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 the symptoms of an air conditioning system that has a bad compressor discharge valve...
Rise more than normal
A low refrigerant charge
High superheat and low discharge pressure
Low discharge pressure - high suction pressure - and low amp draw

2. 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
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Technician A
The low-side pressure will decrease and the evaporator coil will be partially frosted
A blown fuse

3. 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...
Technician B
High superheat and low discharge pressure
Technician B
The sensing bulb at a lower temperature than the valve body

4. What three things can prevent an air conditioning system from releasing heat at the proper rate...
Flooding the condenser - cycling condenser fans - and dampering condenser air
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
A dirty condenser - recirculation of condenser air - and a defective condenser fan
Both technicians are incorrect

5. 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...
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Technician A
The internal overload is opened
A sensing bulb improperly connected to the suction line

6. If a TXV sensing bulb had lost its charge - what effect would this have on the air conditioning system...
It is used to control refrigerant pressure in the compressor crankcase
It would cause the low-side pressure to decrease
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
Technician B

7. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...
It is used to control refrigerant pressure in the compressor crankcase
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Run with high head and high suction pressure
An undercharged system+insufficient airflow over the evaporator coil

8. What are two common symptoms of refrigerant leaks in an air conditioning system...
Partially frosted evaporator and high superheat
Low discharge pressure - high suction pressure - and low amp draw
Whenever necessary
Dirty condenser - bent condenser fins - and air recirculating over the condenser

9. What are the symptoms of an air conditioning system that has a low charge...
Always have some liquid present in the bulb and diaphragm
High superheat and low discharge pressure
The low-side pressure will decrease and the evaporator coil will be partially frosted
Contains a solenoid coil and one or more sets of contacts

10. The internal overload of an air conditioning compressor senses winding temperature and...
An overcharged system
Current in the compressor circuit
A missing air filter+improper rotation of the indoor blower+blower too small
Low discharge pressure - high suction pressure - and low amp draw

11. What problem or problems can cause the discharge pressure to be low and the suction pressure to be high...
Bad compressor valve
The superheat will increase and the low-side pressure will decrease
The sensing bulb at a lower temperature than the valve body
Technician B

12. 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
The low-side pressure will decrease and the evaporator coil will be partially frosted
Technician B
An uninsulated TXV sensing bulb

13. What controls are used on air conditioning or refrigeration systems that incorporate an automatic pump-down system...
Low discharge pressure - high suction pressure - and low amp draw
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
Technician A is correct
A defective circuit breaker

14. 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
A plugged filter drier
20 to 30
Broken rings+broken valves+seized bearings
A vacuum test+oil traces around fittings+soap bubble solution

15. 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 sensing bulb at a lower temperature than the valve body
It would cause the low-side pressure to decrease
Technician B
Short cycling and insufficient dehumidification

16. 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 start relay
Contains a solenoid coil and one or more sets of contacts
The internal overload is opened
Both technicians are incorrect

17. What is a possible cause of a sweat or frost pattern downstream from a sight glass and filter dryer...
'G' to 'C'
A plugged filter drier
The low-side pressure will decrease and the evaporator coil will be partially frosted
High suction pressure and low superheat

18. 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
An increase in low-side pressure
'G' to 'C'
A blown fuse
Technician B

19. 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

20. When a high-efficiency split air conditioning system has a plugged metering device - what symptoms might occur...
An increase of air leakage from ductwork
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
A plugged filter drier

21. 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 B
Technician A
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
An overcharged system

22. A rooftop package system keeps tripping out on the high-pressure switch. What are three possible causes for this problem...
A restricted metering device
Dirty condenser - bent condenser fins - and air recirculating over the condenser
A sensing bulb improperly connected to the suction line
Broken rings+broken valves+seized bearings

23. Which of the following can cause low superheat in a TXV system...
An uninsulated TXV sensing bulb
A plugged filter drier
Technician A is correct
An increase in suction pressure and an increase in discharge pressure

24. 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
An increase in low-side pressure
The internal overload is opened
Both technicians are incorrect
20 to 30

25. 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
A bad thermostat
Technician B
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
Bad compressor valve

26. 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
An uninsulated suction line and a restricted metering device
'G' to 'C'
A missing air filter+improper rotation of the indoor blower+blower too small
Clean the condenser coil

27. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
Rise more than normal
Technician B
The discharge pressure increases and the amperage increases
An increase of air leakage from ductwork

28. A customer calls with an insufficient cooling complaint on a 90
High superheat and low discharge pressure
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
50-65
Technician B

29. What are three methods for controlling a system's high-side pressure during low ambient conditions...
Flooding the condenser - cycling condenser fans - and dampering condenser air
Low superheat
A plugged filter drier
A restricted metering device

30. 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...
Low voltage and a faulty start relay
Both technicians are correct
Increases starting torque
('Y' and 'C') and ('G' and 'C')

31. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
The discharge pressure increases and the amperage increases
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
Low discharge pressure - high suction pressure - and low amp draw
Dirty condenser - bent condenser fins - and air recirculating over the condenser

32. Which of the following can cause low superheat in a TXV system...
Increases starting torque
An uninsulated TXV sensing bulb
Low discharge pressure - high suction pressure - and low amp draw
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device

33. A liquid-charged TXV bulb will...
The oil pump pressure and the crankcase pressure
Lack of airflow
Increases starting torque
Always have some liquid present in the bulb and diaphragm

34. 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
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
The superheat will increase and the low-side pressure will decrease

35. 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 incorrect
The internal overload is opened
The low-side pressure will decrease and the evaporator coil will be partially frosted
Clean the condenser coil

36. Superheat is found in an air conditioning system in the...
Contains a solenoid coil and one or more sets of contacts
Evaporator and compressor
A defective circuit breaker
Flooding the condenser - cycling condenser fans - and dampering condenser air

37. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
Technician A
Clean the condenser coil
The low-side pressure will decrease and the evaporator coil will be partially frosted
A missing air filter+improper rotation of the indoor blower+blower too small

38. The technician observes a pressure drop of 25 degrees across an air conditioning evaporator coil at start-up. This drop would indicate...
The superheat will increase and the low-side pressure will decrease
Lack of airflow
50-65
An uninsulated suction line and a restricted metering device

39. 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
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
Technician A
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

40. A system that uses a thermal electric expansion valve...
Evaporator and compressor
An undercharged system+insufficient airflow over the evaporator coil
The oil pump pressure and the crankcase pressure
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system

41. The best description of a relay would be...
Contains a solenoid coil and one or more sets of contacts
Short cycling and insufficient dehumidification
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
A low refrigerant charge

42. An air conditioning unit has a suction line that is frosted up to the compressor. What faults could cause this to occur...
A low refrigerant charge
The system has been overcharged+The system has air trapped in the condenser
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Low voltage and a faulty start relay

43. A hard-start kit consists of...
The internal overload is opened
A start capacitor and a solid-state relay
An undercharge and low ambient conditions
High superheat and low discharge pressure

44. What are possible problems that can cause the discharge-line temperature on an air conditioning system to be cool to the touch...
Dirty condenser - bent condenser fins - and air recirculating over the condenser
A blown fuse
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
20 to 30

45. 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...
Both technicians are incorrect
Condenser fans operating during a low ambient condition and a low suction pressure
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
Run with high head and high suction pressure

46. What are two problems that can cause an air conditioning system to have an excessively high superheat...
An uninsulated suction line and a restricted metering device
The sight glass is full of liquid+the sight glass is full of gas
The discharge pressure increases and the amperage increases
110-120

47. Superheat is found in an air conditioning system in the...
Technician B
Evaporator and compressor
A plugged filter drier
An overcharged system

48. A liquid-charged TXV bulb will...
An undercharged system+insufficient airflow over the evaporator coil
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Always have some liquid present in the bulb and diaphragm
Broken rings+broken valves+seized bearings

49. 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
A sensing bulb improperly connected to the suction line
Technician A
Technician B
It keeps a constant superheat in the evaporator

50. 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
A restricted metering device
An uninsulated suction line and a restricted metering device
A restricted metering device