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. 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...
A start capacitor and a solid-state relay
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
The internal overload is opened

2. What is the common cause of a compressor burnout...
An overcharged system
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
A sensing bulb improperly connected to the suction line
A blown fuse

3. Superheat is found in an air conditioning system in the...
Evaporator and compressor
A dirty condenser - recirculation of condenser air - and a defective condenser fan
An increase in suction pressure and an increase in discharge pressure
Low voltage and a faulty start relay

4. What is the purpose of a CPR valve...
Technician A is correct
It is used to control refrigerant pressure in the compressor crankcase
20 to 30
High superheat and low discharge pressure

5. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
A missing air filter+improper rotation of the indoor blower+blower too small
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Technician B

6. 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
The superheat will increase and the low-side pressure will decrease

7. What are two common symptoms of an overcharged air conditioning system that uses a capillary-tube-type metering device...
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
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 would cause the low-side pressure to decrease

8. What controls are used on air conditioning or refrigeration systems that incorporate an automatic pump-down system...
Technician B
Low voltage and a faulty start relay
Low superheat
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor

9. 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...
Current in the compressor circuit
Lack of airflow
Low voltage and a faulty start relay
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

10. 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
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
20 to 30
Whenever necessary

11. What are possible problems that can cause the discharge-line temperature on an air conditioning system to be cool to the touch...
'G' to 'C'
Technician A
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
High suction pressure and low superheat

12. A restricted air filter in an air conditioning system can be identified by...
The system has been overcharged+The system has air trapped in the condenser
An acid-core suction line drier
Low superheat
An undercharge and low ambient conditions

13. 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
Clean the condenser coil
An overcharged system
A plugged filter drier
An acid-core suction line drier

14. What are the symptoms of an air conditioning system that has a bad compressor discharge valve...
Flooding the condenser - cycling condenser fans - and dampering condenser air
Low discharge pressure - high suction pressure - and low amp draw
The sensing bulb at a lower temperature than the valve body
Technician B

15. When a high-efficiency split air conditioning system has a plugged metering device - what symptoms might occur...
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Contains a solenoid coil and one or more sets of contacts
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
110-120

16. Which of the following could be the cause for a system's discharge and suction pressure being low...
Both technicians are correct
The external equalizer could be plugged
A restricted metering device
Run with high head and high suction pressure

17. A restricted air filter in an air conditioning system can be identified by...
Low superheat
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
Bad compressor valve
A missing air filter+improper rotation of the indoor blower+blower too small

18. A system that uses a thermal electric expansion valve...
It would cause the low-side pressure to decrease
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
Flooding the condenser - cycling condenser fans - and dampering condenser air

19. The temperature range of the suction line from an air conditioning system should be...
Both technicians are correct
Short cycling and insufficient dehumidification
The discharge pressure increases and the amperage increases
50-65

20. 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

21. 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
Always have some liquid present in the bulb and diaphragm
Bad compressor valve
An increase in suction pressure and an increase in discharge pressure
Both technicians are incorrect

22. What is the purpose of a CPR valve...
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
It is used to control refrigerant pressure in the compressor crankcase
Flooding the condenser - cycling condenser fans - and dampering condenser air
The system has been overcharged+The system has air trapped in the condenser

23. 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
A blown fuse
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
An increase of air leakage from ductwork

24. Insufficient airflow can be caused by...
An increase of air leakage from ductwork
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Current in the compressor circuit
An overcharged system

25. 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
3 psig
Increases starting torque
Technician A
The internal overload is opened

26. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
Technician B
Current in the compressor circuit
High suction pressure and low superheat
The discharge pressure increases and the amperage increases

27. What are the operating pressures of an oil pressure safety switch...
The oil pump pressure and the crankcase pressure
Always have some liquid present in the bulb and diaphragm
Both technicians are correct
Evaporator and compressor

28. 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...
An acid-core suction line drier
High superheat and low discharge pressure
Broken rings+broken valves+seized bearings
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

29. 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
A vacuum test+oil traces around fittings+soap bubble solution
Both technicians are incorrect
Technician B
The external equalizer could be plugged

30. 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

31. Why is it unsafe to operate an air conditioning system with a low charge...
Technician A
A missing air filter+improper rotation of the indoor blower+blower too small
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device

32. Which of the following can cause excessive subcooling...
A low refrigerant charge
An overcharged system
Flooding the condenser - cycling condenser fans - and dampering condenser air
High suction pressure and low superheat

33. What problem can cause an increase of discharge pressure and an increase of suction pressure...
'G' to 'C'
Both technicians are incorrect
An open internal overload protector
An overcharged system

34. If a TXV sensing bulb had lost its charge - what effect would this have on the air conditioning system...
The external equalizer could be plugged
Dirty condenser - bent condenser fins - and air recirculating over the condenser
It would cause the low-side pressure to decrease
A dirty condenser - recirculation of condenser air - and a defective condenser fan

35. On an are-22 air conditioning system - the suction-line filter drier should be changed when the pressure drop dictates...
Technician B
Technician B
3 psig
The internal overload is opened

36. 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
An uninsulated suction line and a restricted metering device
A low refrigerant charge
Technician B
'G' to 'C'

37. What are two common symptoms of refrigerant leaks in an air conditioning system...
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Partially frosted evaporator and high superheat
A low refrigerant charge
High superheat and low discharge pressure

38. What are common methods that are used for leak-testing a system...
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Always have some liquid present in the bulb and diaphragm
Contains a solenoid coil and one or more sets of contacts
A vacuum test+oil traces around fittings+soap bubble solution

39. What problem or problems can cause low discharge and suction pressure...
An undercharged system+insufficient airflow over the evaporator coil
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Technician B
Technician A is correct

40. What are two common symptoms of an overcharged air conditioning system that uses a capillary-tube-type metering device...
A start capacitor and a solid-state relay
An increase in suction pressure and an increase in discharge pressure
Contains a solenoid coil and one or more sets of contacts
Condenser fans operating during a low ambient condition and a low suction pressure

41. What three things can prevent an air conditioning system from absorbing heat at the proper rate...
20 to 30
Evaporator and compressor
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device

42. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...
Technician B
Run with high head and high suction pressure
Low voltage and a faulty start relay
3 psig

43. When an air conditioning system has an undercharge - what happens to the superheat and the subcooling of the system...
A vacuum test+oil traces around fittings+soap bubble solution
The superheat increases and the subcooling decreases
An uninsulated TXV sensing bulb
High superheat and low discharge pressure

44. 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
Technician B
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
A start relay
The discharge pressure increases and the amperage increases

45. Which of the following is a possible cause for a compressor to overheat...
Technician B
An undercharged system+insufficient airflow over the evaporator coil
High superheat and low discharge pressure
A low refrigerant charge

46. 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...
110-120
Short cycling and insufficient dehumidification
A blown fuse
Technician A

47. What is the purpose of an EPR valve...
Technician A is correct
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
The superheat will increase and the low-side pressure will decrease
20 to 30

48. Air filters should be replaced...
20 to 30
('Y' and 'C') and ('G' and 'C')
An undercharge and low ambient conditions
Whenever necessary

49. What causes the automatic expansion valve to close...
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
An overcharged system
Technician B
An increase in low-side pressure

50. 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
An increase of air leakage from ductwork
Technician A
A plugged filter drier