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. What kind of copper tubing is used for refrigeration or air-conditioning applications?
ACR (air-conditioning refrigeration) tubing
400
100 psig
400

2. How many BTU's per ton?
Heat loss
12000
Nitrogen with a small amount of refrigerant
Rise

3. What do you use to connect square and rectangular ductboard together?
Duct with insulation on the inside
S-clips and drives (cleats)
18 gauge
True

4. At what temperature will soft solder melt?
The takeoff fitting
300
Before the vent
Below 800 degrees F

5. How do you calculate the area of a circle?
A bypass duct or a dump zone
Positive
Pi x radius squared
Vapor

6. The furnace size is calculated by what?
Pull a vacuum
TXV
Heat loss
Pi x radius squared

7. How long should you leave a system off once you kill power before restarting it?
RLA/FLA x 5
Yes
200
2 minutes

8. Where do you apply flux when soldering?
Nitrogen with a small amount of refrigerant
Outside of the male fitting
On the common terminal
200

9. How will too much refrigerant effect subcooling?
300
Potential relay and start capacitor
It will be high
8-12 degrees F

10. At what temperature does refrigerant condense in a standard-efficiency unit?
Yes
5 degrees
8
30-35 degrees above ambient

11. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
20 degrees above ambient
45-55%
No
140 degrees F

12. How is the high pressure switch wired with the low pressure switch?
They are physically larger
Nitrogen with a small amount of refrigerant
A diffuser
In parallel

13. How do you calculate the area of a circle?
Yes
Slugging
Pi x radius squared
On the common terminal

14. Do you need a vent on a push-through evaporator?
200
Yes
It also rises
Blended refrigerants

15. How many amps can 10 g wire handle?
30 A
When the system is under pressure
When it is above a conditioned space
TXV

16. What are the two basic duct connection configurations for package units supply and return air ducts?
2
Over/under and side by side
With a minimum of three evenly spaced self-tapping screws
Vapor

17. Which is more efficient - a TXV or a fixed-orifice metering device?
TXV
The takeoff fitting
Nitrogen with a small amount of refrigerant
40 degrees F

18. What are the two basic duct connection configurations for package units supply and return air ducts?
Duct with insulation on the inside
To lower the amount of pressure drop through the coil
Over/under and side by side
Rise

19. If pressure rises - what happens to the superheat?
2
When it is a pull-through evaporator
It rises
Fiberglass

20. How are round ducts connected to one another?
18 gauge
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
L-type
With a minimum of three evenly spaced self-tapping screws

21. In what state is the refrigerant in the compressor?
Positive
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Vapor
Inches of water column (in. WC)

22. How are high-efficiency condenser coils different from standard-efficiency condenser coils?
400
4
They are physically larger
Outside of the male fitting

23. How do you calculate cfm?

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24. Why are some ACR tubing lines insulated?
Subtract ambient temperature from 100
Yes
20 degrees above ambient
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line

25. On what terminal do you check amperage?
A swaging tool
40 A
Indoor fan motor - outdoor fan motor - and the compressor
Common

26. If the suction pressure rises - what happens to the head pressure?
20 degrees above ambient
It also rises
RLA/FLA x 5
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity

27. How are the condenser coils different on a high-efficiency unit?
They are larger
No
It rises
300

28. Pressure in ductwork is measured In what?
Static pressure - velocity pressure - and total pressure
Inches of water column (in. WC)
Outside of the male fitting
Belt drive and direct drive

29. Do you need a vent on a pull-through evaporator?
Vapor
Yes
Belt drive and direct drive
Average feet per minute X area in square feet (H' x W'/144)

30. What are the four materials used to make duct?
15 A
Pull a vacuum
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
When it is above a conditioned space

31. How do you calculate LRA?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
When it is a pull-through evaporator
RLA/FLA x 5

32. What can cause a decrease in suction pressure on an air-conditioning system?
On the common terminal
A dirty evaporator
Shorted winding - open winding - and grounded winding
8-12 degrees F

33. What are the three ways a motor can fail electrically?
Shorted winding - open winding - and grounded winding
Static pressure - velocity pressure - and total pressure
Yes
Inches of water column (in. WC)

34. At what temperature does refrigerant condense in a high-efficiency unit?
20 degrees above ambient
Blended refrigerants
To lower the amount of pressure drop through the coil
Slugging

35. What percentage silver do you need to use for an are-410 system?
15% silphos
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Yes
Average feet per minute X area in square feet (H' x W'/144)

36. What is the design boiling point for most evaporator coils in residential air conditioning?
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Yes
Nitrogen with a small amount of refrigerant
40 degrees F

37. Can refrigerant line sets be altered in length?
The suction line or the low-pressure side
Potential relay and start capacitor
150
Yes

38. When do you install a trap on a drain line?
Yes
Belt drive and direct drive
100
When it is a pull-through evaporator

39. What do you use to check for leaks?
Yes
Duct - electrical - and mechanical
Nitrogen with a small amount of refrigerant
With an are rating

40. The A/C size is calculated by what?
Potential relay and start capacitor
40 degrees F
100 psig
Heat load

41. How many cfm per ton?
No
400
When it is a pull-through evaporator
Potential relay and start capacitor

42. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
2
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Latent and sensible
It will have a decrease in superheat

43. The load on the evaporater will effect which pressure?
Positive
Subtract ambient temperature from 100
Fiberglass
Suction

44. What is the typical temperature difference between a standard-efficiency condenser and the ambient temperature?
True
Yes
A bypass duct or a dump zone
30 degrees F

45. What tool is used to expand the diameter of soft copper tubing
Inside diameter (ID)
18 gauge
A swaging tool
Staples and tape

46. What do you use to connect square and rectangular ductboard together?
S-clips and drives (cleats)
When it is above a conditioned space
6
Average feet per minute X area in square feet (H' x W'/144)

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

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48. How much superheat do you need to prevent liquid refrigerant from entering the compressor?
Pi x radius squared
Inside diameter (ID)
Any amount
Yes

49. If the rpm's are 1050 - how many poles does the motor have?
6
Shorted winding - open winding - and grounded winding
Belt drive and direct drive
2

50. The compressor is cooled by liquid refrigerant. (True of False)
5 degrees
False
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
15 A