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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. What is the typical temperature difference between a high-efficiency condenser and the ambient temperature?
8
Btu/hr (output) / wattage (input)
300
20 degrees F

2. What kind of copper tubing is used for plumbing and heating applications?
Nominal-sized tubing
Subtract ambient temperature from 100
Duct with insulation on the inside
140 degrees F

3. What are the three major power-consuming devices on an air-conditioning system?
Indoor fan motor - outdoor fan motor - and the compressor
Individual return air systems and central return air systems
With 4' saddles
Pull a vacuum

4. How do you calculate EER?
45-55%
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
Btu/hr (output) / wattage (input)
30 A

5. What are the two ways that fresh air enters a structure?
100
TXV
Infiltration and ventilation
400

6. How is the high pressure switch wired with the low pressure switch?
8
40 degrees F
Fiberglass
In parallel

7. How do you calculate cfm?

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8. If the rpm's are 3450 - how many poles does the motor have?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
2
Inside diameter (ID)
Static pressure - velocity pressure - and total pressure

9. What are the two types of package units?
Negative
45 degrees F
Side-by-side and over-and-under
Pistons

10. What is the design boiling point for most evaporator coils in residential air conditioning?
False
105 degrees F
It will be high
40 degrees F

11. Which type of wire can handle a higher ampacity?
A band 4 inches or more in width
Stranded
They are physically larger
Duct with insulation on the inside

12. Pressure in ductwork is measured In what?
6
Inches of water column (in. WC)
Yes
It will be high

13. 10' round duct has a ballpark cfm of what?
400
Over/under and side by side
To remove humidity and lower dry bulb temperature
40 degrees F

14. The fan switch closes at what temperature?
140 degrees F
They are physically larger
300
Common

15. How are round ducts supported?

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16. On what terminal do you check amperage?
Common
Outside diameter (OD)
8-12 degrees F
Vapor

17. How is ACR tubing sized?
4
No
RLA/FLA x 5
Outside diameter (OD)

18. What component changes refrigerant from a low pressure gas to a high pressure gas?
Nominal-sized tubing
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
300
Compressor

19. What type of air conditioning system must be charged using the superheat method?
The suction line or the low-pressure side
4
A piston type metering device
A diffuser

20. What is used to measure static air pressure in ducts.
Infiltration and ventilation
Inclined manometer
When it is a pull-through evaporator
In series

21. How do you calculate ballpark superheat?
SEER includes the energy used in the start-up and shut-down cycles
A bypass duct or a dump zone
Before the vent
Subtract ambient temperature from 100

22. The A/C size is calculated by what?
A swaging tool
Yes
Duct - electrical - and mechanical
Heat load

23. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
A dirty evaporator
In series
Staples and tape
Vapor

24. Which is more efficient - a TXV or a fixed-orifice metering device?
1/4'
TXV
Static pressure - velocity pressure - and total pressure
A diffuser

25. At what temperature will soft solder melt?
A band 4 inches or more in width
Below 800 degrees F
Yes
A piston type metering device

26. 8' round duct has a ballpark cfm of what?
Dehydrated with caps on each end
200
With 4' saddles
Nitrogen with a small amount of refrigerant

27. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
2 minutes
Before the vent
Yes
45-55%

28. Why are some ACR tubing lines insulated?
15% silphos
Btu/hr (output) / wattage (input)
High
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line

29. What is considered normal operating conditions?
Yes
30-35 degrees above ambient
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Standard

30. Multiple-zone systems often use what to alleviate the problem of excess air when only some zones are calling for conditioning?
The takeoff fitting
6
Any amount
A bypass duct or a dump zone

31. How much superheat do you need to prevent liquid refrigerant from entering the compressor?
True
Any amount
20 degrees above ambient
Indoor fan motor - outdoor fan motor - and the compressor

32. What are the two types of return air systems in residential installations?
Individual return air systems and central return air systems
Yes
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Outside of the male fitting

33. How are high-efficiency condenser coils different from standard-efficiency condenser coils?
Positive
8-12 degrees F
400
They are physically larger

34. What kind of metering device do high-efficiency units usually use?
No
TXV
Yes
95 degrees F outside - 80 degrees F inside - and 50% relative humidity

35. If the rpm's are 1750 - how many poles does the motor have?
15% silphos
True
4
When it is a pull-through evaporator

36. How do you calculate the area of a circle?
SEER includes the energy used in the start-up and shut-down cycles
Pi x radius squared
The takeoff fitting
It rises

37. 8' round duct has a ballpark cfm of what?
Fiberglass
45 degrees F
200
Outside of the male fitting

38. Do you need a vent on a pull-through evaporator?
Negative
30 A
Yes
25-ft or 50-ft

39. 10 SEER is classified as what kind of efficiency?
It also rises
Yes
Standard
Duct with insulation on the inside

40. How is insulation around a duct rated?
Outside of the male fitting
With an are rating
20 degrees F
A diffuser

41. At what temperature does refrigerant condense in a standard-efficiency unit?
30-35 degrees above ambient
L-type
No
15 A

42. Will a dirty condenser cause a rise or fall in pressure?
Rise
Positive
40 degrees F
Dehydrated with caps on each end

43. Why is it necessary to have multiple refrigerant circuits in some evaporator coils?
With 4' saddles
A dirty evaporator
On the common terminal
To lower the amount of pressure drop through the coil

44. Do you need a vent on a push-through evaporator?
RLA/FLA x 5
Individual return air systems and central return air systems
300
Yes

45. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
Fiberglass
True
A diffuser
300

46. When do you install a trap on a drain line?
Staples and tape
Stranded
When it is a pull-through evaporator
They are physically larger

47. 10 SEER is classified as what kind of efficiency?
ACR (air-conditioning refrigeration) tubing
20 degrees above ambient
SEER includes the energy used in the start-up and shut-down cycles
Standard

48. The fan switch closes at what temperature?
Heat loss
100
Yes
140 degrees F

49. If the suction pressure rises - what happens to the head pressure?
It also rises
300
It will be low
Slugging

50. What is it called when liquid refrigerant gets into the compressor?
Yes
Indoor fan motor - outdoor fan motor - and the compressor
Slugging
5 degrees