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. 6' round duct has a ballpark cfm of what?
1/4'
They are physically larger
A swaging tool
100

2. At what temperature will brazing melt?
Over 800 degrees F
2 minutes
Inclined manometer
In parallel

3. What tool is used to expand the diameter of soft copper tubing
A swaging tool
Heat load
300
A piston type metering device

4. How do you calculate LRA?
Pistons
When it is above a conditioned space
20 A
RLA/FLA x 5

5. When do you install an auxillary drain pan?
Infiltration and ventilation
15 A
A piston type metering device
When it is above a conditioned space

6. How are round ducts supported?

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7. Do you need a vent on a pull-through evaporator?
No
4
Yes
Duct - electrical - and mechanical

8. What are the three ways a motor can fail electrically?
Shorted winding - open winding - and grounded winding
True
Fiberglass
High

9. 7' round duct has a ballpark cfm of what?
Yes
150
Pistons
False

10. What kind of copper tubing is used for plumbing and heating applications?
In series
Btu/hr (output) / wattage (input)
Boil the liquid refrigerant out ot the oil within the crankcase
Nominal-sized tubing

11. The A/C size is calculated by what?
Fiberglass
Heat load
Nominal-sized tubing
300

12. How do you calculate cfm?

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13. The evaporator is designed to remove what two types of heat?
30 degrees F
20 degrees above ambient
25-ft or 50-ft
Latent and sensible

14. What is considered normal operating conditions?
Potential relay and start capacitor
Dehydrated with caps on each end
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
It will be low

15. 10' round duct has a ballpark cfm of what?
100 psig
400
Belt drive and direct drive
Belt drive and direct drive

16. The load on the evaporater will effect which pressure?
False
Suction
150
Yes

17. Will a dirty condenser cause a rise or fall in pressure?
100
L-type
Rise
With an are rating

18. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
It will have a decrease in superheat
Pi x radius squared
A band 4 inches or more in width
It also rises

19. What sort of pressure will a push-through evaporator have?
It will have a decrease in superheat
Side-by-side and over-and-under
ACR (air-conditioning refrigeration) tubing
Positive

20. The crankcase heater on an air-conditioning compressor is used to what?
Side-by-side and over-and-under
Boil the liquid refrigerant out ot the oil within the crankcase
With a minimum of three evenly spaced self-tapping screws
40 A

21. The furnace size is calculated by what?
8-12 degrees F
Heat loss
With a minimum of three evenly spaced self-tapping screws
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.

22. How is insulation around a duct rated?
With an are rating
Standard
When it is a pull-through evaporator
Before the vent

23. Do you need a trap on a pull-through evaporator?
Potential relay and start capacitor
8-12 degrees F
Yes
Blended refrigerants

24. What is the design boiling point for most evaporator coils in residential air conditioning?
40 degrees F
In series
The suction line or the low-pressure side
300

25. What are the components of a hard-start kit?
To lower the amount of pressure drop through the coil
TXV
Potential relay and start capacitor
The takeoff fitting

26. How long should you leave a system off once you kill power before restarting it?
25-ft or 50-ft
100 psig
Yes
2 minutes

27. Superheat should never be below how many degrees
Average feet per minute X area in square feet (H' x W'/144)
5 degrees
S-clips and drives (cleats)
A diffuser

28. What standard weight copper tubing is most often used in the heating and air-conditioning industry?
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
TXV
L-type
6

29. 9' round duct has a ballpark cfm of what?
300
8
20 A
Blended refrigerants

30. What is it called when liquid refrigerant gets into the compressor?
Slugging
20 degrees above ambient
Individual return air systems and central return air systems
6

31. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
It also rises
45-55%

32. Which is more efficient - a TXV or a fixed-orifice metering device?
It will be high
Nitrogen with a small amount of refrigerant
TXV
It will be high

33. Multiple-zone systems often use what to alleviate the problem of excess air when only some zones are calling for conditioning?
Blended refrigerants
Suction
A bypass duct or a dump zone
Over 800 degrees F

34. What is the name of the fitting where the branch line leaves the duct?
The takeoff fitting
Average feet per minute X area in square feet (H' x W'/144)
In parallel
1/4'

35. What are the four materials used to make duct?
Dehydrated with caps on each end
They are larger
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
Standard

36. When must a copper joint never be soldered or brazed?
It will have a decrease in superheat
When the system is under pressure
In parallel
TXV

37. Do you need a trap on a push-through evaporator?
Over 800 degrees F
Before the vent
ACR (air-conditioning refrigeration) tubing
No

38. How many BTU's per ton?
Indoor fan motor - outdoor fan motor - and the compressor
12000
Individual return air systems and central return air systems
They are larger

39. Where is insulation used on copper tubing used for air-conditioning?
Shorted winding - open winding - and grounded winding
Outside diameter (OD)
Outside of the male fitting
The suction line or the low-pressure side

40. How much superheat do you need to prevent liquid refrigerant from entering the compressor?
40 degrees F
Latent and sensible
45 degrees F
Any amount

41. In what length rolls is soft copper tubing normally available?
Duct with insulation on the inside
25-ft or 50-ft
With a minimum of three evenly spaced self-tapping screws
Outside diameter (OD)

42. What percentage silver do you need to use for an are-410 system?
The takeoff fitting
150
12000
15% silphos

43. What is the range for normal superheat and subcooling?
8-12 degrees F
A swaging tool
ACR (air-conditioning refrigeration) tubing
It will have a decrease in superheat

44. When do you install an auxillary drain pan?
When it is above a conditioned space
With a minimum of three evenly spaced self-tapping screws
TXV
30 degrees F

45. What is the design boiling point for most evaporator coils in residential air conditioning?
In series
40 degrees F
To remove humidity and lower dry bulb temperature
Sheet metal - galvanized sheet metal - fiberglass - and flexduct

46. How long should you leave a system off once you kill power before restarting it?
Before the vent
2 minutes
30 degrees F
False

47. The compressor is cooled by liquid refrigerant. (True of False)
It will have a decrease in superheat
High
Yes
False

48. At what temperature will brazing melt?
L-type
Over 800 degrees F
8
20 A

49. How many amps can 8 g wire handle?
A piston type metering device
Fiberglass
40 A
A bypass duct or a dump zone

50. At what temperature will soft solder melt?
Below 800 degrees F
TXV
Positive
Staples and tape