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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. Why are some ACR tubing lines insulated?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Belt drive and direct drive
No
TXV

2. Which is more efficient - a TXV or a fixed-orifice metering device?
TXV
Yes
20 A
Over/under and side by side

3. What sort of pressure will a pull-through evaporator have?
Negative
Vapor
Dehydrated with caps on each end
A band 4 inches or more in width

4. Why are some ACR tubing lines insulated?
Standard
Btu/hr (output) / wattage (input)
In series
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line

5. What kind of copper tubing is used for refrigeration or air-conditioning applications?
By increasing the surface of the condenser coil
ACR (air-conditioning refrigeration) tubing
A piston type metering device
It will be high

6. Do you need a trap on a push-through evaporator?
No
Inclined manometer
A band 4 inches or more in width
400

7. What kind of metering device do high-efficiency units usually use?
Blended refrigerants
TXV
It will have a decrease in superheat
It rises

8. The compressor is cooled by liquid refrigerant. (True of False)
A diffuser
A swaging tool
They are larger
False

9. Superheat should never be below how many degrees
S-clips and drives (cleats)
5 degrees
In series
20 A

10. How long should you leave a system off once you kill power before restarting it?
2 minutes
S-clips and drives (cleats)
Positive
True

11. What is the name of the fitting where the branch line leaves the duct?
Below 800 degrees F
The takeoff fitting
When it is a pull-through evaporator
18 gauge

12. How will too much refrigerant effect subcooling?
Individual return air systems and central return air systems
It will be high
Yes
Fiberglass

13. The fan switch closes at what temperature?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Inside diameter (ID)
To lower the amount of pressure drop through the coil
140 degrees F

14. What kind of metering device do high-efficiency units usually use?
TXV
Common
Static pressure - velocity pressure - and total pressure
L-type

15. How are the condenser coils different on a high-efficiency unit?
L-type
Individual return air systems and central return air systems
They are larger
12000

16. Most duct insulation is made of what?
They are physically larger
4
Fiberglass
With a minimum of three evenly spaced self-tapping screws

17. What do you use to check for leaks?
With 4' saddles
Individual return air systems and central return air systems
2
Nitrogen with a small amount of refrigerant

18. The crankcase heater on an air-conditioning compressor is used to what?
Boil the liquid refrigerant out ot the oil within the crankcase
Heat loss
Over/under and side by side
When the system is under pressure

19. When do you install a trap on a drain line?
S-clips and drives (cleats)
1/4'
Infiltration and ventilation
When it is a pull-through evaporator

20. In what length rolls is soft copper tubing normally available?
105 degrees F
30 A
2
25-ft or 50-ft

21. What are the two types of package units?
A band 4 inches or more in width
It will be low
It will be high
Side-by-side and over-and-under

22. What do you do after you braze a system?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Latent and sensible
On the common terminal
Pull a vacuum

23. On what terminal do you check amperage?
Shorted winding - open winding - and grounded winding
Common
Any amount
1/4'

24. How do you achieve high-efficiency?
By increasing the surface of the condenser coil
Before the vent
A diffuser
TXV

25. How will too much refrigerant effect superheat?
It will be low
To lower the amount of pressure drop through the coil
6
Outside diameter (OD)

26. How are high-efficiency condenser coils different from standard-efficiency condenser coils?
25-ft or 50-ft
Yes
Heat loss
They are physically larger

27. What do you do after you braze a system?
Negative
They are physically larger
Pull a vacuum
105 degrees F

28. What is the typical pressure differance across a TXV?
100 psig
140 degrees F
A swaging tool
Nominal-sized tubing

29. How is ACR tubing sized?
Shorted winding - open winding - and grounded winding
Fiberglass
Outside diameter (OD)
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.

30. How do you calculate EER?
Btu/hr (output) / wattage (input)
15 A
20 degrees F
Yes

31. How do you achieve high-efficiency?
By increasing the surface of the condenser coil
SEER includes the energy used in the start-up and shut-down cycles
45-55%
Potential relay and start capacitor

32. If pressure rises - what happens to the superheat?
Inclined manometer
15 A
30-35 degrees above ambient
It rises

33. If the rpm's are 1750 - how many poles does the motor have?
4
Pi x radius squared
Inclined manometer
In parallel

34. How do you calculate ballpark superheat?
It will be low
Subtract ambient temperature from 100
Yes
Compressor

35. What component changes refrigerant from a low pressure gas to a high pressure gas?
Blended refrigerants
Compressor
Subtract ambient temperature from 100
105 degrees F

36. What tool is used to expand the diameter of soft copper tubing
Positive
A swaging tool
A bypass duct or a dump zone
When the system is under pressure

37. What are the three major power-consuming devices on an air-conditioning system?
Indoor fan motor - outdoor fan motor - and the compressor
40 degrees F
The takeoff fitting
Side-by-side and over-and-under

38. How do you calculate cfm?

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39. Do you need a vent on a push-through evaporator?
12000
Yes
It will be low
Pistons

40. If the suction pressure rises - what happens to the head pressure?
It also rises
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
5 degrees
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity

41. 6' round duct has a ballpark cfm of what?
Over/under and side by side
15% silphos
TXV
100

42. Sections of duct board can be fastened together with what?
Staples and tape
SEER includes the energy used in the start-up and shut-down cycles
L-type
Yes

43. What are the three ways a motor can fail electrically?
Pistons
Shorted winding - open winding - and grounded winding
2 minutes
150

44. What is it called when liquid refrigerant gets into the compressor?
Duct with insulation on the inside
15 A
Slugging
With 4' saddles

45. The evaporator is designed to remove what two types of heat?
Vapor
A diffuser
Latent and sensible
Duct with insulation on the inside

46. How are high-efficiency condenser coils different from standard-efficiency condenser coils?
30 degrees F
Inches of water column (in. WC)
They are physically larger
Dehydrated with caps on each end

47. How do you calculate LRA?
2 minutes
Individual return air systems and central return air systems
It rises
RLA/FLA x 5

48. When do you install an auxillary drain pan?
Nominal-sized tubing
400
When it is above a conditioned space
Inclined manometer

49. 8' round duct has a ballpark cfm of what?
200
To lower the amount of pressure drop through the coil
Inside diameter (ID)
45 degrees F

50. If the rpm's are 1750 - how many poles does the motor have?
Dehydrated with caps on each end
4
Over/under and side by side
On the common terminal