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 operating pressures of an oil pressure safety switch...
An uninsulated TXV sensing bulb
The oil pump pressure and the crankcase pressure
Both technicians are incorrect
Partially frosted evaporator and high superheat

2. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...
20 to 30
It keeps a constant superheat in the evaporator
An overcharged system
A start relay

3. What are the symptoms of an air conditioning system that has a low charge...
A missing air filter+improper rotation of the indoor blower+blower too small
The internal overload is opened
The low-side pressure will decrease and the evaporator coil will be partially frosted
An undercharge and low ambient conditions

4. 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...
An uninsulated suction line and a restricted metering device
A sensing bulb improperly connected to the suction line
A low refrigerant charge
Low voltage and a faulty start relay

5. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...
Technician B
Evaporator and compressor
An overcharged system
Run with high head and high suction pressure

6. What problem or problems can cause low discharge and suction pressure...
Evaporator and compressor
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
An undercharged system+insufficient airflow over the evaporator coil
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser

7. What are the symptoms of an air conditioning system that has a bad compressor discharge valve...
An acid-core suction line drier
Increases starting torque
Contains a solenoid coil and one or more sets of contacts
Low discharge pressure - high suction pressure - and low amp draw

8. Why is it unsafe to operate an air conditioning system with a low charge...
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
Increases starting torque
A vacuum test+oil traces around fittings+soap bubble solution
Low discharge pressure - high suction pressure - and low amp draw

9. Which of the following can cause excessive subcooling...
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
An overcharged system
The oil pump pressure and the crankcase pressure
Run with high head and high suction pressure

10. Which of the following is a possible cause for a compressor to overheat...
Contains a solenoid coil and one or more sets of contacts
A blown fuse
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
A low refrigerant charge

11. If a TXV sensing bulb had lost its charge - what effect would this have on the air conditioning system...
The oil pump pressure and the crankcase pressure
3 psig
It would cause the low-side pressure to decrease
Partially frosted evaporator and high superheat

12. What are two common symptoms of refrigerant leaks in an air conditioning system...
Partially frosted evaporator and high superheat
Technician B
Run with high head and high suction pressure
The discharge pressure increases and the amperage increases

13. A system that uses a thermal electric expansion valve...
A bad thermostat
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
The sensing bulb at a lower temperature than the valve body

14. 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
Technician B
A missing air filter+improper rotation of the indoor blower+blower too small
Low superheat

15. A hard-start kit for an air conditioning system...
Rise more than normal
Increases starting torque
An overcharged system
Technician B

16. A system that is operating with a clear sight glass shows...
Technician B
The sight glass is full of liquid+the sight glass is full of gas
It keeps a constant superheat in the evaporator
Lack of airflow

17. What are two common symptoms of refrigerant leaks in an air conditioning system...
It is used to control refrigerant pressure in the compressor crankcase
Partially frosted evaporator and high superheat
High superheat and low discharge pressure
Run with high head and high suction pressure

18. When using a vapor-charged TXV bulb - it is necessary to have...
Clean the condenser coil
The sensing bulb at a lower temperature than the valve body
Always have some liquid present in the bulb and diaphragm
3 psig

19. 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...
Current in the compressor circuit
Condenser fans operating during a low ambient condition and a low suction pressure
Clean the condenser coil
Always have some liquid present in the bulb and diaphragm

20. The internal overload of an air conditioning compressor senses winding temperature and...
Current in the compressor circuit
Technician B
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
The oil pump pressure and the crankcase pressure

21. 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
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
The internal overload is opened
Low voltage and a faulty start relay
Technician B

22. 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
Both technicians are incorrect
Technician B
Short cycling and insufficient dehumidification
20 to 30

23. 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
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Both technicians are correct
A sensing bulb improperly connected to the suction line
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device

24. Insufficient airflow can be caused by...
An increase of air leakage from ductwork
110-120
20 to 30
The discharge pressure increases and the amperage increases

25. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
A bad thermostat
Both technicians are correct
A missing air filter+improper rotation of the indoor blower+blower too small
The discharge pressure increases and the amperage increases

26. Superheat is found in an air conditioning system in the...
Low superheat
('Y' and 'C') and ('G' and 'C')
Evaporator and compressor
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

27. 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

28. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
Always have some liquid present in the bulb and diaphragm
The discharge pressure increases and the amperage increases
Broken rings+broken valves+seized bearings
The sensing bulb at a lower temperature than the valve body

29. After a compressor motor has been severely burnt - What accessory must be added as an aid to rid the air conditioning system of acid...
Current in the compressor circuit
An acid-core suction line drier
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
An increase of air leakage from ductwork

30. 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

31. What are the operating pressures of an oil pressure safety switch...
An undercharge and low ambient conditions
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
The oil pump pressure and the crankcase pressure
Technician B

32. 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
A sensing bulb improperly connected to the suction line
High superheat and low discharge pressure
Technician B

33. What three things can prevent an air conditioning system from releasing heat at the proper rate...
An open internal overload protector
Increases starting torque
A dirty condenser - recirculation of condenser air - and a defective condenser fan
An overcharged system

34. 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
Technician B
A defective circuit breaker
Technician A is correct
An undercharge and low ambient conditions

35. What is the purpose of an EPR valve...
Technician B
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
A missing air filter+improper rotation of the indoor blower+blower too small
An acid-core suction line drier

36. What is a common discharge temperature of an air-cooled air conditioning system that is used on a 90
The sensing bulb at a lower temperature than the valve body
110-120
Low superheat
It is used to control refrigerant pressure in the compressor crankcase

37. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...
20 to 30
High superheat and low discharge pressure
Bad compressor valve
A vacuum test+oil traces around fittings+soap bubble solution

38. 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
110-120
Technician B
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
An overcharged system

39. What controls are used on air conditioning or refrigeration systems that incorporate an automatic pump-down system...
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
An acid-core suction line drier
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay

40. Which of the following can cause excessive subcooling...
An overcharged system
It would cause the low-side pressure to decrease
An uninsulated TXV sensing bulb
110-120

41. 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
Condenser fans operating during a low ambient condition and a low suction pressure
The sensing bulb at a lower temperature than the valve body
A defective circuit breaker
An increase in low-side pressure

42. A compressor having tight bearings would cause the current value to...
Low superheat
The sensing bulb at a lower temperature than the valve body
Technician B
Rise more than normal

43. 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 uninsulated suction line and a restricted metering device
Both technicians are incorrect
'G' to 'C'
A bad thermostat

44. A hard-start kit for an air conditioning system...
Increases starting torque
An increase of air leakage from ductwork
The sight glass is full of liquid+the sight glass is full of gas
A missing air filter+improper rotation of the indoor blower+blower too small

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
Low discharge pressure - high suction pressure - and low amp draw
A blown fuse
Technician B
A dirty condenser - recirculation of condenser air - and a defective condenser fan

46. 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
The low-side pressure will decrease and the evaporator coil will be partially frosted
Clean the condenser coil

47. What are three methods for controlling a system's high-side pressure during low ambient conditions...
The superheat will increase and the low-side pressure will decrease
Contains a solenoid coil and one or more sets of contacts
Flooding the condenser - cycling condenser fans - and dampering condenser air
Technician B

48. What are two common symptoms of an overcharged air conditioning system that uses a capillary-tube-type metering device...
An increase in suction pressure and an increase in discharge pressure
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
It keeps a constant superheat in the evaporator
An overcharged system

49. Which of the following is a possible cause for a compressor to overheat...
A low refrigerant charge
Run with high head and high suction pressure
The external equalizer could be plugged
A start capacitor and a solid-state relay

50. 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
The external equalizer could be plugged
High superheat and low discharge pressure
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
'G' to 'C'