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 is the purpose of an EPR valve...
20 to 30
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Technician B
An open internal overload protector

2. 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

3. A hard-start kit consists of...
'G' to 'C'
'G' to 'C'
A start capacitor and a solid-state relay
The system has been overcharged+The system has air trapped in the condenser

4. Which of the following is a possible cause for a compressor to overheat...
A low refrigerant charge
An increase in suction pressure and an increase in discharge pressure
Low superheat
The external equalizer could be plugged

5. 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
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
A start relay
Whenever necessary

6. When using a vapor-charged TXV bulb - it is necessary to have...
Evaporator and compressor
The sensing bulb at a lower temperature than the valve body
Both technicians are incorrect
Always have some liquid present in the bulb and diaphragm

7. 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

8. A rooftop package system keeps tripping out on the high-pressure switch. What are three possible causes for this problem...
A start capacitor and a solid-state relay
Dirty condenser - bent condenser fins - and air recirculating over the condenser
A start relay
Contains a solenoid coil and one or more sets of contacts

9. A liquid-charged TXV bulb will...
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
Bad compressor valve
Always have some liquid present in the bulb and diaphragm
Partially frosted evaporator and high superheat

10. Which of the following can cause low superheat in a TXV system...
3 psig
An uninsulated TXV sensing bulb
The internal overload is opened
An acid-core suction line drier

11. Superheat is found in an air conditioning system in the...
Low superheat
Evaporator and compressor
Contains a solenoid coil and one or more sets of contacts
An undercharged system+insufficient airflow over the evaporator coil

12. An air conditioning unit has a suction line that is frosted up to the compressor. What faults could cause this to occur...
It keeps a constant superheat in the evaporator
The discharge pressure increases and the amperage increases
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
An open internal overload protector

13. What are two common symptoms of an overcharged air conditioning system that uses a capillary-tube-type metering device...
Always have some liquid present in the bulb and diaphragm
The external equalizer could be plugged
An increase in suction pressure and an increase in discharge pressure
The system has been overcharged+The system has air trapped in the condenser

14. 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
Technician B
A blown fuse
Technician A

15. A compressor having tight bearings would cause the current value to...
An increase in suction pressure and an increase in discharge pressure
Low superheat
Rise more than normal
Technician B

16. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
Technician B
20 to 30
A bad thermostat

17. 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...
Technician B
Rise more than normal
3 psig
Low voltage and a faulty start relay

18. 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
Bad compressor valve
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Both technicians are correct
Evaporator and compressor

19. 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...
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Rise more than normal
The discharge pressure increases and the amperage increases
High superheat and low discharge pressure

20. What causes the automatic expansion valve to close...
Bad compressor valve
A low refrigerant charge
An increase in low-side pressure
The sight glass is full of liquid+the sight glass is full of gas

21. The temperature range of the suction line from an air conditioning system should be...
Technician B
A defective circuit breaker
50-65
Technician B

22. The internal overload of an air conditioning compressor senses winding temperature and...
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
Technician A is correct
The oil pump pressure and the crankcase pressure
Current in the compressor circuit

23. What is a common discharge temperature of an air-cooled air conditioning system that is used on a 90
Low superheat
An increase of air leakage from ductwork
110-120
Clean the condenser coil

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
Both technicians are incorrect
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Always have some liquid present in the bulb and diaphragm
Rise more than normal

25. 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
Flooding the condenser - cycling condenser fans - and dampering condenser air
Partially frosted evaporator and high superheat
Technician A is correct
An overcharged system

26. 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
Low discharge pressure - high suction pressure - and low amp draw
Technician B
The superheat increases and the subcooling decreases
20 to 30

27. What are two common symptoms of refrigerant leaks in an air conditioning system...
It keeps a constant superheat in the evaporator
Technician B
'G' to 'C'
Partially frosted evaporator and high superheat

28. 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...
Run with high head and high suction pressure
Low discharge pressure - high suction pressure - and low amp draw
A blown fuse
Technician A

29. A commercial customer calls on a 90
The system has been overcharged+The system has air trapped in the condenser
An uninsulated suction line and a restricted metering device
Technician B
Whenever necessary

30. A system that uses a thermal electric expansion valve...
A dirty condenser - recirculation of condenser air - and a defective condenser fan
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Technician A

31. What are three methods for controlling a system's high-side pressure during low ambient conditions...
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
It keeps a constant superheat in the evaporator
An overcharged system
Flooding the condenser - cycling condenser fans - and dampering condenser air

32. 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
Technician B
A start relay
The sensing bulb at a lower temperature than the valve body
Short cycling and insufficient dehumidification

33. When an air conditioning system has an undercharge - what happens to the superheat and the subcooling of the system...
An increase in suction pressure and an increase in discharge pressure
The superheat increases and the subcooling decreases
The sight glass is full of liquid+the sight glass is full of gas
The superheat will increase and the low-side pressure will decrease

34. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
110-120
The discharge pressure increases and the amperage increases
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
An increase in suction pressure and an increase in discharge pressure

35. 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
The discharge pressure increases and the amperage increases
Broken rings+broken valves+seized bearings
A low refrigerant charge
A vacuum test+oil traces around fittings+soap bubble solution

36. What is the purpose of a CPR valve...
A low refrigerant charge
It is used to control refrigerant pressure in the compressor crankcase
Both technicians are incorrect
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication

37. 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
Broken rings+broken valves+seized bearings
The sensing bulb at a lower temperature than the valve body
Whenever necessary
Lack of airflow

38. What is a common discharge temperature of an air-cooled air conditioning system that is used on a 90
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
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
110-120

39. Air filters should be replaced...
Whenever necessary
Run with high head and high suction pressure
Technician B
20 to 30

40. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
High suction pressure and low superheat
Low discharge pressure - high suction pressure - and low amp draw
Flooding the condenser - cycling condenser fans - and dampering condenser air
Current in the compressor circuit

41. 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
A start relay
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
A vacuum test+oil traces around fittings+soap bubble solution
Technician A

42. A customer calls with an insufficient cooling complaint on a 90
A dirty condenser - recirculation of condenser air - and a defective condenser fan
('Y' and 'C') and ('G' and 'C')
Technician B
A missing air filter+improper rotation of the indoor blower+blower too small

43. 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
A defective circuit breaker
Technician B
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Short cycling and insufficient dehumidification

44. A customer calls with an insufficient cooling complaint on a 90
Technician B
It is used to control refrigerant pressure in the compressor crankcase
Condenser fans operating during a low ambient condition and a low suction pressure
Low discharge pressure - high suction pressure - and low amp draw

45. What are two common symptoms of an overcharged air conditioning system that uses a capillary-tube-type metering device...
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
Technician B
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
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 start relay
The superheat increases and the subcooling decreases
The sensing bulb at a lower temperature than the valve body
A restricted metering device

47. What problem or problems can cause the discharge pressure to be low and the suction pressure to be high...
The superheat will increase and the low-side pressure will decrease
High superheat and low discharge pressure
Broken rings+broken valves+seized bearings
Bad compressor valve

48. 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
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
Clean the condenser coil
A defective circuit breaker

49. 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
A dirty condenser - recirculation of condenser air - and a defective condenser fan
Both technicians are incorrect
Technician B

50. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
Bad compressor valve
High suction pressure and low superheat
An undercharged system+insufficient airflow over the evaporator coil
Current in the compressor circuit