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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 are the two functions of the air-conditioning system?
Inches of water column (in. WC)
To remove humidity and lower dry bulb temperature
On the common terminal
300

2. In what state is the refrigerant in the compressor?
Vapor
Standard
45-55%
Before the vent

3. What is a package unit?
Indoor fan motor - outdoor fan motor - and the compressor
40 degrees F
Slugging
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.

4. The furnace size is calculated by what?
Heat loss
High
A diffuser
25-ft or 50-ft

5. What are the three pressures created by moving air in ductwork?
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
Static pressure - velocity pressure - and total pressure
Inside diameter (ID)
2

6. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
With 4' saddles
Yes
A band 4 inches or more in width
It will have a decrease in superheat

7. The fan switch closes at what temperature?
140 degrees F
Over/under and side by side
Below 800 degrees F
S-clips and drives (cleats)

8. How is flexible duct supported?
40 A
Potential relay and start capacitor
A band 4 inches or more in width
40 degrees F

9. How many cfm per ton?
40 degrees F
400
2 minutes
SEER includes the energy used in the start-up and shut-down cycles

10. The crankcase heater on an air-conditioning compressor is used to what?
Boil the liquid refrigerant out ot the oil within the crankcase
The takeoff fitting
To remove humidity and lower dry bulb temperature
1/4'

11. How are round ducts supported?

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12. How do you calculate the area of a circle?
In series
A bypass duct or a dump zone
Pi x radius squared
On the common terminal

13. The refrigerant within the evaporator will typically boil at what temperature when it is 75 degrees inside with a relative humidity of 50%?
Dehydrated with caps on each end
True
40 degrees F
Pistons

14. How will too much refrigerant effect superheat?
It will be low
1/4'
30-35 degrees above ambient
True

15. What percentage silver do you need to use for an are-410 system?
Duct with insulation on the inside
Blended refrigerants
15% silphos
Over 800 degrees F

16. What kind of metering device do high-efficiency units usually use?
TXV
ACR (air-conditioning refrigeration) tubing
18 gauge
RLA/FLA x 5

17. Where do you install a trap on a drain line?
A swaging tool
It will be high
Inclined manometer
Before the vent

18. What do you do after you braze a system?
Yes
Pull a vacuum
They are physically larger
Duct - electrical - and mechanical

19. Do you need a trap on a push-through evaporator?
Heat loss
20 A
No
Pistons

20. The refrigerant within the evaporator will typically boil at what temperature when it is 75 degrees inside with a relative humidity of 50%?
In series
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
In parallel
40 degrees F

21. How are high-efficiency condenser coils different from standard-efficiency condenser coils?
They are physically larger
45-55%
2
Staples and tape

22. 10' round duct has a ballpark cfm of what?
ACR (air-conditioning refrigeration) tubing
Pi x radius squared
To lower the amount of pressure drop through the coil
400

23. Which is more efficient - a TXV or a fixed-orifice metering device?
TXV
It will have a decrease in superheat
True
Duct with insulation on the inside

24. How long should you leave a system off once you kill power before restarting it?
With a minimum of three evenly spaced self-tapping screws
2 minutes
2
4

25. 13 SEER is classified as what kind of efficiency?
High
A dirty evaporator
With 4' saddles
12000

26. If the rpm's are 1050 - how many poles does the motor have?
Belt drive and direct drive
Heat loss
6
Over/under and side by side

27. Which type of wire can handle a higher ampacity?
Side-by-side and over-and-under
A diffuser
Stranded
Below 800 degrees F

28. What is the name of the fitting where the branch line leaves the duct?
2 minutes
A band 4 inches or more in width
The takeoff fitting
Staples and tape

29. What is used to measure static air pressure in ducts.
2
Yes
Inclined manometer
S-clips and drives (cleats)

30. How many BTU's per ton?
Any amount
Staples and tape
12000
30 degrees F

31. What do you use to check for leaks?
5 degrees
8
25-ft or 50-ft
Nitrogen with a small amount of refrigerant

32. Which is more efficient - a TXV or a fixed-orifice metering device?
Pistons
On the common terminal
4
TXV

33. Why is it necessary to have multiple refrigerant circuits in some evaporator coils?
To lower the amount of pressure drop through the coil
105 degrees F
12000
When it is above a conditioned space

34. Sections of duct board can be fastened together with what?
Yes
Staples and tape
Rise
ACR (air-conditioning refrigeration) tubing

35. What are the three ways a motor can fail electrically?
S-clips and drives (cleats)
Rise
Shorted winding - open winding - and grounded winding
A swaging tool

36. How do you achieve high-efficiency?
By increasing the surface of the condenser coil
8-12 degrees F
They are larger
Fiberglass

37. If the rpm's are 3450 - how many poles does the motor have?
2
TXV
Inside diameter (ID)
Yes

38. A reciprocating compressor has what sort of moving parts?
Compressor
They are larger
Pistons
Sheet metal - galvanized sheet metal - fiberglass - and flexduct

39. How is the high pressure switch wired with the low pressure switch?
Subtract ambient temperature from 100
12000
In parallel
They are physically larger

40. What kind of copper tubing is used for refrigeration or air-conditioning applications?
ACR (air-conditioning refrigeration) tubing
TXV
Side-by-side and over-and-under
Indoor fan motor - outdoor fan motor - and the compressor

41. 6' round duct has a ballpark cfm of what?
With an are rating
30 A
100
TXV

42. What are the components of a hard-start kit?
Boil the liquid refrigerant out ot the oil within the crankcase
200
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Potential relay and start capacitor

43. Why are some ACR tubing lines insulated?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
20 degrees F
Yes
Before the vent

44. How many amps can 12 g wire handle?
High
L-type
20 A
True

45. Does a package unit come from the factory pre-charged?
By increasing the surface of the condenser coil
The takeoff fitting
Yes
200

46. If the rpm's are 1050 - how many poles does the motor have?
105 degrees F
By increasing the surface of the condenser coil
6
It will be high

47. How are round ducts connected to one another?
Before the vent
18 gauge
With a minimum of three evenly spaced self-tapping screws
In series

48. How do you calculate cfm?

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49. What are the two types of return air systems in residential installations?
20 A
Individual return air systems and central return air systems
25-ft or 50-ft
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity

50. If the rpm's are 750 - how many poles does the motor have?
8
100 psig
Standard
Shorted winding - open winding - and grounded winding