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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 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
It keeps a constant superheat in the evaporator
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Low voltage and a faulty start relay

2. 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 open internal overload protector
20 to 30
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
A bad thermostat

3. 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
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
A bad thermostat

4. What causes the automatic expansion valve to close...
A start capacitor and a solid-state relay
The sight glass is full of liquid+the sight glass is full of gas
A blown fuse
An increase in low-side pressure

5. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
The superheat will increase and the low-side pressure will decrease
High suction pressure and low superheat
An undercharge and low ambient conditions
A blown fuse

6. On an are-22 air conditioning system - the suction-line filter drier should be changed when the pressure drop dictates...
High suction pressure and low superheat
A low refrigerant charge
3 psig
Low superheat

7. What component is most often the cause of a start capacitor failure...
50-65
A restricted metering device
A start relay
A dirty condenser - recirculation of condenser air - and a defective condenser fan

8. 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 dirty condenser - recirculation of condenser air - and a defective condenser fan
A defective circuit breaker
An open internal overload protector
A plugged filter drier

9. 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
A bad thermostat
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
The external equalizer could be plugged

10. 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

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11. 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...
Technician B
A blown fuse
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged

12. A customer calls with an insufficient cooling complaint on a 90
('Y' and 'C') and ('G' and 'C')
A restricted metering device
A missing air filter+improper rotation of the indoor blower+blower too small
Technician B

13. Which of the following can cause excessive subcooling...
High suction pressure and low superheat
An overcharged system
Increases starting torque
Condenser fans operating during a low ambient condition and a low suction pressure

14. What is the purpose of a CPR valve...
An acid-core suction line drier
Whenever necessary
It is used to control refrigerant pressure in the compressor crankcase
An uninsulated TXV sensing bulb

15. 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 increase in suction pressure and an increase in discharge pressure
Both technicians are correct
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Technician B

16. What is the purpose of an EPR valve...
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Low discharge pressure - high suction pressure - and low amp draw

17. Insufficient airflow can be caused by...
A dirty condenser - recirculation of condenser air - and a defective condenser fan
An increase of air leakage from ductwork
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

18. A compressor having tight bearings would cause the current value to...
An undercharge and low ambient conditions
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
Rise more than normal
Broken rings+broken valves+seized bearings

19. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
An uninsulated TXV sensing bulb
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
The discharge pressure increases and the amperage increases
50-65

20. What three things can prevent an air conditioning system from releasing heat at the proper rate...
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
Clean the condenser coil
A dirty condenser - recirculation of condenser air - and a defective condenser fan
The superheat will increase and the low-side pressure will decrease

21. 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
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
An overcharged system
A missing air filter+improper rotation of the indoor blower+blower too small

22. A liquid-charged TXV bulb will...
Technician A is correct
Always have some liquid present in the bulb and diaphragm
A vacuum test+oil traces around fittings+soap bubble solution
The system has been overcharged+The system has air trapped in the condenser

23. 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
It is used to control refrigerant pressure in the compressor crankcase
Clean the condenser coil
A start relay
An undercharge and low ambient conditions

24. 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...
Low voltage and a faulty start relay
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Dirty condenser - bent condenser fins - and air recirculating over the condenser
A restricted metering device

25. What are the symptoms of a TXV air conditioning system if it has lost its charge...
The superheat will increase and the low-side pressure will decrease
An uninsulated suction line and a restricted metering device
A start capacitor and a solid-state relay
An undercharge and low ambient conditions

26. What are three methods for controlling a system's high-side pressure during low ambient conditions...
Flooding the condenser - cycling condenser fans - and dampering condenser air
Technician B
High superheat and low discharge pressure
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

27. 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
The internal overload is opened
A defective circuit breaker
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
Technician B

28. Which of the following could be the cause for a system's discharge and suction pressure being low...
An overcharged system
110-120
Technician B
A restricted metering device

29. What are possible problems that can cause the discharge-line temperature on an air conditioning system to be cool to the touch...
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
A blown fuse
Run with high head and high suction pressure
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device

30. 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
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
110-120
Evaporator and compressor
A blown fuse

31. A commercial customer calls on a 90
Rise more than normal
An undercharge and low ambient conditions
The system has been overcharged+The system has air trapped in the condenser
A defective circuit breaker

32. 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
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Bad compressor valve
Both technicians are incorrect
Technician B

33. The best description of a relay would be...
Contains a solenoid coil and one or more sets of contacts
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
It would cause the low-side pressure to decrease

34. 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
An increase in suction pressure and an increase in discharge pressure
Technician B
20 to 30
50-65

35. What is the purpose of an EPR valve...
High suction pressure and low superheat
Both technicians are incorrect
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Technician B

36. The technician observes a pressure drop of 25 degrees across an air conditioning evaporator coil at start-up. This drop would indicate...
An overcharged system
Low superheat
An increase in low-side pressure
Lack of airflow

37. A hard-start kit consists of...
Both technicians are incorrect
An undercharged system+insufficient airflow over the evaporator coil
A start capacitor and a solid-state relay
The internal overload is opened

38. What are two problems that can cause an air conditioning system to have an excessively high superheat...
An uninsulated suction line and a restricted metering device
Partially frosted evaporator and high superheat
Low discharge pressure - high suction pressure - and low amp draw
Technician B

39. A hard-start kit for an air conditioning system...
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
A plugged filter drier
It is used to control refrigerant pressure in the compressor crankcase
Increases starting torque

40. What is a common discharge temperature of an air-cooled air conditioning system that is used on a 90
110-120
50-65
An increase of air leakage from ductwork
An uninsulated TXV sensing bulb

41. What type of problems can be caused by an oversized air conditioning system...
Whenever necessary
'G' to 'C'
Contains a solenoid coil and one or more sets of contacts
Short cycling and insufficient dehumidification

42. Which of the following can cause low superheat in a TXV system...
An uninsulated TXV sensing bulb
Whenever necessary
A sensing bulb improperly connected to the suction line
Low superheat

43. What is a common discharge temperature of an air-cooled air conditioning system that is used on a 90
110-120
Clean the condenser coil
'G' to 'C'
Low superheat

44. Why is it unsafe to operate an air conditioning system with a low charge...
20 to 30
Technician A is correct
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system

45. A compressor having tight bearings would cause the current value to...
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system
Rise more than normal
High suction pressure and low superheat
An overcharged system

46. What three things can prevent an air conditioning system from absorbing heat at the proper rate...
An increase in low-side pressure
The internal overload is opened
Low voltage and a faulty start relay
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

47. What three things can prevent an air conditioning system from absorbing heat at the proper rate...
Both technicians are incorrect
Run with high head and high suction pressure
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
A sensing bulb improperly connected to the suction line

48. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...
Run with high head and high suction pressure
A blown fuse
Both technicians are incorrect
It is used to control refrigerant pressure in the compressor crankcase

49. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Increases starting torque
Run with high head and high suction pressure
Evaporator and compressor

50. 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
An open internal overload protector
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
Both technicians are incorrect