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A refrigerant is a substance to produce a refrigeration effect by what?

Learn about refrigerants, measurement tools, pipe sizing, welding, safety precautions, and more in HVAC systems.

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A refrigerant is a substance to produce a refrigeration effect by what?

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  1. A refrigerant is a substance to produce a refrigeration effect by what? Condensation Compression Loss of pressure Expansion or vaporization

  2. A refrigerant is a substance to produce a refrigeration effect by what? Condensation Compression Loss of pressure Expansion or vaporization

  3. What will most likely cause frost on suction line at the capillary tube? Low head Refrigerant overcharge Compressor short cycle Excessive evaporator superheat

  4. What will most likely cause frost on suction line at the capillary tube? Low head Refrigerant overcharge Compressor short cycle Excessive evaporator superheat

  5. To measure within 1/1000 of an inch a mechanic uses what? Micrometer Machinist rule Depth Gauge Psychrometer

  6. To measure within 1/1000 of an inch a mechanic uses what? Micrometer Machinist rule Depth Gauge Psychrometer

  7. What is the saturated pressure of R 22 at 140 deg. F.? 157.6 206.6 337.2 247.7

  8. What is the saturated pressure of R 22 at 140 deg. F.? 157.6 206.6 337.2 247.7

  9. Capacity of an evaporative condenser depends on entering air temperature. Dry bulb Wet bulb Dew point Differential

  10. Capacity of an evaporative condenser depends on entering air temperature. Dry bulb Wet bulb Dew point Differential

  11. What device measures manifold pressure? Pieto tube Manometers Thermometer Sail switch

  12. What device measures manifold pressure? Pieto tube Manometers Thermometer Sail switch

  13. Wheatstone bridge circuit is in balance when? Total resistance is zero Galvometer indicates a positive current Input voltage is zero Galvometer indicates zero

  14. Wheatstone bridge circuit is in balance when? Total resistance is zero Galvometer indicates a positive current Input voltage is zero Galvometer indicates zero

  15. Pneumatic control system valves/motors are considered as Relays Anticipators Operators Components

  16. Pneumatic control system valves/motors are considered as Relays Anticipators Operators Components

  17. Saturated suction line temperature of 20 deg. F, condenser temperature of 110 deg. F, R 12 Refrigerant with 2 deg. F drop, the line is 100 ft. long, and 50 tons. What is line size? 2 5/8 3 1/8 4 1/8 5 1/8

  18. Saturated suction line temperature of 20 deg. F, condenser temperature of 110 deg. F, R 12 Refrigerant with 2 deg. F drop, the line is 100 ft. long, and 50 tons. What is line size? 2 5/8 3 1/8 4 1/8 5 1/8

  19. You have a gas pipe 2 inches at .60 specific gravity with a water column drop of 0.5 inches, 486 ft long, how much gas can it carry? 484 960 5757 9391

  20. You have a gas pipe 2 inches at .60 specific gravity with a water column drop of 0.5 inches, 486 ft long, how much gas can it carry? 484 960 5757 9391 IFG 2006 Ta 402.4(2)

  21. In copper soldering, which is the best to ensure a strong leak tight joint? Removing burs Fluxing the outside of the pipe Cleaning with abrasive cloth Cleaning

  22. In copper soldering, which is the best to ensure a strong leak tight joint? Removing burs Fluxing the outside of the pipe Cleaning with abrasive cloth Cleaning

  23. What type of piping in a refrigeration line can be welded? Black iron (steel) Copper Brass Forged

  24. What type of piping in a refrigeration line can be welded? Black iron (steel) Copper Brass Forged

  25. How many turns do you open a LP cylinder gas valve and consider it safe number of turns? ¼ ½ 1 1 ½

  26. How many turns do you open a LP cylinder gas valve and consider it safe number of turns? ¼ ½ 1 1 ½

  27. Extension cords shall be hung by…….. Wire Nails Staples None of the above

  28. Extension cords shall be hung by…….. Wire Nails Staples None of the above

  29. You have .09 static, 100 ft duct run, the recommended cfm of the branch supply duct is 900 cfm, what size is this duct board branch? 16 X 16 16 X 13 13 X 13 13 X 18

  30. You have .09 static, 100 ft duct run, the recommended cfm of the branch supply duct is 900 cfm, what size is this duct board branch? 16 X 16 16 X 13 13 X 13 13 X 18 ACCA Ductulator

  31. You have an under floor furnace with an access hole thru the foundation what size must it be? 18 X 18 30 X 30 24 X 24 26 X 26

  32. You have an under floor furnace with an access hole thru the foundation what size must it be? 18 X 18 30 X 30 24 X 24 26 X 26

  33. Fuel shut off valve must be within how many feet of the equipment? 1 ½ ft 2 ft 3 ft 6 ft

  34. Fuel shut off valve must be within how many feet of the equipment? 1 ½ ft 2 ft 3 ft 6 ft

  35. Under ground ducts require how much insulation? R 5 R 11 R 4 None

  36. Under ground ducts require how much insulation? R 5 R 11 R 4 None

  37. An appliance in a confined space with all combustion air from inside the building, what is the minimum square of the opening size? 50 75 100 500

  38. An appliance in a confined space with all combustion air from inside the building, what is the minimum square of the opening size? 50 75 100 500

  39. In a refrigeration manifold gauge, what best describes them? Compound gauge has hose nearest the suction Saturated temperature is on the outer scale Discharged hose is always yellow 5-degree increments on high pressure gauge scale

  40. In a refrigeration manifold gauge, what best describes them? Compound gauge has hose nearest the suction Saturated temperature is on the outer scale Discharged hose is always yellow 5-degree increments on high pressure gauge scale

  41. You have a 10 X 10 wall with a difference in temperature of 65 deg. from one side to the other, how many BTU’s are being lost at an R 11 insulation value? 585 925 650 465

  42. You have a 10 X 10 wall with a difference in temperature of 65 deg. from one side to the other, how many BTU’s are being lost at an R 11 insulation value? 585 925 650 465

  43. In testing a start capacitor, you bleed it off by? Shorting it to ground Laying a screw driver across the terminals Place a 2-watt resistor across terminals None of the above

  44. In testing a start capacitor, you bleed it off by? Shorting it to ground Laying a screw driver across the terminals Place a 2-watt resistor across terminals None of the above ARI 2 watt 20,000 ohms

  45. Which of these is not a water-cooled condenser? Cascade Tube in tube Shell & oil Shell & tube

  46. Which of these is not a water-cooled condenser? Cascade Tube in tube Shell & oil Shell & tube

  47. What does a monometer measure? Pressure Current Voltage Wet bulb

  48. What does a monometer measure? Pressure Current Voltage Wet bulb

  49. The dry expansion type coil is designed for what? Partial evaporation of refrigeration in coil All evaporation of refrigerant in coil 80% evaporation of refrigerant in coil None of the above

  50. The dry expansion type coil is designed for what? Partial evaporation of refrigeration in coil All evaporation of refrigerant in coil 80% evaporation of refrigerant in coil None of the above

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