor valve
High suction pressure and low superheat

11. A system that is operating with a clear sight glass shows...
The sight glass is full of liquid+the sight glass is full of gas
A bad thermostat
3 psig
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

12. 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

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183

13. What are common methods that are used for leak-testing a system...
Lack of airflow
20 to 30
The superheat increases and the subcooling decreases
A vacuum test+oil traces around fittings+soap bubble solution

14. 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
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
Both technicians are correct

15. 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...
A blown fuse
Technician B
A vacuum test+oil traces around fittings+soap bubble solution
Whenever necessary

16. What is the common cause of a compressor burnout...
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
The internal overload is opened
An undercharged system+insufficient airflow over the evaporator coil
The oil pump pressure and the crankcase pressure

17. What are the operating pressures of an oil pressure safety switch...
An uninsulated suction line and a restricted metering device
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
Flooding the condenser - cycling condenser fans - and dampering condenser air

18. What component is most often the cause of a start capacitor failure...
A start relay
Technician B
Flooding the condenser - cycling condenser fans - and dampering condenser air
3 psig

19. A hard-start kit for an air conditioning system...
Increases starting torque
An acid-core suction line drier
Both technicians are correct
Flooding the condenser - cycling condenser fans - and dampering condenser air

20. What is a common discharge temperature of an air-cooled air conditioning system that is used on a 90
Run with high head and high suction pressure
An increase in suction pressure and an increase in discharge pressure
Technician B
110-120

21. What are two common symptoms of refrigerant leaks in an air conditioning system...
Low discharge pressure - high suction pressure - and low amp draw
Partially frosted evaporator and high superheat
High superheat and low discharge pressure
Technician B

22. When using a vapor-charged TXV bulb - it is necessary to have...
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
The sensing bulb at a lower temperature than the valve body
Technician A
A vacuum test+oil traces around fittings+soap bubble solution

23. Which of the following will cause excessive discharge pressures on an air conditioning system...
The oil pump pressure and the crankcase pressure
High superheat and low discharge pressure
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

24. A customer calls with an insufficient cooling complaint on a 90
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
110-120
Technician B
Evaporator and compressor

25. What are the symptoms of an air conditioning system that has a bad compressor discharge valve...
A defective circuit breaker
The discharge pressure increases and the amperage increases
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Low discharge pressure - high suction pressure - and low amp draw

26. 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
An open internal overload protector
Low voltage and a faulty start relay
50-65

27. What is the purpose of a CPR valve...
Evaporator and compressor
Technician B
It is used to control refrigerant pressure in the compressor crankcase
Low discharge pressure - high suction pressure - and low amp draw

28. A hard-start kit for an air conditioning system...
It would cause the low-side pressure to decrease
A restricted metering device
Increases starting torque
A start capacitor and a solid-state relay

29. What is a possible cause of a sweat or frost pattern downstream from a sight glass and filter dryer...
A sensing bulb improperly connected to the suction line
3 psig
Contains a solenoid coil and one or more sets of contacts
A plugged filter drier

30. 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 correct
A start relay
110-120

31. A system that uses a thermal electric expansion valve...
Technician B
The low-side pressure will decrease and the evaporator coil will be partially frosted
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
The superheat increases and the subcooling decreases

32. Why is it unsafe to operate an air conditioning system with a low charge...
Bad compressor valve
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
Both technicians are incorrect
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged

33. What are two common problems that can cause a sight glass in an air conditioning to have bubbles...
An undercharged system+insufficient airflow over the evaporator coil
An undercharge and low ambient conditions
Broken rings+broken valves+seized bearings
Technician B

34. The internal overload of an air conditioning compressor senses winding temperature and...
The superheat will increase and the low-side pressure will decrease
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Current in the compressor circuit
Condenser fans operating during a low ambient condition and a low suction pressure

35. 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...
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
High superheat and low discharge pressure
Technician B
It keeps a constant superheat in the evaporator

36. Which of the following is a common cause of an excessively low superheat on a TXV system...
It is used to control refrigerant pressure in the compressor crankcase
A sensing bulb improperly connected to the suction line
Partially frosted evaporator and high superheat
Flooding the condenser - cycling condenser fans - and dampering condenser air

37. A compressor having tight bearings would cause the current value to...
Rise more than normal
An overcharged system
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
Technician B

38. Which of the following could be the cause for a system's discharge and suction pressure being low...
A restricted metering device
It would cause the low-side pressure to decrease
Flooding the condenser - cycling condenser fans - and dampering condenser air
Technician B

39. 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...
50-65
Both technicians are correct
The internal overload is opened
An increase in suction pressure and an increase in discharge pressure

40. A hard-start kit consists of...
The superheat will increase and the low-side pressure will decrease
('Y' and 'C') and ('G' and 'C')
A start capacitor and a solid-state relay
110-120

41. What are the symptoms of an air conditioning system that has a low charge...
A bad thermostat
The low-side pressure will decrease and the evaporator coil will be partially frosted
The external equalizer could be plugged
A start relay

42. A commercial customer calls on a 90
Increases starting torque
A bad thermostat
A start relay
The system has been overcharged+The system has air trapped in the condenser

43. On an are-22 air conditioning system - the suction-line filter drier should be changed when the pressure drop dictates...
A start capacitor and a solid-state relay
3 psig
Increases starting torque
Partially frosted evaporator and high superheat

44. 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

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183

45. 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
Flooding the condenser - cycling condenser fans - and dampering condenser air
Both technicians are incorrect
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

46. 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...
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
'G' to 'C'
Condenser fans operating during a low ambient condition and a low suction pressure
An overcharged system

47. A restricted air filter in an air conditioning system can be identified by...
The sensing bulb at a lower temperature than the valve body
The external equalizer could be plugged
Low superheat
The system has been overcharged+The system has air trapped in the condenser

48. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
A missing air filter+improper rotation of the indoor blower+blower too small
Technician A is correct
Technician B

49. An air conditioning unit has a suction line that is frosted up to the compressor. What faults could cause this to occur...
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Technician B
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system

50. 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 dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
A start relay
Technician B
An increase in low-side pressure