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 sort of pressure will a pull-through evaporator have?
Dehydrated with caps on each end
Individual return air systems and central return air systems
Negative
40 degrees F

2. How do you calculate cfm?

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3. How long should you leave a system off once you kill power before restarting it?
2 minutes
With a minimum of three evenly spaced self-tapping screws
Heat loss
Compressor

4. What do you use to connect square and rectangular ductboard together?
Individual return air systems and central return air systems
Outside diameter (OD)
S-clips and drives (cleats)
Potential relay and start capacitor

5. When must a copper joint never be soldered or brazed?
A diffuser
When the system is under pressure
When it is above a conditioned space
The suction line or the low-pressure side

6. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
Yes
Suction
Over/under and side by side
True

7. Does a package unit come from the factory pre-charged?
Shorted winding - open winding - and grounded winding
Yes
100
20 A

8. How will too much refrigerant effect superheat?
Subtract ambient temperature from 100
It will be low
S-clips and drives (cleats)
Fiberglass

9. How many amps can 14 g wire handle?
15 A
2 minutes
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Pull a vacuum

10. Superheat should never be below how many degrees
5 degrees
They are physically larger
Shorted winding - open winding - and grounded winding
Yes

11. How are high-efficiency condenser coils different from standard-efficiency condenser coils?
Dehydrated with caps on each end
Compressor
They are physically larger
8

12. How is flexible duct supported?
100 psig
Outside of the male fitting
With a minimum of three evenly spaced self-tapping screws
A band 4 inches or more in width

13. What do you do after you braze a system?
Belt drive and direct drive
Pull a vacuum
15 A
25-ft or 50-ft

14. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
Common
It will have a decrease in superheat
When the system is under pressure
300

15. How many amps can 12 g wire handle?
A bypass duct or a dump zone
They are larger
20 A
Btu/hr (output) / wattage (input)

16. What are the three pressures created by moving air in ductwork?
Latent and sensible
Static pressure - velocity pressure - and total pressure
Duct - electrical - and mechanical
Pi x radius squared

17. Where do you install a trap on a drain line?
Before the vent
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
25-ft or 50-ft
400

18. How is nominal-sized tubing sized?
To lower the amount of pressure drop through the coil
Btu/hr (output) / wattage (input)
15% silphos
Inside diameter (ID)

19. How many BTU's per ton?
300
12000
Below 800 degrees F
30-35 degrees above ambient

20. What tool is used to expand the diameter of soft copper tubing
A swaging tool
40 A
A diffuser
It also rises

21. What is the typical pressure differance across a TXV?
30 degrees F
True
Boil the liquid refrigerant out ot the oil within the crankcase
100 psig

22. At what temperature will soft solder melt?
Rise
L-type
Below 800 degrees F
Yes

23. How do you calculate ballpark superheat?
In parallel
2
Common
Subtract ambient temperature from 100

24. What kind of copper tubing is used for refrigeration or air-conditioning applications?
To remove humidity and lower dry bulb temperature
45-55%
Below 800 degrees F
ACR (air-conditioning refrigeration) tubing

25. Multiple-zone systems often use what to alleviate the problem of excess air when only some zones are calling for conditioning?
Pi x radius squared
200
Common
A bypass duct or a dump zone

26. Where do you check the amps on a motor?
Yes
Dehydrated with caps on each end
1/4'
On the common terminal

27. What kind of metering device do high-efficiency units usually use?
Staples and tape
Latent and sensible
Suction
TXV

28. The evaporator is designed to remove what two types of heat?
Over 800 degrees F
100
Latent and sensible
140 degrees F

29. Do you need a trap on a pull-through evaporator?
30 A
Yes
S-clips and drives (cleats)
With a minimum of three evenly spaced self-tapping screws

30. What is the name of the fitting where the branch line leaves the duct?
The takeoff fitting
40 degrees F
400
Common

31. How are the condenser coils different on a high-efficiency unit?
4
Btu/hr (output) / wattage (input)
They are larger
A band 4 inches or more in width

32. If the suction pressure rises - what happens to the head pressure?
Potential relay and start capacitor
1/4'
It also rises
8

33. What is a package unit?
TXV
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Outside of the male fitting
Static pressure - velocity pressure - and total pressure

34. What are the two functions of the air-conditioning system?
8
To remove humidity and lower dry bulb temperature
Duct with insulation on the inside
With an are rating

35. What is a package unit?
Potential relay and start capacitor
2
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Any amount

36. What do you use to connect square and rectangular ductboard together?
S-clips and drives (cleats)
Yes
Standard
Duct with insulation on the inside

37. What are the two types of package units?
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Over 800 degrees F
RLA/FLA x 5
Side-by-side and over-and-under

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

39. Why are some ACR tubing lines insulated?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Individual return air systems and central return air systems
Over/under and side by side
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line

40. Pressure in ductwork is measured In what?
Inches of water column (in. WC)
Yes
5 degrees
Yes

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

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42. Do you need a vent on a push-through evaporator?
15% silphos
Heat loss
Yes
45-55%

43. If the suction pressure rises - what happens to the head pressure?
It also rises
Suction
In series
With a minimum of three evenly spaced self-tapping screws

44. What is the name of the fitting where the branch line leaves the duct?
Btu/hr (output) / wattage (input)
1/4'
12000
The takeoff fitting

45. Do you need a vent on a push-through evaporator?
Yes
Nominal-sized tubing
Inches of water column (in. WC)
45 degrees F

46. Do you need a vent on a pull-through evaporator?
40 degrees F
True
15% silphos
Yes

47. What is considered normal operating conditions?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Yes
The takeoff fitting
A band 4 inches or more in width

48. The crankcase heater on an air-conditioning compressor is used to what?
Boil the liquid refrigerant out ot the oil within the crankcase
When it is a pull-through evaporator
To remove humidity and lower dry bulb temperature
With 4' saddles

49. What are the two ways that fresh air enters a structure?
Positive
Infiltration and ventilation
Yes
It will be low

50. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
Potential relay and start capacitor
Pull a vacuum
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
45-55%