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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 many amps can 14 g wire handle?
20 A
L-type
15 A
Stranded

2. What do you use to check for leaks?
Stranded
A diffuser
Nitrogen with a small amount of refrigerant
Duct - electrical - and mechanical

3. How are the condenser coils different on a high-efficiency unit?
Yes
S-clips and drives (cleats)
They are larger
TXV

4. How many BTU's per ton?
Pi x radius squared
To lower the amount of pressure drop through the coil
With a minimum of three evenly spaced self-tapping screws
12000

5. What is lined duct?
Standard
To lower the amount of pressure drop through the coil
Duct with insulation on the inside
40 A

6. Why is it necessary to have multiple refrigerant circuits in some evaporator coils?
A band 4 inches or more in width
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
To lower the amount of pressure drop through the coil
Infiltration and ventilation

7. What is the normal evaporator temperature?
Stranded
20 degrees F
30 A
45 degrees F

8. What kind of refrigeratnts must be added in liquid form?
Over/under and side by side
Individual return air systems and central return air systems
100
Blended refrigerants

9. How do you calculate cfm?

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10. How do you calculate cfm?

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11. What is the name of the fitting where the branch line leaves the duct?
40 degrees F
Pull a vacuum
The takeoff fitting
TXV

12. 7' round duct has a ballpark cfm of what?
Suction
It rises
Pull a vacuum
150

13. What is the typical temperature difference between a high-efficiency condenser and the ambient temperature?
20 degrees F
45 degrees F
Yes
Pistons

14. How is insulation around a duct rated?
With an are rating
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
Individual return air systems and central return air systems
18 gauge

15. In what state is the refrigerant in the compressor?
Dehydrated with caps on each end
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Vapor
In series

16. What type of air conditioning system must be charged using the superheat method?
A piston type metering device
15 A
In series
Boil the liquid refrigerant out ot the oil within the crankcase

17. What kind of copper tubing is used for plumbing and heating applications?
It will be high
TXV
A dirty evaporator
Nominal-sized tubing

18. What are normal conditions - as defined by the ARI.
150
It will be low
100 psig
95 degrees F outside - 80 degrees F inside - and 50% relative humidity

19. What is it called when liquid refrigerant gets into the compressor?
Slugging
Stranded
Compressor
False

20. What are the two ways that fresh air enters a structure?
Outside of the male fitting
When it is above a conditioned space
Infiltration and ventilation
4

21. At what temperature will brazing melt?
Slugging
Over 800 degrees F
8-12 degrees F
A diffuser

22. What are the two functions of the air-conditioning system?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
ACR (air-conditioning refrigeration) tubing
Shorted winding - open winding - and grounded winding
To remove humidity and lower dry bulb temperature

23. What are the three pressures created by moving air in ductwork?
Static pressure - velocity pressure - and total pressure
Subtract ambient temperature from 100
30-35 degrees above ambient
20 A

24. 10' round duct has a ballpark cfm of what?
25-ft or 50-ft
With an are rating
When it is above a conditioned space
400

25. What percentage silver do you need to use for an are-410 system?
15% silphos
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
It will have a decrease in superheat
Positive

26. How many amps can 8 g wire handle?
With an are rating
40 A
It also rises
A diffuser

27. Do you need a vent on a pull-through evaporator?
40 degrees F
Yes
It will have a decrease in superheat
Inside diameter (ID)

28. What are the three pressures created by moving air in ductwork?
Negative
Blended refrigerants
Static pressure - velocity pressure - and total pressure
40 degrees F

29. What kind of metering device do high-efficiency units usually use?
Before the vent
TXV
30 degrees F
It will be high

30. What distributes supply air to a room in a structure?
A diffuser
Negative
18 gauge
Latent and sensible

31. What is the design boiling point for most evaporator coils in residential air conditioning?
40 degrees F
Heat load
Outside of the male fitting
False

32. How is flexible duct supported?
Pistons
A band 4 inches or more in width
In series
In parallel

33. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
Outside diameter (OD)
Yes
True
Stranded

34. Do you need a trap on a pull-through evaporator?
It will be low
Vapor
Pistons
Yes

35. What are the three ways a motor can fail electrically?
Shorted winding - open winding - and grounded winding
400
30 A
TXV

36. Do you need a vent on a pull-through evaporator?
Fiberglass
2
100 psig
Yes

37. Where do you install a trap on a drain line?
Before the vent
30 degrees F
30 A
4

38. What kind of refrigeratnts must be added in liquid form?
2
Blended refrigerants
Staples and tape
Average feet per minute X area in square feet (H' x W'/144)

39. How many amps can 12 g wire handle?
45-55%
400
True
20 A

40. Can refrigerant line sets be altered in length?
On the common terminal
In parallel
140 degrees F
Yes

41. Where do you apply flux when soldering?
It will be low
Inches of water column (in. WC)
TXV
Outside of the male fitting

42. What is the difference between SEER and EER?
SEER includes the energy used in the start-up and shut-down cycles
Duct - electrical - and mechanical
40 A
It will have a decrease in superheat

43. If the suction pressure rises - what happens to the head pressure?
2
2 minutes
400
It also rises

44. If the rpm's are 1750 - how many poles does the motor have?
The takeoff fitting
4
When it is above a conditioned space
With an are rating

45. How will too much refrigerant effect subcooling?
20 degrees F
It will be high
20 degrees above ambient
To remove humidity and lower dry bulb temperature

46. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
By increasing the surface of the condenser coil
45-55%
Pistons
Subtract ambient temperature from 100

47. Where do you apply flux when soldering?
RLA/FLA x 5
High
Outside of the male fitting
Boil the liquid refrigerant out ot the oil within the crankcase

48. Why are some ACR tubing lines insulated?
300
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
4
By increasing the surface of the condenser coil

49. What are the two basic duct connection configurations for package units supply and return air ducts?
45-55%
140 degrees F
2 minutes
Over/under and side by side

50. Can refrigerant line sets be altered in length?
Blended refrigerants
It will be low
L-type
Yes