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 problem or problems can cause the discharge pressure to be low and the suction pressure to be high...
Bad compressor valve
110-120
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
An overcharged system

2. Which of the following is a possible cause for a compressor to overheat...
A low refrigerant charge
110-120
Short cycling and insufficient dehumidification
It keeps a constant superheat in the evaporator

3. Which of the following problems can cause a decrease in a system's pressures and possible icing of the evaporator coil...
Low voltage and a faulty start relay
A missing air filter+improper rotation of the indoor blower+blower too small
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

4. Why is it unsafe to operate an air conditioning system with a low charge...
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication
('Y' and 'C') and ('G' and 'C')
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Both technicians are incorrect

5. 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 undercharge and low ambient conditions
Both technicians are correct
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Whenever necessary

6. A system that uses a thermal electric expansion valve...
Condenser fans operating during a low ambient condition and a low suction pressure
Both technicians are incorrect
An uninsulated TXV sensing bulb
Can use the thermal electric expansion valve instead of a liquid-line solenoid as part of the pump-down system

7. A liquid-charged TXV bulb will...
Clean the condenser coil
A sensing bulb improperly connected to the suction line
Technician B
Always have some liquid present in the bulb and diaphragm

8. If a TXV sensing bulb had lost its charge - what effect would this have on the air conditioning system...
Clean the condenser coil
Low discharge pressure - high suction pressure - and low amp draw
A defective circuit breaker
It would cause the low-side pressure to decrease

9. What problem or problems can cause low discharge and suction pressure...
High suction pressure and low superheat
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
The low-side pressure will decrease and the evaporator coil will be partially frosted
An undercharged system+insufficient airflow over the evaporator coil

10. What three things can prevent an air conditioning system from absorbing heat at the proper rate...
A bad thermostat
A restricted metering device
A dirty evaporator coil - a defective evaporator fan - and an iced-up evaporator coil
An uninsulated suction line and a restricted metering device

11. The best description of a relay would be...
An undercharge and low ambient conditions
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
Bad compressor valve
Contains a solenoid coil and one or more sets of contacts

12. 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
Technician B
Current in the compressor circuit
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
Short cycling and insufficient dehumidification

13. A liquid-charged TXV bulb will...
Run with high head and high suction pressure
The system has been overcharged+The system has air trapped in the condenser
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
Always have some liquid present in the bulb and diaphragm

14. The temperature range of the suction line from an air conditioning system should be...
The superheat increases and the subcooling decreases
Evaporator and compressor
The superheat increases and the subcooling decreases
50-65

15. 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

16. A restricted air filter in an air conditioning system can be identified by...
Low superheat
Both technicians are incorrect
The system has been overcharged+The system has air trapped in the condenser
Technician B

17. What are the symptoms of an air conditioning system that has a low charge...
The low-side pressure will decrease and the evaporator coil will be partially frosted
A start relay
Technician B
An overcharged system

18. 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
Run with high head and high suction pressure
'G' to 'C'
Technician B
A bad thermostat

19. What type of problems can be caused by an oversized air conditioning system...
The sight glass is full of liquid+the sight glass is full of gas
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
Short cycling and insufficient dehumidification
A bad thermostat

20. What is the purpose of an EPR valve...
Both technicians are incorrect
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
Increases starting torque

21. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...
Clean the condenser coil
High suction pressure and low superheat
A low refrigerant charge
Contains a solenoid coil and one or more sets of contacts

22. 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...
A dirty condenser - recirculation of condenser air - and a defective condenser fan
High superheat and low discharge pressure
The sensing bulb at a lower temperature than the valve body
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system

23. Insufficient airflow can be caused by...
The low-side pressure will decrease and the evaporator coil will be partially frosted
Low discharge pressure - high suction pressure - and low amp draw
Technician B
An increase of air leakage from ductwork

24. A customer calls with an insufficient cooling complaint on a 90
Technician B
An increase in low-side pressure
An acid-core suction line drier
An uninsulated suction line and a restricted metering device

25. Superheat is found in an air conditioning system in the...
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
Evaporator and compressor
The superheat will increase and the low-side pressure will decrease

26. 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
The sensing bulb at a lower temperature than the valve body
Technician A is correct
A low amp draw - a decrease in high-side pressure - and a decrease in low-side pressure
An uninsulated TXV sensing bulb

27. What controls are used on air conditioning or refrigeration systems that incorporate an automatic pump-down system...
A thermostat cycles the liquid-line solenoid - and a low-pressure switch controls the compressor
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
It keeps a constant superheat in the evaporator
High suction pressure and low superheat

28. 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
Technician A is correct
Contains a solenoid coil and one or more sets of contacts
Whenever necessary
A defective circuit breaker

29. 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
Both technicians are incorrect
A blown fuse
It is used to control refrigerant pressure in the compressor crankcase

30. 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
Short cycling and insufficient dehumidification
Technician A is correct
A plugged filter drier
Run with high head and high suction pressure

31. What causes the automatic expansion valve to close...
An increase in low-side pressure
An increase in suction pressure and an increase in discharge pressure
Technician B
High superheat and low discharge pressure

32. 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
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
The sight glass is full of liquid+the sight glass is full of gas
A defective circuit breaker

33. Why is it unsafe to operate an air conditioning system with a low charge...
An overcharged system
The sensing bulb at a lower temperature than the valve body
Run with high head and high suction pressure
It can seize the compressor because of excessive heat+It can seize the compressor because of lack of lubrication

34. After a compressor motor has been severely burnt - What accessory must be added as an aid to rid the air conditioning system of acid...
A start relay
The sensing bulb at a lower temperature than the valve body
Flooding the condenser - cycling condenser fans - and dampering condenser air
An acid-core suction line drier

35. What causes the automatic expansion valve to close...
Always have some liquid present in the bulb and diaphragm
An increase in low-side pressure
Run with high head and high suction pressure
The low-side pressure will decrease and the evaporator coil will be partially frosted

36. What is a common discharge temperature of an air-cooled air conditioning system that is used on a 90
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
The sight glass is full of liquid+the sight glass is full of gas
Both technicians are incorrect
110-120

37. 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
The system could be undercharged+The compressor could have bad valves+The system could have a restricted metering device
It increases pressure in a high-temperature evaporator coil when it is used on a dual-evaporator system
The system has been overcharged+The system has air trapped in the condenser

38. 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
A start capacitor and a solid-state relay
Both technicians are incorrect
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
A plugged filter drier

39. 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...
Condenser air being recirculated over the condenser+air trapped in the condenser due to poor service procedures+an overcharged air conditioning system
Both technicians are incorrect
The superheat increases and the subcooling decreases
Condenser fans operating during a low ambient condition and a low suction pressure

40. When an air conditioning system has an undercharge - what happens to the superheat and the subcooling of the system...
Clean the condenser coil
Technician A is correct
An overcharged system
The superheat increases and the subcooling decreases

41. What problem can cause an increase of discharge pressure and an increase of suction pressure...
Improper system evacuation during installation+short cycling of the system+excessively dirty condenser
The system was improperly serviced and it has air trapped in the condenser or the unit has been overcharged
An increase in low-side pressure
An overcharged system

42. Air filters should be replaced...
An acid-core suction line drier
Whenever necessary
Low voltage and a faulty start relay
An increase of air leakage from ductwork

43. An air conditioning unit has a suction line that is frosted up to the compressor. What faults could cause this to occur...
A dirty evaporator coil+a plugged air filter+a bad indoor blower relay
Lack of airflow
The system has been overcharged+The system has air trapped in the condenser
Technician B

44. What is a possible cause of a sweat or frost pattern downstream from a sight glass and filter dryer...
'G' to 'C'
A plugged filter drier
The low-side pressure will decrease and the evaporator coil will be partially frosted
('Y' and 'C') and ('G' and 'C')

45. The best description of a relay would be...
Contains a solenoid coil and one or more sets of contacts
Current in the compressor circuit
An increase in low-side pressure
Condenser fans operating during a low ambient condition and a low suction pressure

46. 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
Whenever necessary
A bad thermostat
An overcharged system
The oil pump pressure and the crankcase pressure

47. 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...
An overcharged system
Condenser fans operating during a low ambient condition and a low suction pressure
A sensing bulb improperly connected to the suction line
3 psig

48. After a compressor motor has been severely burnt - What accessory must be added as an aid to rid the air conditioning system of acid...
Flooding the condenser - cycling condenser fans - and dampering condenser air
An acid-core suction line drier
It would cause the low-side pressure to decrease
Partially frosted evaporator and high superheat

49. What are the symptoms of a TXV air conditioning system if it has lost its charge...
Low discharge pressure - high suction pressure - and low amp draw
It would cause the low-side pressure to decrease
Lack of airflow
The superheat will increase and the low-side pressure will decrease

50. 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
A start capacitor and a solid-state relay
Technician B
The sight glass is full of liquid+the sight glass is full of gas
Bad compressor valve