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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. Which of the following could be the cause for a system's discharge and suction pressure being low...
An increase in low-side pressure
The superheat will increase and the low-side pressure will decrease
A start relay
A restricted metering device

2. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...
Low voltage and a faulty start relay
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Run with high head and high suction pressure
Evaporator and compressor

3. Which of the following will cause excessive discharge pressures on an air conditioning system...
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
'G' to 'C'
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
110-120

4. 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
An uninsulated TXV sensing bulb
Clean the condenser coil
An uninsulated suction line and a restricted metering device
An overcharged system

5. When a high-efficiency split air conditioning system has a plugged metering device - what symptoms might occur...
Both technicians are incorrect
Low discharge pressure - high suction pressure - and low amp draw
An increase in low-side pressure
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

6. 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
An uninsulated suction line and a restricted metering device
Evaporator and compressor
Broken rings+broken valves+seized bearings
Both technicians are correct

7. A customer calls with an insufficient cooling complaint on a 90
It keeps a constant superheat in the evaporator
An acid-core suction line drier
Technician B
Low voltage and a faulty start relay

8. Why is it unsafe to operate an air conditioning system with a low charge...
Condenser fans operating during a low ambient condition and a low suction pressure
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
Low discharge pressure - high suction pressure - and low amp draw
Current in the compressor circuit

9. What are two common symptoms of refrigerant leaks in an air conditioning system...
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Short cycling and insufficient dehumidification
Partially frosted evaporator and high superheat
Broken rings+broken valves+seized bearings

10. The internal overload of an air conditioning compressor senses winding temperature and...
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
A start capacitor and a solid-state relay
Current in the compressor circuit
Always have some liquid present in the bulb and diaphragm

11. The best description of a relay would be...
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Contains a solenoid coil and one or more sets of contacts
Current in the compressor circuit
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device

12. The temperature range of the suction line from an air conditioning system should be...
It keeps a constant superheat in the evaporator
Condenser fans operating during a low ambient condition and a low suction pressure
50-65
A bad thermostat

13. What type of problems can be caused by an oversized air conditioning system...
Technician B
High superheat and low discharge pressure
Short cycling and insufficient dehumidification
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser

14. Which of the following can cause excessive subcooling...
An increase in suction pressure and an increase in discharge pressure
Flooding the condenser - cycling condenser fans - and dampering condenser air
Low discharge pressure - high suction pressure - and low amp draw
An overcharged system

15. A system that is operating with a clear sight glass shows...
The sight glass is full of liquid+the sight glass is full of gas
An increase in low-side pressure
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
A restricted metering device

16. 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
Both technicians are correct
Both technicians are incorrect
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

17. 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
A bad thermostat
An increase in suction pressure and an increase in discharge pressure
An overcharged system

18. 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
A start relay
Low discharge pressure - high suction pressure - and low amp draw
Broken rings+broken valves+seized bearings

19. A hard-start kit consists of...
A start capacitor and a solid-state relay
Partially frosted evaporator and high superheat
Broken rings+broken valves+seized bearings
It keeps a constant superheat in the evaporator

20. The temperature range of the suction line from an air conditioning system should be...
Condenser fans operating during a low ambient condition and a low suction pressure
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

21. The technician observes a pressure drop of 25 degrees across an air conditioning evaporator coil at start-up. This drop would indicate...
A blown fuse
Low superheat
Technician B
Lack of airflow

22. 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...
'G' to 'C'
The oil pump pressure and the crankcase pressure
Flooding the condenser - cycling condenser fans - and dampering condenser air
The internal overload is opened

23. What is a possible cause of a sweat or frost pattern downstream from a sight glass and filter dryer...
Dirty condenser - bent condenser fins - and air recirculating over the condenser
A plugged filter drier
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Condenser fans operating during a low ambient condition and a low suction pressure

24. When a high-efficiency split air conditioning system has a plugged metering device - what symptoms might occur...
Run with high head and high suction pressure
The external equalizer could be plugged
Technician A is correct
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure

25. A rooftop package system keeps tripping out on the high-pressure switch. What are three possible causes for this problem...
Always have some liquid present in the bulb and diaphragm
Dirty condenser - bent condenser fins - and air recirculating over the condenser
A sensing bulb improperly connected to the suction line
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

26. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.
An increase in low-side pressure
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
The discharge pressure increases and the amperage increases
Low voltage and a faulty start relay

27. 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
An increase in low-side pressure
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

28. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
'G' to 'C'
High suction pressure and low superheat
The superheat will increase and the low-side pressure will decrease
Technician A

29. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Low superheat
Low discharge pressure - high suction pressure - and low amp draw
20 to 30

30. Superheat is found in an air conditioning system in the...
Evaporator and compressor
The sensing bulb at a lower temperature than the valve body
Always have some liquid present in the bulb and diaphragm
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system

31. 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
Current in the compressor circuit
An overcharged system
Bad compressor valve

32. What are the symptoms of a TXV air conditioning system if it has lost its charge...
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
'G' to 'C'
The superheat will increase and the low-side pressure will decrease

33. 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
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Technician B
An increase in suction pressure and an increase in discharge pressure

34. 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
Short cycling and insufficient dehumidification
A blown fuse
Partially frosted evaporator and high superheat

35. What are common methods that are used for leak-testing a system...
It keeps a constant superheat in the evaporator
A restricted metering device
An increase of air leakage from ductwork
A vacuum test+oil traces around fittings+soap bubble solution

36. 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 oil pump pressure and the crankcase pressure
Technician A is correct
Rise more than normal

37. A rooftop package system keeps tripping out on the high-pressure switch. What are three possible causes for this problem...
Rise more than normal
Current in the compressor circuit
Dirty condenser - bent condenser fins - and air recirculating over the condenser
Technician A is correct

38. 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...
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Technician B
The internal overload is opened
Partially frosted evaporator and high superheat

39. What are possible problems that can cause the discharge-line temperature on an air conditioning system to be cool to the touch...
An overcharged system
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay

40. 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 bad thermostat
The external equalizer could be plugged
Run with high head and high suction pressure
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

41. What three things can prevent an air conditioning system from absorbing heat at the proper rate...
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Rise more than normal
High suction pressure and low superheat
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil

42. A restricted air filter in an air conditioning system can be identified by...
Condenser fans operating during a low ambient condition and a low suction pressure
Low superheat
It is used to control refrigerant pressure in the compressor crankcase
20 to 30

43. A customer calls and complains that his air conditioning system is not operating properly. It is noticed that the compressor is not operating. A check on the run capacitor shows that there is 33 uf and the rating on the capacitor is 40 uf. Technician
Low superheat
Increases starting torque
Technician B
Broken rings+broken valves+seized bearings

44. What are three methods for controlling a system's high-side pressure during low ambient conditions...
Current in the compressor circuit
Both technicians are incorrect
Flooding the condenser - cycling condenser fans - and dampering condenser air
An increase of air leakage from ductwork

45. What is the purpose of a CPR valve...
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Technician A
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
It is used to control refrigerant pressure in the compressor crankcase

46. A commercial customer calls on a 90
Technician B
The system has been overcharged+The system has air trapped in the condenser
The superheat will increase and the low-side pressure will decrease
Technician B

47. What are the symptoms of an air conditioning system that has a low charge...
A low refrigerant charge
Increases starting torque
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
The low-side pressure will decrease and the evaporator coil will be partially frosted

48. What problem or problems can cause the discharge pressure to be low and the suction pressure to be high...
It keeps a constant superheat in the evaporator
50-65
The system has been overcharged+The system has air trapped in the condenser
Bad compressor valve

49. What is the purpose of the TXV...
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
Short cycling and insufficient dehumidification
It keeps a constant superheat in the evaporator
A vacuum test+oil traces around fittings+soap bubble solution

50. When an air conditioning system has an undercharge - what happens to the superheat and the subcooling of the system...
The discharge pressure increases and the amperage increases
High suction pressure and low superheat
The superheat increases and the subcooling decreases
The system has been overcharged+The system has air trapped in the condenser