Test your basic knowledge |

NATE Air Conditioning Troubleshooting

Subjects : engineering, nate
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. An air conditioning unit has a suction line that is frosted up to the compressor. What faults could cause this to occur...






2. A compressor having tight bearings would cause the current value to...






3. On an are-22 air conditioning system - the suction-line filter drier should be changed when the pressure drop dictates...






4. What is the common cause of a compressor burnout...






5. A system that uses a thermal electric expansion valve...






6. A customer calls and complains that her high-efficiency air conditioning system is operating - but is not cooling properly. Further investigation shows that the system is using a TXV type of metering device. A subcooling check shows that the system a






7. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.






8. Why is it unsafe to operate an air conditioning system with a low charge...






9. Name two symptoms that are common to an over-charged air conditioning system and a system that has a dirty condenser.






10. 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






11. 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






12. What is a possible cause of a sweat or frost pattern downstream from a sight glass and filter dryer...






13. The temperature range of the suction line from an air conditioning system should be...






14. 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






15. What problem or problems can cause low discharge and suction pressure...






16. What is a possible cause of a sweat or frost pattern downstream from a sight glass and filter dryer...






17. When an air conditioning system has an undercharge - what happens to the superheat and the subcooling of the 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






19. 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






20. A liquid-charged TXV bulb will...






21. The internal overload of an air conditioning compressor senses winding temperature and...






22. If a TXV sensing bulb had lost its charge - what effect would this have on the air conditioning system...






23. What is the purpose of an EPR valve...






24. What types of symptoms will be present if the sensing bulb of a TXV is not properly connected...






25. 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






26. A system that uses a thermal electric expansion valve...






27. What are the symptoms of a TXV air conditioning system if it has lost its charge...






28. A hard-start kit for an air conditioning system...






29. What controls are used on air conditioning or refrigeration systems that incorporate an automatic pump-down system...






30. 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...






31. What are common methods that are used for leak-testing a system...






32. What is a common temperature difference between the condensing temperature on an air-cooled condensing unit and the outdoor ambient temperature...






33. An air conditioning unit has a suction line that is frosted up to the compressor. What faults could cause this to occur...






34. 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






35. Which of the following can cause excessive subcooling...






36. 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...






37. What causes the automatic expansion valve to close...






38. 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






39. 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






40. The best description of a relay would be...






41. Air filters should be replaced...






42. When using a vapor-charged TXV bulb - it is necessary to have...






43. 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






44. 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






45. What is a common discharge temperature of an air-cooled air conditioning system that is used on a 90






46. What are three methods for controlling a system's high-side pressure during low ambient conditions...






47. What is the purpose of a CPR valve...






48. An air conditioning system using a fixed-orifice metering device and with noncondensables in the system will cause...






49. A rooftop package system keeps tripping out on the high-pressure switch. What are three possible causes for this problem...






50. What type of problems can be caused by an oversized air conditioning system...