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. How much does a drain line need to drop per foot of length?

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2. How are round ducts supported?

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3. Which type of wire can handle a higher ampacity?
Stranded
Heat loss
Any amount
Standard

4. If the rpm's are 750 - how many poles does the motor have?
Boil the liquid refrigerant out ot the oil within the crankcase
Duct with insulation on the inside
8
4

5. When do you install an auxillary drain pan?
Duct with insulation on the inside
A piston type metering device
300
When it is above a conditioned space

6. The load on the evaporater will effect which pressure?
Suction
No
200
RLA/FLA x 5

7. How do you achieve high-efficiency?
It rises
By increasing the surface of the condenser coil
Infiltration and ventilation
To lower the amount of pressure drop through the coil

8. How is nominal-sized tubing sized?
Stranded
Inside diameter (ID)
Positive
Btu/hr (output) / wattage (input)

9. The furnace size is calculated by what?
Heat loss
15% silphos
Static pressure - velocity pressure - and total pressure
When it is above a conditioned space

10. How does ACR copper pipe come?
45-55%
Side-by-side and over-and-under
Dehydrated with caps on each end
When it is above a conditioned space

11. The fan switch closes at what temperature?
It will be low
140 degrees F
Duct - electrical - and mechanical
A piston type metering device

12. What are the two types of return air systems in residential installations?
Nominal-sized tubing
Individual return air systems and central return air systems
Infiltration and ventilation
Latent and sensible

13. What are normal conditions - as defined by the ARI.
Shorted winding - open winding - and grounded winding
15% silphos
To lower the amount of pressure drop through the coil
95 degrees F outside - 80 degrees F inside - and 50% relative humidity

14. When do you install a trap on a drain line?
It rises
When it is a pull-through evaporator
Over 800 degrees F
Dehydrated with caps on each end

15. What is the range for normal superheat and subcooling?
The suction line or the low-pressure side
150
20 A
8-12 degrees F

16. Which is more efficient - a TXV or a fixed-orifice metering device?
TXV
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Negative

17. The furnace size is calculated by what?
False
On the common terminal
Heat loss
Standard

18. How many amps can 10 g wire handle?
105 degrees F
30 A
300
6

19. The refrigerant within the evaporator will typically boil at what temperature when it is 75 degrees inside with a relative humidity of 50%?
15% silphos
The takeoff fitting
40 degrees F
Before the vent

20. How do you calculate EER?
Fiberglass
Potential relay and start capacitor
A swaging tool
Btu/hr (output) / wattage (input)

21. How is flexible duct supported?
Standard
1/4'
A band 4 inches or more in width
ACR (air-conditioning refrigeration) tubing

22. How is nominal-sized tubing sized?
Inside diameter (ID)
A band 4 inches or more in width
The suction line or the low-pressure side
Common

23. Where do you install a trap on a drain line?
Average feet per minute X area in square feet (H' x W'/144)
A piston type metering device
Before the vent
Yes

24. Will a dirty condenser cause a rise or fall in pressure?
Rise
Over/under and side by side
They are larger
A diffuser

25. The evaporator is designed to remove what two types of heat?
By increasing the surface of the condenser coil
In parallel
Stranded
Latent and sensible

26. How many BTU's per ton?
Belt drive and direct drive
High
12000
8

27. Why is it necessary to have multiple refrigerant circuits in some evaporator coils?
To lower the amount of pressure drop through the coil
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
True
Over/under and side by side

28. Do you need a vent on a pull-through evaporator?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
High
With 4' saddles
Yes

29. What is the typical temperature difference between a high-efficiency condenser and the ambient temperature?
20 A
Belt drive and direct drive
With 4' saddles
20 degrees F

30. What are the two types of blower drives?
25-ft or 50-ft
With 4' saddles
Belt drive and direct drive
Yes

31. How is ACR tubing sized?
Outside diameter (OD)
400
To remove humidity and lower dry bulb temperature
Pull a vacuum

32. What is the normal evaporator temperature?
45 degrees F
No
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
TXV

33. How is the high pressure switch wired with the low pressure switch?
150
25-ft or 50-ft
In parallel
Outside diameter (OD)

34. The A/C size is calculated by what?
Below 800 degrees F
Side-by-side and over-and-under
Heat load
With 4' saddles

35. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
It will have a decrease in superheat
Nominal-sized tubing
They are physically larger
High

36. At what temperature will brazing melt?
False
400
Over 800 degrees F
Over/under and side by side

37. Do you need a vent on a push-through evaporator?
25-ft or 50-ft
100
Yes
Inclined manometer

38. The fan switch opens at what temperature?
105 degrees F
Vapor
18 gauge
Below 800 degrees F

39. What sort of pressure will a push-through evaporator have?
20 degrees above ambient
Positive
Pistons
Fiberglass

40. In what state is the refrigerant in the compressor?
Pi x radius squared
Slugging
300
Vapor

41. What is lined duct?
Latent and sensible
Fiberglass
300
Duct with insulation on the inside

42. How many cfm per ton?
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Indoor fan motor - outdoor fan motor - and the compressor
400
100

43. 8' round duct has a ballpark cfm of what?
Dehydrated with caps on each end
200
A bypass duct or a dump zone
Pull a vacuum

44. The fan switch closes at what temperature?
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
140 degrees F
Slugging
Heat loss

45. What can cause a decrease in suction pressure on an air-conditioning system?
20 degrees above ambient
S-clips and drives (cleats)
A dirty evaporator
Pi x radius squared

46. What are the two functions of the air-conditioning system?
To remove humidity and lower dry bulb temperature
25-ft or 50-ft
Infiltration and ventilation
It rises

47. What are the three ways a motor can fail electrically?
Inclined manometer
Nominal-sized tubing
Shorted winding - open winding - and grounded winding
Nitrogen with a small amount of refrigerant

48. What is it called when liquid refrigerant gets into the compressor?
Slugging
15 A
High
Blended refrigerants

49. What is used to measure static air pressure in ducts.
Inclined manometer
Outside of the male fitting
Dehydrated with caps on each end
Positive

50. What are the three pressures created by moving air in ductwork?
A diffuser
Static pressure - velocity pressure - and total pressure
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
With an are rating