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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. Where is insulation used on copper tubing used for air-conditioning?
By increasing the surface of the condenser coil
The suction line or the low-pressure side
Inside diameter (ID)
400

2. What percentage silver do you need to use for an are-410 system?
They are physically larger
15% silphos
Potential relay and start capacitor
Yes

3. What are the two types of blower drives?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Belt drive and direct drive
30 A
5 degrees

4. What is used to measure static air pressure in ducts.
Inclined manometer
Rise
When the system is under pressure
Outside diameter (OD)

5. 8' round duct has a ballpark cfm of what?
200
Nominal-sized tubing
Fiberglass
A swaging tool

6. The load on the evaporater will effect which pressure?
Over 800 degrees F
Outside of the male fitting
Suction
100

7. How do you calculate EER?
2 minutes
Btu/hr (output) / wattage (input)
It will be low
On the common terminal

8. In what state is the refrigerant in the compressor?
With an are rating
Vapor
Nitrogen with a small amount of refrigerant
L-type

9. How is insulation around a duct rated?
Heat loss
15% silphos
With an are rating
Inside diameter (ID)

10. 10 SEER is classified as what kind of efficiency?
Blended refrigerants
300
It rises
Standard

11. What is a package unit?
20 A
Suction
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Slugging

12. 6' round duct has a ballpark cfm of what?
100
2
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
20 degrees F

13. Can refrigerant line sets be altered in length?
300
Inclined manometer
Yes
400

14. How are round ducts connected to one another?
With an are rating
With a minimum of three evenly spaced self-tapping screws
Pistons
It rises

15. What is the design boiling point for most evaporator coils in residential air conditioning?
S-clips and drives (cleats)
12000
ACR (air-conditioning refrigeration) tubing
40 degrees F

16. If pressure rises - what happens to the superheat?
Outside diameter (OD)
Inside diameter (ID)
Yes
It rises

17. What are the two ways that fresh air enters a structure?
40 degrees F
Infiltration and ventilation
Duct with insulation on the inside
Pi x radius squared

18. Why are some ACR tubing lines insulated?
40 degrees F
High
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
To lower the amount of pressure drop through the coil

19. How is the high pressure switch wired with the low pressure switch?
To lower the amount of pressure drop through the coil
A band 4 inches or more in width
In parallel
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line

20. How do you calculate the area of a circle?
Pi x radius squared
Stranded
Staples and tape
Btu/hr (output) / wattage (input)

21. What is the typical temperature difference between a high-efficiency condenser and the ambient temperature?
It will be high
20 degrees F
45-55%
40 degrees F

22. How long should you leave a system off once you kill power before restarting it?
2 minutes
They are larger
100 psig
Latent and sensible

23. Multiple-zone systems often use what to alleviate the problem of excess air when only some zones are calling for conditioning?
SEER includes the energy used in the start-up and shut-down cycles
When it is a pull-through evaporator
A bypass duct or a dump zone
8-12 degrees F

24. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
To remove humidity and lower dry bulb temperature
20 degrees above ambient
It also rises
It will have a decrease in superheat

25. When do you install a trap on a drain line?
Btu/hr (output) / wattage (input)
A diffuser
When it is a pull-through evaporator
30 A

26. What is the design boiling point for most evaporator coils in residential air conditioning?
Nitrogen with a small amount of refrigerant
40 degrees F
Btu/hr (output) / wattage (input)
Over/under and side by side

27. The furnace size is calculated by what?
200
45 degrees F
A bypass duct or a dump zone
Heat loss

28. How do you calculate LRA?
It also rises
Yes
High
RLA/FLA x 5

29. What standard weight copper tubing is most often used in the heating and air-conditioning industry?
High
L-type
They are physically larger
Inches of water column (in. WC)

30. How much superheat do you need to prevent liquid refrigerant from entering the compressor?
By increasing the surface of the condenser coil
Any amount
105 degrees F
Dehydrated with caps on each end

31. What are the two types of return air systems in residential installations?
Inclined manometer
Negative
20 degrees above ambient
Individual return air systems and central return air systems

32. How many BTU's per ton?
The suction line or the low-pressure side
12000
Individual return air systems and central return air systems
By increasing the surface of the condenser coil

33. How many amps can 14 g wire handle?
15 A
The suction line or the low-pressure side
Nitrogen with a small amount of refrigerant
2

34. How many amps can 14 g wire handle?
1/4'
With 4' saddles
15 A
High

35. What do you do after you braze a system?
Pull a vacuum
TXV
Nitrogen with a small amount of refrigerant
When it is above a conditioned space

36. In what length rolls is soft copper tubing normally available?
25-ft or 50-ft
Blended refrigerants
12000
Dehydrated with caps on each end

37. Where do you apply flux when soldering?
Outside of the male fitting
105 degrees F
Dehydrated with caps on each end
When the system is under pressure

38. What sort of pressure will a push-through evaporator have?
A band 4 inches or more in width
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Static pressure - velocity pressure - and total pressure
Positive

39. If the suction pressure rises - what happens to the head pressure?
Heat loss
20 degrees above ambient
It also rises
6

40. The compressor is cooled by liquid refrigerant. (True of False)
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
20 A
In series
False

41. Does a package unit come from the factory pre-charged?
Yes
Outside of the male fitting
12000
20 A

42. Where do you apply flux when soldering?
Nitrogen with a small amount of refrigerant
Nominal-sized tubing
Outside of the male fitting
Over/under and side by side

43. What gauge is thermostat wire?
18 gauge
Outside diameter (OD)
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Over 800 degrees F

44. What is the range for normal superheat and subcooling?
8-12 degrees F
Static pressure - velocity pressure - and total pressure
With a minimum of three evenly spaced self-tapping screws
18 gauge

45. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
25-ft or 50-ft
It will have a decrease in superheat
15 A
Subtract ambient temperature from 100

46. Where do you check the amps on a motor?
L-type
In series
To lower the amount of pressure drop through the coil
On the common terminal

47. Do you need a vent on a pull-through evaporator?
Yes
5 degrees
30 degrees F
Btu/hr (output) / wattage (input)

48. How many amps can 10 g wire handle?
Nominal-sized tubing
Pi x radius squared
2
30 A

49. How long should you leave a system off once you kill power before restarting it?
When the system is under pressure
Inclined manometer
True
2 minutes

50. If the rpm's are 1050 - how many poles does the motor have?
400
A piston type metering device
40 degrees F
6