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. The fan switch closes at what temperature?
Positive
140 degrees F
1/4'
With a minimum of three evenly spaced self-tapping screws

2. The load on the evaporater will effect which pressure?
45-55%
When it is a pull-through evaporator
Suction
30-35 degrees above ambient

3. What is considered normal operating conditions?
Indoor fan motor - outdoor fan motor - and the compressor
6
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
300

4. What kind of copper tubing is used for refrigeration or air-conditioning applications?
A swaging tool
ACR (air-conditioning refrigeration) tubing
Before the vent
They are physically larger

5. How are round ducts supported?

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6. How do you calculate cfm?

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7. At what temperature does refrigerant condense in a high-efficiency unit?
Staples and tape
TXV
20 degrees above ambient
Infiltration and ventilation

8. When must a copper joint never be soldered or brazed?
When the system is under pressure
Subtract ambient temperature from 100
False
L-type

9. At what temperature will brazing melt?
TXV
Over 800 degrees F
1/4'
Btu/hr (output) / wattage (input)

10. How is nominal-sized tubing sized?
6
Inside diameter (ID)
A piston type metering device
True

11. Do you need a vent on a push-through evaporator?
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Yes
Negative
20 degrees F

12. What kind of refrigeratnts must be added in liquid form?
Blended refrigerants
The takeoff fitting
False
Below 800 degrees F

13. 10' round duct has a ballpark cfm of what?
400
Yes
Common
40 degrees F

14. What are the two basic duct connection configurations for package units supply and return air ducts?
They are physically larger
200
Over/under and side by side
300

15. Sections of duct board can be fastened together with what?
Staples and tape
Nominal-sized tubing
Vapor
The takeoff fitting

16. Which type of wire can handle a higher ampacity?
The suction line or the low-pressure side
Yes
Indoor fan motor - outdoor fan motor - and the compressor
Stranded

17. The crankcase heater on an air-conditioning compressor is used to what?
TXV
Boil the liquid refrigerant out ot the oil within the crankcase
Over 800 degrees F
False

18. Superheat should never be below how many degrees
5 degrees
20 A
Positive
A dirty evaporator

19. How much superheat do you need to prevent liquid refrigerant from entering the compressor?
By increasing the surface of the condenser coil
Any amount
They are physically larger
Potential relay and start capacitor

20. What is lined duct?
High
Duct with insulation on the inside
15 A
TXV

21. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
A diffuser
Compressor
It will have a decrease in superheat
45-55%

22. 9' round duct has a ballpark cfm of what?
300
To lower the amount of pressure drop through the coil
1/4'
A band 4 inches or more in width

23. 8' round duct has a ballpark cfm of what?
200
Over/under and side by side
Inches of water column (in. WC)
Standard

24. How is insulation around a duct rated?
40 degrees F
25-ft or 50-ft
With an are rating
20 degrees F

25. When do you install a trap on a drain line?
Compressor
When it is a pull-through evaporator
It rises
Yes

26. What percentage silver do you need to use for an are-410 system?
30-35 degrees above ambient
15% silphos
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
No

27. What distributes supply air to a room in a structure?
8
Belt drive and direct drive
A diffuser
30 A

28. Will a dirty condenser cause a rise or fall in pressure?
Rise
Duct - electrical - and mechanical
Any amount
140 degrees F

29. If pressure rises - what happens to the superheat?
It rises
Positive
Pull a vacuum
Inches of water column (in. WC)

30. What do you use to connect square and rectangular ductboard together?
2
False
S-clips and drives (cleats)
They are larger

31. What are the two functions of the air-conditioning system?
To remove humidity and lower dry bulb temperature
Dehydrated with caps on each end
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
ACR (air-conditioning refrigeration) tubing

32. On what terminal do you check amperage?
Common
Btu/hr (output) / wattage (input)
140 degrees F
Stranded

33. How many amps can 10 g wire handle?
30 A
A swaging tool
45-55%
8

34. The A/C size is calculated by what?
Heat load
Stranded
Inches of water column (in. WC)
In series

35. What is it called when liquid refrigerant gets into the compressor?
Nominal-sized tubing
18 gauge
Slugging
A bypass duct or a dump zone

36. Do you need a vent on a push-through evaporator?
Yes
A band 4 inches or more in width
40 A
5 degrees

37. 9' round duct has a ballpark cfm of what?
It will be low
Latent and sensible
300
140 degrees F

38. At what temperature will soft solder melt?
Below 800 degrees F
18 gauge
6
It rises

39. What gauge is thermostat wire?
Over/under and side by side
Pull a vacuum
400
18 gauge

40. Does a package unit come from the factory pre-charged?
Yes
2
Pull a vacuum
Inches of water column (in. WC)

41. 10 SEER is classified as what kind of efficiency?
Standard
Duct - electrical - and mechanical
A band 4 inches or more in width
Negative

42. How long should you leave a system off once you kill power before restarting it?
2
2 minutes
Duct with insulation on the inside
40 degrees F

43. What do you use to check for leaks?
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
When it is a pull-through evaporator
A bypass duct or a dump zone
Nitrogen with a small amount of refrigerant

44. How will too much refrigerant effect subcooling?
It will be high
In parallel
A band 4 inches or more in width
With 4' saddles

45. 10' round duct has a ballpark cfm of what?
With an are rating
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
400
Staples and tape

46. When do you install an auxillary drain pan?
They are larger
When it is above a conditioned space
Inclined manometer
Blended refrigerants

47. If the rpm's are 750 - how many poles does the motor have?
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
8
They are physically larger

48. What is the typical pressure differance across a TXV?
Dehydrated with caps on each end
100 psig
With a minimum of three evenly spaced self-tapping screws
Standard

49. What is the typical temperature difference between a high-efficiency condenser and the ambient temperature?
With 4' saddles
A dirty evaporator
High
20 degrees F

50. 8' round duct has a ballpark cfm of what?
200
In series
Staples and tape
When the system is under pressure