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. 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
Broken rings+broken valves+seized bearings
Technician A
3 psig
Technician B

2. Which of the following could be the cause for a system's discharge and suction pressure being low...
A start capacitor and a solid-state relay
A restricted metering device
An overcharged system
Dirty condenser - bent condenser fins - and air recirculating over the condenser

3. What problem can cause an increase of discharge pressure and an increase of suction pressure...
An overcharged system
A dirty condenser - recirculation of condenser air - and a defective condenser fan
Broken rings+broken valves+seized bearings
Rise more than normal

4. What are the symptoms of a TXV air conditioning system if it has lost its charge...
An undercharge and low ambient conditions
The oil pump pressure and the crankcase pressure
High suction pressure and low superheat
The superheat will increase and the low-side pressure will decrease

5. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
Evaporator and compressor
An increase in low-side pressure
The low-side pressure will decrease and the evaporator coil will be partially frosted
High suction pressure and low superheat

6. What are the symptoms of an air conditioning system that has a low charge...
Run with high head and high suction pressure
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Flooding the condenser - cycling condenser fans - and dampering condenser air
The low-side pressure will decrease and the evaporator coil will be partially frosted

7. The best description of a relay would be...
Technician A is correct
Contains a solenoid coil and one or more sets of contacts
Technician B
The oil pump pressure and the crankcase pressure

8. 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 oil pump pressure and the crankcase pressure
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
A sensing bulb improperly connected to the suction line

9. Why is it unsafe to operate an air conditioning system with a low charge...
Increases starting torque
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system

10. The internal overload of an air conditioning compressor senses winding temperature and...
Flooding the condenser - cycling condenser fans - and dampering condenser air
The sensing bulb at a lower temperature than the valve body
The sensing bulb at a lower temperature than the valve body
Current in the compressor circuit

11. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...
High suction pressure and low superheat
20 to 30
Broken rings+broken valves+seized bearings
An increase of air leakage from ductwork

12. 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
An increase of air leakage from ductwork
Low voltage and a faulty start relay

13. 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
Low superheat
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
An open internal overload protector

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
Bad compressor valve
Both technicians are incorrect
Broken rings+broken valves+seized bearings
An open internal overload protector

15. 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
The system has been overcharged+The system has air trapped in the condenser
Technician A
3 psig
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged

16. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
Technician B
An uninsulated suction line and a restricted metering device
Technician B
A missing air filter+improper rotation of the indoor blower+blower too small

17. Air filters should be replaced...
An overcharged system
High suction pressure and low superheat
Technician A
Whenever necessary

18. 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 start relay
Rise more than normal
Rise more than normal
Technician B

19. A system that uses a thermal electric expansion valve...
The internal overload is opened
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Clean the condenser coil
An undercharged system+insufficient airflow over the evaporator coil

20. What are two common problems that can cause a sight glass in an air conditioning to have bubbles...
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
It is used to control refrigerant pressure in the compressor crankcase
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
An undercharge and low ambient conditions

21. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
High suction pressure and low superheat
An increase in suction pressure and an increase in discharge pressure
3 psig
A plugged filter drier

22. What are common methods that are used for leak-testing a system...
3 psig
A vacuum test+oil traces around fittings+soap bubble solution
A restricted metering device
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

23. 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...
The internal overload is opened
Both technicians are correct
The superheat increases and the subcooling decreases
High superheat and low discharge pressure

24. What are two common symptoms of refrigerant leaks in an air conditioning system...
Technician A
20 to 30
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
Partially frosted evaporator and high superheat

25. 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 sensing bulb improperly connected to the suction line
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system

26. What is the purpose of an EPR valve...
It is used to control refrigerant pressure in the compressor crankcase
An increase of air leakage from ductwork
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
A bad thermostat

27. A rooftop package system keeps tripping out on the high-pressure switch. What are three possible causes for this problem...
110-120
A vacuum test+oil traces around fittings+soap bubble solution
The internal overload is opened
Dirty condenser - bent condenser fins - and air recirculating over the condenser

28. 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
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Technician B
Both technicians are incorrect
Low voltage and a faulty start relay

29. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
A missing air filter+improper rotation of the indoor blower+blower too small
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
'G' to 'C'
A start capacitor and a solid-state relay

30. 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
An increase in low-side pressure
Technician B
Dirty condenser - bent condenser fins - and air recirculating over the condenser
A sensing bulb improperly connected to the suction line

31. The internal overload of an air conditioning compressor senses winding temperature and...
An uninsulated suction line and a restricted metering device
50-65
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
Current in the compressor circuit

32. What are two problems that can cause an air conditioning system to have an excessively high superheat...
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
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
An uninsulated suction line and a restricted metering device

33. The temperature range of the suction line from an air conditioning system should be...
Lack of airflow
50-65
It would cause the low-side pressure to decrease
An overcharged system

34. What is the purpose of an EPR valve...
Whenever necessary
Low voltage and a faulty start relay
A start relay
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system

35. 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

36. What is the common cause of a compressor burnout...
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
An undercharged system+insufficient airflow over the evaporator coil
Run with high head and high suction pressure
A bad thermostat

37. What controls are used on air conditioning or refrigeration systems that incorporate an automatic pump-down system...
A low refrigerant charge
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
An acid-core suction line drier
3 psig

38. 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

39. Which of the following can cause low superheat in a TXV system...
The internal overload is opened
An undercharged system+insufficient airflow over the evaporator coil
An uninsulated TXV sensing bulb
Technician B

40. Which of the following can cause excessive subcooling...
The external equalizer could be plugged
An overcharged system
A dirty condenser - recirculation of condenser air - and a defective condenser fan
Technician B

41. What are three methods for controlling a system's high-side pressure during low ambient conditions...
It would cause the low-side pressure to decrease
Technician A is correct
Flooding the condenser - cycling condenser fans - and dampering condenser air
A low refrigerant charge

42. What three things can prevent an air conditioning system from absorbing heat at the proper rate...
A vacuum test+oil traces around fittings+soap bubble solution
An increase of air leakage from ductwork
An uninsulated TXV sensing bulb
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

43. What are two common symptoms of an overcharged air conditioning system that uses a capillary-tube-type metering device...
A restricted metering device
The superheat increases and the subcooling decreases
An uninsulated TXV sensing bulb
An increase in suction pressure and an increase in discharge pressure

44. On an are-22 air conditioning system - the suction-line filter drier should be changed when the pressure drop dictates...
A vacuum test+oil traces around fittings+soap bubble solution
3 psig
The sight glass is full of liquid+the sight glass is full of gas
Technician B

45. What type of problems can be caused by an oversized air conditioning system...
Current in the compressor circuit
Short cycling and insufficient dehumidification
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay

46. 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
Technician B
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
110-120
Technician A

47. 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 defective circuit breaker
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Technician B
A bad thermostat

48. 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
An overcharged system
Both technicians are correct
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
Dirty condenser - bent condenser fins - and air recirculating over the condenser

49. 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 B
Technician A is correct
An open internal overload protector
The system has been overcharged+The system has air trapped in the condenser

50. 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...
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Condenser fans operating during a low ambient condition and a low suction pressure
50-65
An increase in suction pressure and an increase in discharge pressure