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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 do you calculate cfm?

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2. What are the components of a hard-start kit?
Before the vent
Duct - electrical - and mechanical
Potential relay and start capacitor
Shorted winding - open winding - and grounded winding

3. 8' round duct has a ballpark cfm of what?
It also rises
Negative
200
Over 800 degrees F

4. Why are some ACR tubing lines insulated?
Compressor
20 degrees above ambient
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
18 gauge

5. In what state is the refrigerant in the compressor?
Boil the liquid refrigerant out ot the oil within the crankcase
Vapor
Standard
SEER includes the energy used in the start-up and shut-down cycles

6. What is the typical pressure differance across a TXV?
A diffuser
Duct with insulation on the inside
100 psig
100

7. Do you need a trap on a push-through evaporator?
In series
Slugging
No
4

8. Where do you check the amps on a motor?
30 degrees F
On the common terminal
400
100 psig

9. The furnace size is calculated by what?
A piston type metering device
Heat loss
Nitrogen with a small amount of refrigerant
RLA/FLA x 5

10. How many cfm per ton?
400
Subtract ambient temperature from 100
1/4'
45 degrees F

11. How long should you leave a system off once you kill power before restarting it?
100
2 minutes
Yes
Pistons

12. What is a package unit?
ACR (air-conditioning refrigeration) tubing
The suction line or the low-pressure side
Btu/hr (output) / wattage (input)
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.

13. If the rpm's are 750 - how many poles does the motor have?
A diffuser
8
Pistons
100

14. What are normal conditions - as defined by the ARI.
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
15% silphos
Pi x radius squared
They are larger

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

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16. How do you calculate the area of a circle?
When the system is under pressure
Pi x radius squared
Nominal-sized tubing
Negative

17. 6' round duct has a ballpark cfm of what?
100
8-12 degrees F
Slugging
SEER includes the energy used in the start-up and shut-down cycles

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

19. How much superheat do you need to prevent liquid refrigerant from entering the compressor?
Infiltration and ventilation
Any amount
Yes
When it is a pull-through evaporator

20. What kind of refrigeratnts must be added in liquid form?
Negative
Blended refrigerants
RLA/FLA x 5
150

21. How are the condenser coils different on a high-efficiency unit?
40 degrees F
They are larger
It will be low
6

22. What component changes refrigerant from a low pressure gas to a high pressure gas?
Average feet per minute X area in square feet (H' x W'/144)
Compressor
300
On the common terminal

23. How many BTU's per ton?
A bypass duct or a dump zone
12000
Fiberglass
Below 800 degrees F

24. What is the typical pressure differance across a TXV?
100 psig
30 A
A swaging tool
It will be high

25. Do you need a trap on a pull-through evaporator?
Shorted winding - open winding - and grounded winding
Yes
Latent and sensible
The suction line or the low-pressure side

26. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
Dehydrated with caps on each end
Rise
45-55%
30 A

27. Sections of duct board can be fastened together with what?
1/4'
It will have a decrease in superheat
Staples and tape
In parallel

28. How will too much refrigerant effect superheat?
Before the vent
It will be low
Belt drive and direct drive
When the system is under pressure

29. Do you need a vent on a push-through evaporator?
12000
Standard
Yes
30 degrees F

30. How is nominal-sized tubing sized?
Positive
A diffuser
15% silphos
Inside diameter (ID)

31. In what length rolls is soft copper tubing normally available?
A bypass duct or a dump zone
25-ft or 50-ft
Fiberglass
Subtract ambient temperature from 100

32. What do you do after you braze a system?
100
Indoor fan motor - outdoor fan motor - and the compressor
Heat loss
Pull a vacuum

33. What sort of pressure will a pull-through evaporator have?
Negative
ACR (air-conditioning refrigeration) tubing
Pistons
140 degrees F

34. What sort of pressure will a pull-through evaporator have?
105 degrees F
100 psig
Infiltration and ventilation
Negative

35. What gauge is thermostat wire?
8
18 gauge
A band 4 inches or more in width
20 degrees above ambient

36. What distributes supply air to a room in a structure?
A diffuser
Subtract ambient temperature from 100
In parallel
1/4'

37. Multiple-zone systems often use what to alleviate the problem of excess air when only some zones are calling for conditioning?
1/4'
8-12 degrees F
2 minutes
A bypass duct or a dump zone

38. What are the two basic duct connection configurations for package units supply and return air ducts?
Over/under and side by side
100 psig
A dirty evaporator
Any amount

39. How do you calculate EER?
The suction line or the low-pressure side
Btu/hr (output) / wattage (input)
Positive
On the common terminal

40. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
Nitrogen with a small amount of refrigerant
30 degrees F
It will be low
True

41. The load on the evaporater will effect which pressure?
Duct with insulation on the inside
To remove humidity and lower dry bulb temperature
Suction
Yes

42. When do you install an auxillary drain pan?
Heat load
When it is above a conditioned space
Blended refrigerants
Compressor

43. The compressor is cooled by liquid refrigerant. (True of False)
Pistons
Standard
False
5 degrees

44. Can refrigerant line sets be altered in length?
40 degrees F
Duct - electrical - and mechanical
ACR (air-conditioning refrigeration) tubing
Yes

45. What is the typical temperature difference between a high-efficiency condenser and the ambient temperature?
20 degrees F
RLA/FLA x 5
Pi x radius squared
Yes

46. What tool is used to expand the diameter of soft copper tubing
They are physically larger
A swaging tool
20 degrees F
2

47. What sort of pressure will a push-through evaporator have?
20 degrees above ambient
Positive
When it is a pull-through evaporator
Yes

48. What is the typical temperature difference between a standard-efficiency condenser and the ambient temperature?
140 degrees F
Nitrogen with a small amount of refrigerant
30 degrees F
When it is above a conditioned space

49. How is flexible duct supported?
True
Over/under and side by side
45-55%
A band 4 inches or more in width

50. The fan switch opens at what temperature?
100 psig
6
105 degrees F
Pistons