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 is it called when liquid refrigerant gets into the compressor?
A dirty evaporator
30 degrees F
TXV
Slugging

2. The fan switch closes at what temperature?
140 degrees F
Latent and sensible
15 A
Average feet per minute X area in square feet (H' x W'/144)

3. What is lined duct?
A swaging tool
Duct with insulation on the inside
Standard
20 A

4. When do you install a trap on a drain line?
A swaging tool
When it is a pull-through evaporator
Over/under and side by side
Inside diameter (ID)

5. How long should you leave a system off once you kill power before restarting it?
It will be high
Subtract ambient temperature from 100
2 minutes
Shorted winding - open winding - and grounded winding

6. The furnace size is calculated by what?
Heat loss
Positive
No
300

7. If the rpm's are 750 - how many poles does the motor have?
It rises
Outside diameter (OD)
Below 800 degrees F
8

8. If pressure rises - what happens to the superheat?
It rises
S-clips and drives (cleats)
20 degrees above ambient
TXV

9. The evaporator is designed to remove what two types of heat?
1/4'
Latent and sensible
Standard
With a minimum of three evenly spaced self-tapping screws

10. Pressure in ductwork is measured In what?
4
150
105 degrees F
Inches of water column (in. WC)

11. What tool is used to expand the diameter of soft copper tubing
It will be low
A swaging tool
The suction line or the low-pressure side
Standard

12. How do you achieve high-efficiency?
Compressor
The suction line or the low-pressure side
Pi x radius squared
By increasing the surface of the condenser coil

13. How will too much refrigerant effect superheat?
Compressor
It will be low
Individual return air systems and central return air systems
The suction line or the low-pressure side

14. How will too much refrigerant effect subcooling?
20 A
It will be high
They are physically larger
2

15. At what temperature will soft solder melt?
45 degrees F
2
Duct with insulation on the inside
Below 800 degrees F

16. How are round ducts supported?

17. How is ACR tubing sized?
Before the vent
A bypass duct or a dump zone
Outside diameter (OD)
20 degrees above ambient

18. How does ACR copper pipe come?
30 degrees F
Fiberglass
Dehydrated with caps on each end
Average feet per minute X area in square feet (H' x W'/144)

19. What are the three pressures created by moving air in ductwork?
Yes
A diffuser
300
Static pressure - velocity pressure - and total pressure

20. How many BTU's per ton?
The suction line or the low-pressure side
Slugging
To lower the amount of pressure drop through the coil
12000

21. How do you calculate the area of a circle?
30-35 degrees above ambient
Pi x radius squared
200
A piston type metering device

22. The A/C size is calculated by what?
20 degrees F
Heat load
They are physically larger
30 degrees F

23. 10' round duct has a ballpark cfm of what?
Negative
400
Vapor
Over/under and side by side

24. At what temperature will soft solder melt?
False
200
It will have a decrease in superheat
Below 800 degrees F

25. What is the typical pressure differance across a TXV?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Potential relay and start capacitor
On the common terminal
100 psig

26. What kind of copper tubing is used for refrigeration or air-conditioning applications?
RLA/FLA x 5
ACR (air-conditioning refrigeration) tubing
Any amount
Yes

27. What are the three ways a motor can fail electrically?
Staples and tape
Shorted winding - open winding - and grounded winding
12000
Pull a vacuum

28. The crankcase heater on an air-conditioning compressor is used to what?
A dirty evaporator
Boil the liquid refrigerant out ot the oil within the crankcase
When the system is under pressure
RLA/FLA x 5

29. How do you calculate LRA?
RLA/FLA x 5
TXV
105 degrees F
2

30. Do you need a vent on a pull-through evaporator?
Inches of water column (in. WC)
200
Yes
Dehydrated with caps on each end

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

32. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
With an are rating
Common
In series
SEER includes the energy used in the start-up and shut-down cycles

33. What standard weight copper tubing is most often used in the heating and air-conditioning industry?
L-type
ACR (air-conditioning refrigeration) tubing
High
Blended refrigerants

34. 9' round duct has a ballpark cfm of what?
Slugging
300
Inches of water column (in. WC)
It will be high

35. 10' round duct has a ballpark cfm of what?
ACR (air-conditioning refrigeration) tubing
8-12 degrees F
400
Heat load

36. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
Any amount
True
Before the vent
45 degrees F

37. The evaporator is designed to remove what two types of heat?
L-type
The takeoff fitting
Latent and sensible
No

38. What is a package unit?
It also rises
A bypass duct or a dump zone
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Positive

39. Will a dirty condenser cause a rise or fall in pressure?
A diffuser
Outside diameter (OD)
Rise
30 degrees F

40. Which is more efficient - a TXV or a fixed-orifice metering device?
2 minutes
Latent and sensible
140 degrees F
TXV

41. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
Fiberglass
In series
When the system is under pressure
SEER includes the energy used in the start-up and shut-down cycles

42. What is it called when liquid refrigerant gets into the compressor?
18 gauge
Vapor
15% silphos
Slugging

43. If the rpm's are 750 - how many poles does the motor have?
45 degrees F
8
Before the vent
1/4'

44. What percentage silver do you need to use for an are-410 system?
The takeoff fitting
15% silphos
RLA/FLA x 5
Rise

45. What are the two ways that fresh air enters a structure?
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
A diffuser
Dehydrated with caps on each end
Infiltration and ventilation

46. Do you need a trap on a pull-through evaporator?
When it is above a conditioned space
8
Yes
When it is above a conditioned space

47. What is the typical temperature difference between a standard-efficiency condenser and the ambient temperature?
Inches of water column (in. WC)
30 degrees F
Subtract ambient temperature from 100
Outside of the male fitting

48. If the rpm's are 1050 - how many poles does the motor have?
30 degrees F
Dehydrated with caps on each end
Positive
6

49. Where do you check the amps on a motor?
On the common terminal
40 degrees F
20 degrees above ambient
Inside diameter (ID)

50. What are the three crafts normally associated with an air-conditioned installation?
Duct - electrical - and mechanical
TXV
Nitrogen with a small amount of refrigerant
Stranded