Test your basic knowledge |

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. 10' round duct has a ballpark cfm of what?
Outside diameter (OD)
Individual return air systems and central return air systems
With an are rating
400

2. What do you use to check for leaks?
With a minimum of three evenly spaced self-tapping screws
Nitrogen with a small amount of refrigerant
5 degrees
Yes

3. How do you calculate LRA?
It also rises
2
40 degrees F
RLA/FLA x 5

4. How will too much refrigerant effect superheat?
High
It will be low
Inclined manometer
8-12 degrees F

5. If pressure rises - what happens to the superheat?
Inches of water column (in. WC)
Subtract ambient temperature from 100
15 A
It rises

6. Will a dirty condenser cause a rise or fall in pressure?
By increasing the surface of the condenser coil
To remove humidity and lower dry bulb temperature
Rise
Nominal-sized tubing

7. What type of air conditioning system must be charged using the superheat method?
A piston type metering device
Before the vent
2
Negative

8. At what temperature does refrigerant condense in a standard-efficiency unit?
30-35 degrees above ambient
Latent and sensible
Nominal-sized tubing
1/4'

9. The load on the evaporater will effect which pressure?
100 psig
Suction
Common
Average feet per minute X area in square feet (H' x W'/144)

10. How many cfm per ton?
400
Shorted winding - open winding - and grounded winding
Yes
30 A

11. Where do you install a trap on a drain line?
Before the vent
8-12 degrees F
When it is a pull-through evaporator
A bypass duct or a dump zone

12. How does ACR copper pipe come?
Dehydrated with caps on each end
Potential relay and start capacitor
Common
300

13. 10' round duct has a ballpark cfm of what?
400
30-35 degrees above ambient
When it is above a conditioned space
30-35 degrees above ambient

14. What are the three pressures created by moving air in ductwork?
105 degrees F
Static pressure - velocity pressure - and total pressure
It will be high
A diffuser

15. Do you need a vent on a pull-through evaporator?
L-type
4
Yes
Pi x radius squared

16. What do you do after you braze a system?
Boil the liquid refrigerant out ot the oil within the crankcase
Pull a vacuum
Inclined manometer
ACR (air-conditioning refrigeration) tubing

17. What are the three crafts normally associated with an air-conditioned installation?
Subtract ambient temperature from 100
Duct - electrical - and mechanical
In series
20 A

18. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
A swaging tool
By increasing the surface of the condenser coil
45-55%
Positive

19. In what length rolls is soft copper tubing normally available?
Yes
25-ft or 50-ft
Blended refrigerants
Side-by-side and over-and-under

20. How are the condenser coils different on a high-efficiency unit?
They are larger
With a minimum of three evenly spaced self-tapping screws
20 degrees F
Stranded

21. At what temperature will soft solder melt?
When it is a pull-through evaporator
Staples and tape
True
Below 800 degrees F

22. What kind of refrigeratnts must be added in liquid form?
S-clips and drives (cleats)
Blended refrigerants
A dirty evaporator
A band 4 inches or more in width

23. When do you install an auxillary drain pan?
Pi x radius squared
Btu/hr (output) / wattage (input)
When it is above a conditioned space
Vapor

24. In what state is the refrigerant in the compressor?
To lower the amount of pressure drop through the coil
It will be high
100 psig
Vapor

25. How do you calculate ballpark superheat?
They are physically larger
Latent and sensible
Subtract ambient temperature from 100
100

26. On what terminal do you check amperage?
Common
40 degrees F
Inside diameter (ID)
Inside diameter (ID)

27. When do you install a trap on a drain line?
Vapor
When it is a pull-through evaporator
Yes
The takeoff fitting

28. Why is it necessary to have multiple refrigerant circuits in some evaporator coils?
18 gauge
Yes
45-55%
To lower the amount of pressure drop through the coil

29. What kind of refrigeratnts must be added in liquid form?
Blended refrigerants
Individual return air systems and central return air systems
They are physically larger
100 psig

30. How is flexible duct supported?
Heat load
With a minimum of three evenly spaced self-tapping screws
A band 4 inches or more in width
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.

31. How are round ducts supported?

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32. How do you calculate cfm?

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33. Which is more efficient - a TXV or a fixed-orifice metering device?
TXV
Yes
A diffuser
Belt drive and direct drive

34. What is considered normal operating conditions?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
18 gauge
In series
Pi x radius squared

35. Most duct insulation is made of what?
Fiberglass
Pull a vacuum
Positive
The suction line or the low-pressure side

36. How is nominal-sized tubing sized?
Inside diameter (ID)
Side-by-side and over-and-under
Subtract ambient temperature from 100
TXV

37. How is ACR tubing sized?
2
Outside diameter (OD)
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Below 800 degrees F

38. What are the two basic duct connection configurations for package units supply and return air ducts?
Pull a vacuum
15 A
It will have a decrease in superheat
Over/under and side by side

39. Pressure in ductwork is measured In what?
Common
Inches of water column (in. WC)
Below 800 degrees F
A swaging tool

40. What are the two functions of the air-conditioning system?
TXV
Pi x radius squared
To remove humidity and lower dry bulb temperature
Latent and sensible

41. Does a package unit come from the factory pre-charged?
2
Yes
When it is a pull-through evaporator
TXV

42. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
True
Static pressure - velocity pressure - and total pressure
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Common

43. How is the high pressure switch wired with the low pressure switch?
False
8-12 degrees F
In parallel
Heat loss

44. What kind of metering device do high-efficiency units usually use?
TXV
Fiberglass
400
When it is a pull-through evaporator

45. What are the three major power-consuming devices on an air-conditioning system?
TXV
A band 4 inches or more in width
8-12 degrees F
Indoor fan motor - outdoor fan motor - and the compressor

46. What are the components of a hard-start kit?
Inside diameter (ID)
Potential relay and start capacitor
Latent and sensible
A piston type metering device

47. How do you calculate ballpark superheat?
Pull a vacuum
The suction line or the low-pressure side
Subtract ambient temperature from 100
6

48. If pressure rises - what happens to the superheat?
Stranded
Potential relay and start capacitor
It rises
When the system is under pressure

49. The A/C size is calculated by what?
To remove humidity and lower dry bulb temperature
Heat load
Average feet per minute X area in square feet (H' x W'/144)
In parallel

50. What is the name of the fitting where the branch line leaves the duct?
A swaging tool
The takeoff fitting
Staples and tape
Over/under and side by side