HVAC Interview Questions

INTERVIEW QUESTION’S 1. What is local comfort cooling system ? 2. What is Centralised air system ? 3. What is Constant volume system ? 4. What is Variable air volume system & Dual duct system ? 5. What is Hydronic system or Air-Water system ? 6. What is ASHRAE ,SMACNA & DW-142 ? 7. How vapour compression cycle works ? 8. What is the pressure and temperature of refrigerant at expansion valve and condenser ? – 26C 1BAR IN EVAPORATOR , 60 C AND 17 BAR IN COMPRESSOR, 18 C, 4.4 BAR IN CONDESER 9. What is Refrigerant ? 10. How the cleaning process is done before the gas is filled in the piping system ? 11. How is the leak detection of refrigerant piping is done ? 12. What is Humidification & Dehumudification ? 13. What is Dry bulb temperature, Wet bulb temperature, Relative humidity, Dew point temperature ? 14.

What the horizontal lines, vertical lines, curved lines represents in Pyschometric chart? Dbt, grains of moisture(sensible heat factor), wbt

15. What is Sensible heat & Latent heat ? 16. What is tonne Refrigeration ? 17. What is Btu ? 18. What is Cfm & Infiltration ?

19. What are the types of air conditioning systems ? 20. What is the entering & leaving air temperature in AHU ? 21. What are the factors to be considered to calculate the heat gain ? 22. What is Bypass factor & Contact factor ? 23. What is fresh air, return air & supply air ? 24. In Q=AV, What is Q, A & V ? 25. How the lighting load is calculated ? 26. What is the function of AHU ? 27. Where the Fcu’s are used ? 28. What are the types of compressors ? 29. What are the types of condensers ? 30. What will be the temperature of water entering into condenser ? 31. What are the types of Piping system in hydronic system ? 32. What is heat recovery system ? 33. What are the types of fans used ? 34. What are the components of ducting system & types of duct sizing methods ? 35. What is Aspect ratio ? 36. What are the components of chilled water system ? 37. What are the types of chiller’s and their functioning ? 38. What are the types of condensers ? 39. What are types of Valves and why the yare used in piping system ? 40. What is a Heat Exchanger ? 41. What are the job responsibilities of an Hvac Engineer ?

42. What does Air changes per hour(ACH) means ? 43. What is Gpm ? 44. How the water is prevented from changing state from liquid to ice in chilled water system ? 45. Why the room thermostat is used ? 46. What is single line diagram ? 47. What is psychometry ? 48. What are the types of filters ? 49. Why high efficiency filters are used ? 50. Why the reducers are provided in the ducting system ? 51. Why Ventilation is done to a space ? 52. Where the Valves are to be installed in the piping system ? 53. What is the assumed contact factor and bypass factor ? 54. What type of compressors are used in chillers and split a/c ? 55. How the friction losses are calculated in ducting system ? 56. What type of friction is observed in the ducting system ? 57. what is enthalpy 58. how people load is calculated 59. what is infiltration load 60. what are the different valves for chilled water piping 61. how many types of chillers are there 62. what is cladding 63. what is chilled water supply temp

64. what is chilled water leaving temp 65. how many types of diffusers are there 66. how many types of AHU ‘s are there 67. what is the purpose of a volume damper 68. what is external static pressure of fan 69. what is the system design pressure for chilled water system 70. which material is used for duct construction 71. How many types of compressors are there. 72. how many types of cooling coils are there 73. How many types heating coils are there