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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. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
Individual return air systems and central return air systems
Dehydrated with caps on each end
It will have a decrease in superheat
100

2. What sort of pressure will a push-through evaporator have?
Before the vent
1/4'
Positive
Stranded

3. How long should you leave a system off once you kill power before restarting it?
Blended refrigerants
Potential relay and start capacitor
2 minutes
The suction line or the low-pressure side

4. 7' round duct has a ballpark cfm of what?
150
When it is a pull-through evaporator
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Nominal-sized tubing

5. What do you do after you braze a system?
Pull a vacuum
15% silphos
105 degrees F
S-clips and drives (cleats)

6. What is the typical pressure differance across a TXV?
They are physically larger
L-type
100 psig
105 degrees F

7. How do you calculate the area of a circle?
100
2
Pi x radius squared
Yes

8. What tool is used to expand the diameter of soft copper tubing
Duct with insulation on the inside
L-type
A swaging tool
SEER includes the energy used in the start-up and shut-down cycles

9. What are the three major power-consuming devices on an air-conditioning system?
Inches of water column (in. WC)
40 degrees F
Indoor fan motor - outdoor fan motor - and the compressor
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity

10. If the suction pressure rises - what happens to the head pressure?
100 psig
Nitrogen with a small amount of refrigerant
2
It also rises

11. Do you need a vent on a pull-through evaporator?
Yes
2 minutes
Common
40 degrees F

12. What is the typical temperature difference between a high-efficiency condenser and the ambient temperature?
20 degrees F
Individual return air systems and central return air systems
The suction line or the low-pressure side
With a minimum of three evenly spaced self-tapping screws

13. Which type of wire can handle a higher ampacity?
Stranded
Static pressure - velocity pressure - and total pressure
A diffuser
A band 4 inches or more in width

14. What are the components of a hard-start kit?
They are physically larger
Potential relay and start capacitor
400
Yes

15. How do you calculate LRA?
They are physically larger
A diffuser
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
RLA/FLA x 5

16. Which is more efficient - a TXV or a fixed-orifice metering device?
400
Any amount
In series
TXV

17. What is considered normal operating conditions?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
With an are rating
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Subtract ambient temperature from 100

18. In what state is the refrigerant in the compressor?
300
45-55%
Vapor
20 A

19. Which is more efficient - a TXV or a fixed-orifice metering device?
15% silphos
It rises
TXV
It will have a decrease in superheat

20. How do you calculate cfm?

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21. How many amps can 10 g wire handle?
To lower the amount of pressure drop through the coil
Pi x radius squared
Boil the liquid refrigerant out ot the oil within the crankcase
30 A

22. The load on the evaporater will effect which pressure?
Dehydrated with caps on each end
Suction
On the common terminal
95 degrees F outside - 80 degrees F inside - and 50% relative humidity

23. What is it called when liquid refrigerant gets into the compressor?
TXV
Slugging
TXV
8

24. In what length rolls is soft copper tubing normally available?
Common
25-ft or 50-ft
Duct with insulation on the inside
ACR (air-conditioning refrigeration) tubing

25. Where do you apply flux when soldering?
Subtract ambient temperature from 100
Inclined manometer
45-55%
Outside of the male fitting

26. What kind of copper tubing is used for plumbing and heating applications?
Nominal-sized tubing
Outside of the male fitting
Latent and sensible
Yes

27. What kind of copper tubing is used for plumbing and heating applications?
Nominal-sized tubing
15 A
A piston type metering device
TXV

28. What do you use to check for leaks?
Subtract ambient temperature from 100
Nitrogen with a small amount of refrigerant
30-35 degrees above ambient
Standard

29. If pressure rises - what happens to the superheat?
30 A
It rises
High
When it is a pull-through evaporator

30. Where do you check the amps on a motor?
Heat load
On the common terminal
S-clips and drives (cleats)
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.

31. Does a package unit come from the factory pre-charged?
False
Yes
Nitrogen with a small amount of refrigerant
40 degrees F

32. What kind of metering device do high-efficiency units usually use?
S-clips and drives (cleats)
Duct - electrical - and mechanical
150
TXV

33. What sort of pressure will a push-through evaporator have?
20 degrees F
Positive
Nominal-sized tubing
Infiltration and ventilation

34. How do you calculate EER?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Btu/hr (output) / wattage (input)
Blended refrigerants
6

35. What do you use to connect square and rectangular ductboard together?
Below 800 degrees F
S-clips and drives (cleats)
SEER includes the energy used in the start-up and shut-down cycles
Inches of water column (in. WC)

36. How does ACR copper pipe come?
SEER includes the energy used in the start-up and shut-down cycles
Common
It will have a decrease in superheat
Dehydrated with caps on each end

37. What kind of refrigeratnts must be added in liquid form?
Btu/hr (output) / wattage (input)
105 degrees F
Blended refrigerants
15% silphos

38. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
45-55%
8-12 degrees F
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line

39. What are the two types of return air systems in residential installations?
6
A bypass duct or a dump zone
Individual return air systems and central return air systems
30 A

40. Do you need a trap on a push-through evaporator?
Positive
Yes
True
No

41. Why are some ACR tubing lines insulated?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
6
45-55%
Subtract ambient temperature from 100

42. If the rpm's are 1750 - how many poles does the motor have?
4
TXV
Infiltration and ventilation
It also rises

43. How many amps can 8 g wire handle?
40 A
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
On the common terminal
40 degrees F

44. How is the high pressure switch wired with the low pressure switch?
Vapor
In parallel
Rise
45 degrees F

45. What is the name of the fitting where the branch line leaves the duct?
The takeoff fitting
5 degrees
Compressor
Sheet metal - galvanized sheet metal - fiberglass - and flexduct

46. The furnace size is calculated by what?
It will have a decrease in superheat
Heat loss
Suction
Compressor

47. Sections of duct board can be fastened together with what?
Staples and tape
2
High
In parallel

48. How is ACR tubing sized?
Outside diameter (OD)
In parallel
20 A
20 degrees F

49. The fan switch opens at what temperature?
105 degrees F
With a minimum of three evenly spaced self-tapping screws
40 degrees F
Duct - electrical - and mechanical

50. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
45 degrees F
In series
40 degrees F
200