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. A restricted air filter in an air conditioning system can be identified by...
A vacuum test+oil traces around fittings+soap bubble solution
Clean the condenser coil
A bad thermostat
Low superheat

2. What are the operating pressures of an oil pressure safety switch...
Short cycling and insufficient dehumidification
The oil pump pressure and the crankcase pressure
Rise more than normal
Contains a solenoid coil and one or more sets of contacts

3. What is the common cause of a compressor burnout...
An undercharge and low ambient conditions
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
A dirty condenser - recirculation of condenser air - and a defective condenser fan
50-65

4. The temperature range of the suction line from an air conditioning system should be...
Run with high head and high suction pressure
A low refrigerant charge
An overcharged system
50-65

5. 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
Technician B
Dirty condenser - bent condenser fins - and air recirculating over the condenser
An undercharged system+insufficient airflow over the evaporator coil
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged

6. The best description of a relay would be...
Technician B
Contains a solenoid coil and one or more sets of contacts
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Short cycling and insufficient dehumidification

7. A system that is operating with a clear sight glass shows...
A low refrigerant charge
It is used to control refrigerant pressure in the compressor crankcase
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

8. What three things can prevent an air conditioning system from absorbing heat at the proper rate...
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
A blown fuse
The sensing bulb at a lower temperature than the valve body

9. An air conditioning unit has a suction line that is frosted up to the compressor. What faults could cause this to occur...
Short cycling and insufficient dehumidification
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
It would cause the low-side pressure to decrease

10. What is the purpose of the TXV...
A bad thermostat
Low superheat
It keeps a constant superheat in the evaporator
An undercharged system+insufficient airflow over the evaporator coil

11. A hard-start kit consists of...
An increase in suction pressure and an increase in discharge pressure
Low voltage and a faulty start relay
A dirty condenser - recirculation of condenser air - and a defective condenser fan
A start capacitor and a solid-state relay

12. What problem can cause an increase of discharge pressure and an increase of suction pressure...
An increase of air leakage from ductwork
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
The discharge pressure increases and the amperage increases
An overcharged system

13. A customer calls with an insufficient cooling complaint on a 90
A plugged filter drier
A sensing bulb improperly connected to the suction line
Partially frosted evaporator and high superheat
Technician B

14. 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
Dirty condenser - bent condenser fins - and air recirculating over the condenser
A vacuum test+oil traces around fittings+soap bubble solution
It would cause the low-side pressure to decrease
Technician B

15. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
A missing air filter+improper rotation of the indoor blower+blower too small
Technician A
Increases starting torque
The discharge pressure increases and the amperage increases

16. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
The superheat will increase and the low-side pressure will decrease
A missing air filter+improper rotation of the indoor blower+blower too small
An overcharged system
Clean the condenser coil

17. 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
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
An open internal overload protector
Both technicians are incorrect
An increase in suction pressure and an increase in discharge pressure

18. When a high-efficiency split air conditioning system has a plugged metering device - what symptoms might occur...
A sensing bulb improperly connected to the suction line
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
The low-side pressure will decrease and the evaporator coil will be partially frosted
Both technicians are correct

19. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
Technician B
The discharge pressure increases and the amperage increases
High suction pressure and low superheat
Increases starting torque

20. 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

21. 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
The superheat will increase and the low-side pressure will decrease
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
Technician B

22. 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
The low-side pressure will decrease and the evaporator coil will be partially frosted
The internal overload is opened
Technician A is correct
It is used to control refrigerant pressure in the compressor crankcase

23. Which of the following is a common cause of an excessively low superheat on a TXV system...
An undercharged system+insufficient airflow over the evaporator coil
The low-side pressure will decrease and the evaporator coil will be partially frosted
A sensing bulb improperly connected to the suction line
A missing air filter+improper rotation of the indoor blower+blower too small

24. A system that is operating with a clear sight glass shows...
An undercharged system+insufficient airflow over the evaporator coil
Contains a solenoid coil and one or more sets of contacts
Rise more than normal
The sight glass is full of liquid+the sight glass is full of gas

25. Which of the following will cause excessive discharge pressures on an air conditioning system...
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
It is used to control refrigerant pressure in the compressor crankcase
A sensing bulb improperly connected to the suction line
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system

26. When an air conditioning system has an undercharge - what happens to the superheat and the subcooling of the system...
High suction pressure and low superheat
The superheat increases and the subcooling decreases
Lack of airflow
The system has been overcharged+The system has air trapped in the condenser

27. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...
'G' to 'C'
Bad compressor valve
20 to 30
A bad thermostat

28. 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...
Technician B
A plugged filter drier
Technician B
Condenser fans operating during a low ambient condition and a low suction pressure

29. What problem or problems can cause low discharge and suction pressure...
An undercharge and low ambient conditions
Run with high head and high suction pressure
Flooding the condenser - cycling condenser fans - and dampering condenser air
An undercharged system+insufficient airflow over the evaporator coil

30. 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
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
High superheat and low discharge pressure
Evaporator and compressor

31. Superheat is found in an air conditioning system in the...
Technician B
Technician B
Evaporator and compressor
Technician B

32. A commercial customer calls on a 90
Rise more than normal
An uninsulated TXV sensing bulb
Both technicians are correct
The system has been overcharged+The system has air trapped in the condenser

33. An air conditioning unit has a suction line that is frosted up to the compressor. What faults could cause this to occur...
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
High superheat and low discharge pressure
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Contains a solenoid coil and one or more sets of contacts

34. What causes the automatic expansion valve to close...
Short cycling and insufficient dehumidification
A start relay
An acid-core suction line drier
An increase in low-side pressure

35. When a high-efficiency split air conditioning system has a plugged metering device - what symptoms might occur...
Rise more than normal
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Run with high head and high suction pressure

36. What are the symptoms of an air conditioning system that has a bad compressor discharge valve...
('Y' and 'C') and ('G' and 'C')
A start capacitor and a solid-state relay
It is used to control refrigerant pressure in the compressor crankcase
Low discharge pressure - high suction pressure - and low amp draw

37. What are two common symptoms of refrigerant leaks in an air conditioning system...
Low voltage and a faulty start relay
An overcharged system
Partially frosted evaporator and high superheat
50-65

38. What are common methods that are used for leak-testing a system...
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
A dirty condenser - recirculation of condenser air - and a defective condenser fan
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
A vacuum test+oil traces around fittings+soap bubble solution

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
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
Low voltage and a faulty start relay
Technician B
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged

40. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...
An increase in suction pressure and an increase in discharge pressure
Run with high head and high suction pressure
The superheat will increase and the low-side pressure will decrease
Dirty condenser - bent condenser fins - and air recirculating over the condenser

41. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
Clean the condenser coil
The discharge pressure increases and the amperage increases
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Technician B

42. 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
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
A start capacitor and a solid-state relay
Clean the condenser coil

43. What are two common symptoms of an overcharged air conditioning system that uses a capillary-tube-type metering device...
Dirty condenser - bent condenser fins - and air recirculating over the condenser
An increase in suction pressure and an increase in discharge pressure
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Both technicians are incorrect

44. What are the operating pressures of an oil pressure safety switch...
The oil pump pressure and the crankcase pressure
Technician A is correct
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
It keeps a constant superheat in the evaporator

45. The technician observes a pressure drop of 25 degrees across an air conditioning evaporator coil at start-up. This drop would indicate...
Contains a solenoid coil and one or more sets of contacts
Lack of airflow
A bad thermostat
An increase in suction pressure and an increase in discharge pressure

46. What component is most often the cause of a start capacitor failure...
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
Broken rings+broken valves+seized bearings
The superheat will increase and the low-side pressure will decrease
A start relay

47. What are two problems that can cause an air conditioning system to have an excessively high superheat...
An increase in suction pressure and an increase in discharge pressure
An uninsulated suction line and a restricted metering device
Technician A
A start capacitor and a solid-state relay

48. 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
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Technician B
The sensing bulb at a lower temperature than the valve body
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

49. 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...

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

50. A compressor having tight bearings would cause the current value to...
An overcharged system
A plugged filter drier
Short cycling and insufficient dehumidification
Rise more than normal