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 do you calculate LRA?
30 degrees F
Individual return air systems and central return air systems
RLA/FLA x 5
It also rises

2. How is nominal-sized tubing sized?
Dehydrated with caps on each end
Inside diameter (ID)
High
150

3. Does a package unit come from the factory pre-charged?
When it is above a conditioned space
Yes
Nitrogen with a small amount of refrigerant
4

4. If the rpm's are 1050 - how many poles does the motor have?
With 4' saddles
High
A band 4 inches or more in width
6

5. Sections of duct board can be fastened together with what?
False
1/4'
2 minutes
Staples and tape

6. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
20 degrees F
Vapor
True
Vapor

7. What sort of pressure will a push-through evaporator have?
Suction
Positive
When the system is under pressure
Slugging

8. A reciprocating compressor has what sort of moving parts?
Common
Pistons
With an are rating
Inches of water column (in. WC)

9. How are high-efficiency condenser coils different from standard-efficiency condenser coils?
140 degrees F
True
18 gauge
They are physically larger

10. Superheat should never be below how many degrees
5 degrees
It will be low
Any amount
400

11. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Pull a vacuum
45-55%
Compressor

12. How do you calculate ballpark superheat?
1/4'
Nitrogen with a small amount of refrigerant
It rises
Subtract ambient temperature from 100

13. What is the normal evaporator temperature?
Average feet per minute X area in square feet (H' x W'/144)
Over/under and side by side
RLA/FLA x 5
45 degrees F

14. At what temperature does refrigerant condense in a standard-efficiency unit?
30-35 degrees above ambient
TXV
200
To lower the amount of pressure drop through the coil

15. What distributes supply air to a room in a structure?
40 degrees F
When it is above a conditioned space
A diffuser
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line

16. 7' round duct has a ballpark cfm of what?
100 psig
150
Nominal-sized tubing
400

17. The evaporator is designed to remove what two types of heat?
A diffuser
Latent and sensible
Common
4

18. What do you use to connect square and rectangular ductboard together?
It will be low
S-clips and drives (cleats)
They are physically larger
SEER includes the energy used in the start-up and shut-down cycles

19. What distributes supply air to a room in a structure?
A diffuser
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Outside of the male fitting
40 degrees F

20. What are the two types of blower drives?
Boil the liquid refrigerant out ot the oil within the crankcase
Belt drive and direct drive
Latent and sensible
To remove humidity and lower dry bulb temperature

21. At what temperature does refrigerant condense in a high-efficiency unit?
30-35 degrees above ambient
20 degrees above ambient
L-type
A band 4 inches or more in width

22. How is ACR tubing sized?
High
When it is a pull-through evaporator
Outside diameter (OD)
No

23. What type of air conditioning system must be charged using the superheat method?
Yes
105 degrees F
A piston type metering device
20 A

24. What type of air conditioning system must be charged using the superheat method?
In series
A piston type metering device
False
100 psig

25. How are the condenser coils different on a high-efficiency unit?
Outside of the male fitting
They are larger
Compressor
2 minutes

26. A reciprocating compressor has what sort of moving parts?
Duct - electrical - and mechanical
Btu/hr (output) / wattage (input)
S-clips and drives (cleats)
Pistons

27. The fan switch closes at what temperature?
Positive
Heat loss
140 degrees F
Btu/hr (output) / wattage (input)

28. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
2 minutes
Duct - electrical - and mechanical
In series
Vapor

29. What are the two types of blower drives?
Over/under and side by side
When it is above a conditioned space
400
Belt drive and direct drive

30. What kind of metering device do high-efficiency units usually use?
TXV
A dirty evaporator
Nominal-sized tubing
It will be high

31. The A/C size is calculated by what?
Yes
Heat load
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
5 degrees

32. How is insulation around a duct rated?
With a minimum of three evenly spaced self-tapping screws
Heat load
Before the vent
With an are rating

33. What is the typical pressure differance across a TXV?
100 psig
Standard
30 A
To remove humidity and lower dry bulb temperature

34. What kind of copper tubing is used for refrigeration or air-conditioning applications?
Yes
Duct - electrical - and mechanical
ACR (air-conditioning refrigeration) tubing
Fiberglass

35. What component changes refrigerant from a low pressure gas to a high pressure gas?
TXV
Common
It will be high
Compressor

36. What do you use to check for leaks?
1/4'
A bypass duct or a dump zone
Nitrogen with a small amount of refrigerant
With 4' saddles

37. 10 SEER is classified as what kind of efficiency?
Standard
Negative
4
It will have a decrease in superheat

38. How does ACR copper pipe come?
40 degrees F
True
Subtract ambient temperature from 100
Dehydrated with caps on each end

39. The load on the evaporater will effect which pressure?
Inside diameter (ID)
Rise
Pistons
Suction

40. How is insulation around a duct rated?
8-12 degrees F
45 degrees F
With an are rating
Shorted winding - open winding - and grounded winding

41. In what length rolls is soft copper tubing normally available?
1/4'
Pistons
25-ft or 50-ft
4

42. If the rpm's are 750 - how many poles does the motor have?
ACR (air-conditioning refrigeration) tubing
Duct with insulation on the inside
Latent and sensible
8

43. What sort of pressure will a pull-through evaporator have?
100
With 4' saddles
Individual return air systems and central return air systems
Negative

44. What are the three pressures created by moving air in ductwork?
Static pressure - velocity pressure - and total pressure
Boil the liquid refrigerant out ot the oil within the crankcase
20 degrees F
It rises

45. Where do you apply flux when soldering?
Individual return air systems and central return air systems
Rise
To lower the amount of pressure drop through the coil
Outside of the male fitting

46. The crankcase heater on an air-conditioning compressor is used to what?
Duct - electrical - and mechanical
40 degrees F
Boil the liquid refrigerant out ot the oil within the crankcase
To remove humidity and lower dry bulb temperature

47. If pressure rises - what happens to the superheat?
Heat load
It rises
To remove humidity and lower dry bulb temperature
Heat load

48. How are high-efficiency condenser coils different from standard-efficiency condenser coils?
They are physically larger
Yes
Inside diameter (ID)
Outside of the male fitting

49. What tool is used to expand the diameter of soft copper tubing
A swaging tool
Outside of the male fitting
Over 800 degrees F
Any amount

50. How long should you leave a system off once you kill power before restarting it?
2 minutes
Slugging
A swaging tool
With a minimum of three evenly spaced self-tapping screws