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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. The evaporator is designed to remove what two types of heat?
Latent and sensible
Subtract ambient temperature from 100
Suction
RLA/FLA x 5

2. How is insulation around a duct rated?
Infiltration and ventilation
15% silphos
With an are rating
25-ft or 50-ft

3. How will too much refrigerant effect superheat?
Belt drive and direct drive
200
Suction
It will be low

4. Do you need a trap on a pull-through evaporator?
400
Slugging
Yes
400

5. How do you calculate ballpark superheat?
Subtract ambient temperature from 100
By increasing the surface of the condenser coil
No
It also rises

6. What is the normal evaporator temperature?
Over/under and side by side
Average feet per minute X area in square feet (H' x W'/144)
Stranded
45 degrees F

7. What do you use to connect square and rectangular ductboard together?
No
S-clips and drives (cleats)
True
A swaging tool

8. What are the four materials used to make duct?
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
Suction
40 A
15% silphos

9. How is flexible duct supported?
When it is a pull-through evaporator
A band 4 inches or more in width
Subtract ambient temperature from 100
S-clips and drives (cleats)

10. Most duct insulation is made of what?
The takeoff fitting
Compressor
Fiberglass
Heat load

11. How do you calculate cfm?

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12. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
Compressor
18 gauge
True
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.

13. How do you calculate LRA?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
A band 4 inches or more in width
SEER includes the energy used in the start-up and shut-down cycles
RLA/FLA x 5

14. What gauge is thermostat wire?
18 gauge
Nominal-sized tubing
Inches of water column (in. WC)
Fiberglass

15. How many amps can 10 g wire handle?
30 A
100 psig
Nitrogen with a small amount of refrigerant
Pistons

16. The load on the evaporater will effect which pressure?
25-ft or 50-ft
45 degrees F
Suction
Yes

17. How many amps can 8 g wire handle?
40 A
Common
When it is above a conditioned space
25-ft or 50-ft

18. The fan switch opens at what temperature?
105 degrees F
100 psig
Below 800 degrees F
30-35 degrees above ambient

19. What can cause a decrease in suction pressure on an air-conditioning system?
Nitrogen with a small amount of refrigerant
A dirty evaporator
SEER includes the energy used in the start-up and shut-down cycles
Infiltration and ventilation

20. How many BTU's per ton?
4
12000
The takeoff fitting
When the system is under pressure

21. Why is it necessary to have multiple refrigerant circuits in some evaporator coils?
The takeoff fitting
4
To lower the amount of pressure drop through the coil
100 psig

22. How do you achieve high-efficiency?
40 degrees F
Belt drive and direct drive
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
By increasing the surface of the condenser coil

23. What are the three ways a motor can fail electrically?
High
Shorted winding - open winding - and grounded winding
15 A
With an are rating

24. What standard weight copper tubing is most often used in the heating and air-conditioning industry?
Rise
L-type
It also rises
45 degrees F

25. If the rpm's are 750 - how many poles does the motor have?
20 degrees above ambient
8
400
Fiberglass

26. What do you use to check for leaks?
Belt drive and direct drive
Nitrogen with a small amount of refrigerant
1/4'
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line

27. What sort of pressure will a push-through evaporator have?
Positive
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
RLA/FLA x 5
18 gauge

28. Do you need a vent on a pull-through evaporator?
Pi x radius squared
30 degrees F
150
Yes

29. At what temperature will brazing melt?
1/4'
Over 800 degrees F
True
ACR (air-conditioning refrigeration) tubing

30. How do you calculate ballpark superheat?
Yes
140 degrees F
When the system is under pressure
Subtract ambient temperature from 100

31. What are the two functions of the air-conditioning system?
It will have a decrease in superheat
The takeoff fitting
To remove humidity and lower dry bulb temperature
It will be low

32. How are the condenser coils different on a high-efficiency unit?
They are larger
Below 800 degrees F
Side-by-side and over-and-under
Inside diameter (ID)

33. What is the name of the fitting where the branch line leaves the duct?
Nitrogen with a small amount of refrigerant
1/4'
The takeoff fitting
100 psig

34. When do you install an auxillary drain pan?
TXV
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
With a minimum of three evenly spaced self-tapping screws
When it is above a conditioned space

35. The fan switch closes at what temperature?
Heat load
400
With 4' saddles
140 degrees F

36. How long should you leave a system off once you kill power before restarting it?
Static pressure - velocity pressure - and total pressure
With a minimum of three evenly spaced self-tapping screws
Slugging
2 minutes

37. What is the design boiling point for most evaporator coils in residential air conditioning?
200
40 degrees F
They are physically larger
Outside of the male fitting

38. How are high-efficiency condenser coils different from standard-efficiency condenser coils?
It will be high
They are physically larger
Over 800 degrees F
Outside of the male fitting

39. How is flexible duct supported?
6
L-type
A band 4 inches or more in width
The takeoff fitting

40. At what temperature will soft solder melt?
Below 800 degrees F
Heat load
Boil the liquid refrigerant out ot the oil within the crankcase
Positive

41. What is used to measure static air pressure in ducts.
Yes
Btu/hr (output) / wattage (input)
2
Inclined manometer

42. The crankcase heater on an air-conditioning compressor is used to what?
12000
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
It rises
Boil the liquid refrigerant out ot the oil within the crankcase

43. What are the two types of return air systems in residential installations?
Suction
Individual return air systems and central return air systems
Positive
With 4' saddles

44. 7' round duct has a ballpark cfm of what?
40 degrees F
Before the vent
150
Side-by-side and over-and-under

45. What do you use to connect square and rectangular ductboard together?
100
True
Belt drive and direct drive
S-clips and drives (cleats)

46. How do you calculate the area of a circle?
Pistons
Pi x radius squared
40 A
ACR (air-conditioning refrigeration) tubing

47. What is the difference between SEER and EER?
100 psig
Yes
It also rises
SEER includes the energy used in the start-up and shut-down cycles

48. Where do you install a trap on a drain line?
Before the vent
Inclined manometer
TXV
In parallel

49. Does a package unit come from the factory pre-charged?
Yes
Average feet per minute X area in square feet (H' x W'/144)
Staples and tape
105 degrees F

50. Which is more efficient - a TXV or a fixed-orifice metering device?
TXV
The suction line or the low-pressure side
Slugging
SEER includes the energy used in the start-up and shut-down cycles