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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 do you calculate cfm?

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2. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
Pull a vacuum
It will be low
45-55%
40 degrees F

3. What are the components of a hard-start kit?
Stranded
Potential relay and start capacitor
Any amount
They are larger

4. What is used to measure static air pressure in ducts.
Slugging
Inclined manometer
Individual return air systems and central return air systems
Dehydrated with caps on each end

5. What can cause a decrease in suction pressure on an air-conditioning system?
A dirty evaporator
With 4' saddles
A swaging tool
Slugging

6. What is the typical temperature difference between a standard-efficiency condenser and the ambient temperature?
400
30 degrees F
300
2

7. If the rpm's are 750 - how many poles does the motor have?
8
When the system is under pressure
Indoor fan motor - outdoor fan motor - and the compressor
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity

8. If the suction pressure rises - what happens to the head pressure?
To remove humidity and lower dry bulb temperature
TXV
It also rises
Yes

9. How do you calculate the area of a circle?
Inside diameter (ID)
Pi x radius squared
200
2 minutes

10. When do you install a trap on a drain line?
20 degrees F
When it is a pull-through evaporator
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
400

11. What is the typical temperature difference between a high-efficiency condenser and the ambient temperature?
Vapor
20 degrees F
With 4' saddles
Standard

12. The furnace size is calculated by what?
A diffuser
Heat loss
Rise
Duct - electrical - and mechanical

13. The refrigerant within the evaporator will typically boil at what temperature when it is 75 degrees inside with a relative humidity of 50%?
It will be low
Belt drive and direct drive
30-35 degrees above ambient
40 degrees F

14. What are the two functions of the air-conditioning system?
To remove humidity and lower dry bulb temperature
To lower the amount of pressure drop through the coil
105 degrees F
Blended refrigerants

15. What is the range for normal superheat and subcooling?
300
Belt drive and direct drive
They are physically larger
8-12 degrees F

16. 8' round duct has a ballpark cfm of what?
In parallel
200
High
1/4'

17. What is a package unit?
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
40 degrees F
Latent and sensible
2

18. What is considered normal operating conditions?
15 A
Slugging
It will be high
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity

19. What standard weight copper tubing is most often used in the heating and air-conditioning industry?
L-type
A dirty evaporator
45-55%
150

20. If the rpm's are 1050 - how many poles does the motor have?
300
Standard
6
To remove humidity and lower dry bulb temperature

21. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
It also rises
In series
Compressor
45 degrees F

22. What tool is used to expand the diameter of soft copper tubing
It rises
A swaging tool
18 gauge
False

23. At what temperature will brazing melt?
Compressor
Before the vent
Over 800 degrees F
A piston type metering device

24. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
45-55%
With an are rating
Nitrogen with a small amount of refrigerant
Compressor

25. Will a dirty condenser cause a rise or fall in pressure?
Rise
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Any amount
Outside diameter (OD)

26. What is the design boiling point for most evaporator coils in residential air conditioning?
Outside diameter (OD)
40 degrees F
They are physically larger
Inches of water column (in. WC)

27. What do you use to check for leaks?
40 degrees F
Rise
Nitrogen with a small amount of refrigerant
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity

28. Can refrigerant line sets be altered in length?
Pi x radius squared
Side-by-side and over-and-under
30 A
Yes

29. If the rpm's are 750 - how many poles does the motor have?
400
Any amount
Nitrogen with a small amount of refrigerant
8

30. What is the typical pressure differance across a TXV?
High
A swaging tool
100 psig
Over 800 degrees F

31. Which type of wire can handle a higher ampacity?
Dehydrated with caps on each end
It will be low
8
Stranded

32. What are the three crafts normally associated with an air-conditioned installation?
Duct - electrical - and mechanical
L-type
With an are rating
With 4' saddles

33. What are the two types of package units?
Side-by-side and over-and-under
Outside of the male fitting
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Btu/hr (output) / wattage (input)

34. Which is more efficient - a TXV or a fixed-orifice metering device?
TXV
They are physically larger
30-35 degrees above ambient
L-type

35. What kind of copper tubing is used for plumbing and heating applications?
Nominal-sized tubing
Static pressure - velocity pressure - and total pressure
High
Negative

36. If the rpm's are 1750 - how many poles does the motor have?
In parallel
Pistons
Inside diameter (ID)
4

37. If the rpm's are 3450 - how many poles does the motor have?
2
40 degrees F
By increasing the surface of the condenser coil
15% silphos

38. 9' round duct has a ballpark cfm of what?
Rise
Over 800 degrees F
300
TXV

39. What are the two types of blower drives?
It will have a decrease in superheat
Belt drive and direct drive
A piston type metering device
25-ft or 50-ft

40. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
15 A
In series
400
They are larger

41. At what temperature does refrigerant condense in a standard-efficiency unit?
30-35 degrees above ambient
2 minutes
150
15 A

42. How do you achieve high-efficiency?
By increasing the surface of the condenser coil
Any amount
Inside diameter (ID)
140 degrees F

43. What type of air conditioning system must be charged using the superheat method?
A piston type metering device
When it is above a conditioned space
5 degrees
6

44. The crankcase heater on an air-conditioning compressor is used to what?
To remove humidity and lower dry bulb temperature
Boil the liquid refrigerant out ot the oil within the crankcase
Inside diameter (ID)
A diffuser

45. What are the two ways that fresh air enters a structure?
Shorted winding - open winding - and grounded winding
2
ACR (air-conditioning refrigeration) tubing
Infiltration and ventilation

46. What kind of metering device do high-efficiency units usually use?
Blended refrigerants
45 degrees F
TXV
Infiltration and ventilation

47. In what length rolls is soft copper tubing normally available?
Over 800 degrees F
25-ft or 50-ft
They are larger
Pistons

48. How does ACR copper pipe come?
They are physically larger
Btu/hr (output) / wattage (input)
400
Dehydrated with caps on each end

49. Will a dirty condenser cause a rise or fall in pressure?
It will be high
When it is above a conditioned space
Rise
High

50. What type of air conditioning system must be charged using the superheat method?
SEER includes the energy used in the start-up and shut-down cycles
200
Fiberglass
A piston type metering device