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Residential Air Conditioning

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. How is ACR tubing sized?
8
Outside diameter (OD)
In parallel
True

2. Do you need a trap on a push-through evaporator?
200
To lower the amount of pressure drop through the coil
No
Btu/hr (output) / wattage (input)

3. At what temperature will soft solder melt?
Inside diameter (ID)
Side-by-side and over-and-under
Any amount
Below 800 degrees F

4. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
Over/under and side by side
40 A
45-55%
By increasing the surface of the condenser coil

5. 8' round duct has a ballpark cfm of what?
18 gauge
200
12000
Any amount

6. How do you calculate EER?
30 degrees F
Over/under and side by side
Btu/hr (output) / wattage (input)
A dirty evaporator

7. What component changes refrigerant from a low pressure gas to a high pressure gas?
Indoor fan motor - outdoor fan motor - and the compressor
2
Compressor
High

8. What is it called when liquid refrigerant gets into the compressor?
Positive
Slugging
In series
A dirty evaporator

9. How long should you leave a system off once you kill power before restarting it?
40 degrees F
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
2 minutes
45 degrees F

10. Why are some ACR tubing lines insulated?
False
True
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Latent and sensible

11. How are the condenser coils different on a high-efficiency unit?
Vapor
They are larger
2
To remove humidity and lower dry bulb temperature

12. What are the two types of package units?
When it is a pull-through evaporator
Side-by-side and over-and-under
A bypass duct or a dump zone
Suction

13. What tool is used to expand the diameter of soft copper tubing
It will have a decrease in superheat
A swaging tool
It will be high
45 degrees F

14. What is the typical temperature difference between a high-efficiency condenser and the ambient temperature?
20 degrees F
12000
Rise
Heat loss

15. Where do you check the amps on a motor?
When the system is under pressure
They are larger
Blended refrigerants
On the common terminal

16. How long should you leave a system off once you kill power before restarting it?
25-ft or 50-ft
Yes
2 minutes
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.

17. Superheat should never be below how many degrees
When it is above a conditioned space
5 degrees
Yes
8-12 degrees F

18. If the rpm's are 1750 - how many poles does the motor have?
2 minutes
Subtract ambient temperature from 100
4
Boil the liquid refrigerant out ot the oil within the crankcase

19. How are round ducts supported?

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20. How many cfm per ton?
400
Yes
When it is a pull-through evaporator
45 degrees F

21. The furnace size is calculated by what?
Heat loss
A diffuser
Yes
1/4'

22. Where do you apply flux when soldering?
Outside of the male fitting
When it is above a conditioned space
A diffuser
4

23. At what temperature will brazing melt?
A dirty evaporator
Over 800 degrees F
Vapor
True

24. How many amps can 12 g wire handle?
It will have a decrease in superheat
20 A
TXV
False

25. How do you calculate cfm?

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26. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
In series
True
Yes
4

27. How are round ducts connected to one another?
A piston type metering device
With a minimum of three evenly spaced self-tapping screws
Fiberglass
To remove humidity and lower dry bulb temperature

28. Do you need a vent on a pull-through evaporator?
Yes
Suction
Pistons
They are larger

29. When do you install an auxillary drain pan?
45-55%
Blended refrigerants
When it is above a conditioned space
A bypass duct or a dump zone

30. What standard weight copper tubing is most often used in the heating and air-conditioning industry?
L-type
Boil the liquid refrigerant out ot the oil within the crankcase
No
To lower the amount of pressure drop through the coil

31. What can cause a decrease in suction pressure on an air-conditioning system?
A dirty evaporator
150
Standard
Any amount

32. The evaporator is designed to remove what two types of heat?
They are physically larger
Duct with insulation on the inside
A dirty evaporator
Latent and sensible

33. The refrigerant within the evaporator will typically boil at what temperature when it is 75 degrees inside with a relative humidity of 50%?
Vapor
150
40 degrees F
A swaging tool

34. Do you need a vent on a push-through evaporator?
Yes
They are larger
105 degrees F
40 degrees F

35. What sort of pressure will a pull-through evaporator have?
True
25-ft or 50-ft
Negative
Stranded

36. What type of air conditioning system must be charged using the superheat method?
A piston type metering device
Belt drive and direct drive
Common
Yes

37. What is the design boiling point for most evaporator coils in residential air conditioning?
40 degrees F
Side-by-side and over-and-under
Individual return air systems and central return air systems
45-55%

38. The fan switch closes at what temperature?
2
Yes
Duct - electrical - and mechanical
140 degrees F

39. At what temperature does refrigerant condense in a high-efficiency unit?
Average feet per minute X area in square feet (H' x W'/144)
20 degrees above ambient
It rises
40 degrees F

40. 9' round duct has a ballpark cfm of what?
300
40 degrees F
It rises
25-ft or 50-ft

41. Which type of wire can handle a higher ampacity?
1/4'
Nitrogen with a small amount of refrigerant
A diffuser
Stranded

42. What is used to measure static air pressure in ducts.
Shorted winding - open winding - and grounded winding
2 minutes
Inclined manometer
Static pressure - velocity pressure - and total pressure

43. What are the three major power-consuming devices on an air-conditioning system?
Indoor fan motor - outdoor fan motor - and the compressor
Duct - electrical - and mechanical
Common
Outside diameter (OD)

44. What kind of metering device do high-efficiency units usually use?
Before the vent
Over 800 degrees F
TXV
Rise

45. Do you need a trap on a push-through evaporator?
No
40 degrees F
When it is a pull-through evaporator
30-35 degrees above ambient

46. If the suction pressure rises - what happens to the head pressure?
They are larger
It also rises
S-clips and drives (cleats)
20 A

47. What component changes refrigerant from a low pressure gas to a high pressure gas?
200
Compressor
Over 800 degrees F
Stranded

48. How many amps can 12 g wire handle?
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Stranded
20 A
Inclined manometer

49. How do you calculate the area of a circle?
4
Fiberglass
Common
Pi x radius squared

50. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
Dehydrated with caps on each end
It also rises
400
It will have a decrease in superheat