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. What are possible problems that can cause the discharge-line temperature on an air conditioning system to be cool to the touch...
A plugged filter drier
Lack of airflow
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
Low voltage and a faulty start relay

2. 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
Technician B
Technician A
An open internal overload protector
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor

3. What are two common symptoms of an overcharged air conditioning system that uses a capillary-tube-type metering device...
An uninsulated TXV sensing bulb
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
Low voltage and a faulty start relay
An increase in suction pressure and an increase in discharge pressure

4. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
Both technicians are correct
Current in the compressor circuit
Current in the compressor circuit
A missing air filter+improper rotation of the indoor blower+blower too small

5. What are the symptoms of an air conditioning system that has a bad compressor discharge valve...
Whenever necessary
Low discharge pressure - high suction pressure - and low amp draw
50-65
An undercharged system+insufficient airflow over the evaporator coil

6. 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
Run with high head and high suction pressure
An open internal overload protector
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Partially frosted evaporator and high superheat

7. A compressor having tight bearings would cause the current value to...
Technician B
The superheat increases and the subcooling decreases
Rise more than normal
An increase in low-side pressure

8. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...
Run with high head and high suction pressure
3 psig
A defective circuit breaker
The superheat will increase and the low-side pressure will decrease

9. A commercial customer calls on a 90
The system has been overcharged+The system has air trapped in the condenser
The internal overload is opened
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
Partially frosted evaporator and high superheat

10. The temperature range of the suction line from an air conditioning system should be...
A low refrigerant charge
A plugged filter drier
A missing air filter+improper rotation of the indoor blower+blower too small
50-65

11. What is a possible cause of a sweat or frost pattern downstream from a sight glass and filter dryer...
A plugged filter drier
Technician A
Bad compressor valve
An increase of air leakage from ductwork

12. 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
Broken rings+broken valves+seized bearings
A restricted metering device
Technician B
The sensing bulb at a lower temperature than the valve body

13. 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
A bad thermostat
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
Technician B
An uninsulated TXV sensing bulb

14. What problem or problems can cause the discharge pressure to be low and the suction pressure to be high...
The external equalizer could be plugged
An increase of air leakage from ductwork
Bad compressor valve
An acid-core suction line drier

15. 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 defective circuit breaker
Condenser fans operating during a low ambient condition and a low suction pressure
('Y' and 'C') and ('G' and 'C')
Low voltage and a faulty start relay

16. What is the purpose of the TXV...
Technician B
It keeps a constant superheat in the evaporator
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
It would cause the low-side pressure to decrease

17. A rooftop package system keeps tripping out on the high-pressure switch. What are three possible causes for this problem...
Technician A
Dirty condenser - bent condenser fins - and air recirculating over the condenser
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
A blown fuse

18. When an air conditioning system has an undercharge - what happens to the superheat and the subcooling of the system...
The oil pump pressure and the crankcase pressure
A low refrigerant charge
The superheat increases and the subcooling decreases
High superheat and low discharge pressure

19. 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
Low discharge pressure - high suction pressure - and low amp draw
A defective circuit breaker
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

20. On an are-22 air conditioning system - the suction-line filter drier should be changed when the pressure drop dictates...
A defective circuit breaker
3 psig
The external equalizer could be plugged
A blown fuse

21. A rooftop package system keeps tripping out on the high-pressure switch. What are three possible causes for this problem...
Lack of airflow
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Flooding the condenser - cycling condenser fans - and dampering condenser air

22. What is the purpose of a CPR valve...
An uninsulated TXV sensing bulb
110-120
It is used to control refrigerant pressure in the compressor crankcase
The external equalizer could be plugged

23. A system that uses a thermal electric expansion valve...
A bad thermostat
The oil pump pressure and the crankcase pressure
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system

24. 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
Both technicians are incorrect
The external equalizer could be plugged
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

25. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
High suction pressure and low superheat
'G' to 'C'
A sensing bulb improperly connected to the suction line
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

26. What problem or problems can cause the discharge pressure to be low and the suction pressure to be high...
Bad compressor valve
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Low discharge pressure - high suction pressure - and low amp draw
20 to 30

27. What is a possible cause of a sweat or frost pattern downstream from a sight glass and filter dryer...
Both technicians are incorrect
A plugged filter drier
('Y' and 'C') and ('G' and 'C')
Low discharge pressure - high suction pressure - and low amp draw

28. What are two common symptoms of refrigerant leaks in an air conditioning system...
Partially frosted evaporator and high superheat
Technician B
Technician A
High suction pressure and low superheat

29. A system that is operating with a clear sight glass shows...
Technician B
Rise more than normal
The sight glass is full of liquid+the sight glass is full of gas
Partially frosted evaporator and high superheat

30. 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
High superheat and low discharge pressure
Clean the condenser coil
Current in the compressor circuit
A defective circuit breaker

31. 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 dirty condenser - recirculation of condenser air - and a defective condenser fan
Condenser fans operating during a low ambient condition and a low suction pressure
Rise more than normal
Both technicians are correct

32. When using a vapor-charged TXV bulb - it is necessary to have...
Technician A
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
A low refrigerant charge
The sensing bulb at a lower temperature than the valve body

33. 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
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
An uninsulated suction line and a restricted metering device
A start capacitor and a solid-state relay

34. 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

35. 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
Short cycling and insufficient dehumidification
Both technicians are incorrect
The external equalizer could be plugged
A low refrigerant charge

36. 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
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
Technician B
Always have some liquid present in the bulb and diaphragm
50-65

37. Which of the following will cause excessive discharge pressures on an air conditioning system...
Run with high head and high suction pressure
Technician B
An increase in low-side pressure
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system

38. What is a common discharge temperature of an air-cooled air conditioning system that is used on a 90
The superheat increases and the subcooling decreases
'G' to 'C'
110-120
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system

39. When using a vapor-charged TXV bulb - it is necessary to have...
The sensing bulb at a lower temperature than the valve body
3 psig
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

40. What are two common problems that can cause a sight glass in an air conditioning to have bubbles...
Contains a solenoid coil and one or more sets of contacts
An undercharge and low ambient conditions
Technician B
110-120

41. Which of the following will cause excessive discharge pressures on an air conditioning system...
3 psig
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down 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

42. Which of the following is a common cause of an excessively low superheat on a TXV system...
A sensing bulb improperly connected to the suction line
Technician B
Both technicians are correct
An undercharge and low ambient conditions

43. 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...
The low-side pressure will decrease and the evaporator coil will be partially frosted
Partially frosted evaporator and high superheat
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
A blown fuse

44. What are two common symptoms of refrigerant leaks in an air conditioning system...
Partially frosted evaporator and high superheat
An undercharged system+insufficient airflow over the evaporator coil
High superheat and low discharge pressure
An overcharged system

45. 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
The superheat increases and the subcooling decreases
Technician B
Condenser fans operating during a low ambient condition and a low suction pressure
An undercharge and low ambient conditions

46. A hard-start kit consists of...
Evaporator and compressor
A start relay
The internal overload is opened
A start capacitor and a solid-state relay

47. 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
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
Broken rings+broken valves+seized bearings

48. 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
Both technicians are correct
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Both technicians are incorrect
A missing air filter+improper rotation of the indoor blower+blower too small

49. 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
Both technicians are incorrect
Both technicians are incorrect
Condenser fans operating during a low ambient condition and a low suction pressure

50. What are the symptoms of a TXV air conditioning system if it has lost its charge...
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
It keeps a constant superheat in the evaporator
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
The superheat will increase and the low-side pressure will decrease