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. On what terminal do you check amperage?
Indoor fan motor - outdoor fan motor - and the compressor
5 degrees
200
Common

2. 10' round duct has a ballpark cfm of what?
400
Suction
On the common terminal
6

3. Why are some ACR tubing lines insulated?
Heat loss
Below 800 degrees F
100
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line

4. At what temperature will brazing melt?
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
Over 800 degrees F
With 4' saddles
Slugging

5. What is the typical temperature difference between a standard-efficiency condenser and the ambient temperature?
30 degrees F
It also rises
105 degrees F
Indoor fan motor - outdoor fan motor - and the compressor

6. The load on the evaporater will effect which pressure?
2
Positive
Pull a vacuum
Suction

7. The crankcase heater on an air-conditioning compressor is used to what?
Nominal-sized tubing
Boil the liquid refrigerant out ot the oil within the crankcase
Individual return air systems and central return air systems
When it is a pull-through evaporator

8. How do you calculate the area of a circle?
Infiltration and ventilation
20 degrees above ambient
Slugging
Pi x radius squared

9. Most duct insulation is made of what?
RLA/FLA x 5
100
Fiberglass
Over 800 degrees F

10. What are normal conditions - as defined by the ARI.
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Nitrogen with a small amount of refrigerant
45 degrees F
Pull a vacuum

11. Does a package unit come from the factory pre-charged?
Inches of water column (in. WC)
300
In series
Yes

12. What are the two types of blower drives?
Belt drive and direct drive
A dirty evaporator
18 gauge
Blended refrigerants

13. How many cfm per ton?
400
Infiltration and ventilation
The takeoff fitting
Staples and tape

14. In what state is the refrigerant in the compressor?
They are physically larger
Any amount
15% silphos
Vapor

15. What can cause a decrease in suction pressure on an air-conditioning system?
Yes
Inside diameter (ID)
A dirty evaporator
Inclined manometer

16. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
S-clips and drives (cleats)
In series
A piston type metering device
Fiberglass

17. How many amps can 10 g wire handle?
It also rises
30-35 degrees above ambient
They are larger
30 A

18. At what temperature will soft solder melt?
Below 800 degrees F
Static pressure - velocity pressure - and total pressure
It also rises
Duct with insulation on the inside

19. Which is more efficient - a TXV or a fixed-orifice metering device?
TXV
To lower the amount of pressure drop through the coil
Infiltration and ventilation
A diffuser

20. Why is it necessary to have multiple refrigerant circuits in some evaporator coils?
On the common terminal
To lower the amount of pressure drop through the coil
A bypass duct or a dump zone
Yes

21. What are the two ways that fresh air enters a structure?
Infiltration and ventilation
Duct - electrical - and mechanical
Heat load
Pistons

22. A reciprocating compressor has what sort of moving parts?
Shorted winding - open winding - and grounded winding
By increasing the surface of the condenser coil
When it is a pull-through evaporator
Pistons

23. What are the three pressures created by moving air in ductwork?
True
40 degrees F
Average feet per minute X area in square feet (H' x W'/144)
Static pressure - velocity pressure - and total pressure

24. The compressor is cooled by liquid refrigerant. (True of False)
Yes
1/4'
False
Fiberglass

25. Do you need a vent on a pull-through evaporator?
15% silphos
Indoor fan motor - outdoor fan motor - and the compressor
15% silphos
Yes

26. Where do you apply flux when soldering?
1/4'
Outside of the male fitting
With an are rating
No

27. The furnace size is calculated by what?
Heat loss
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
It will be high
1/4'

28. The refrigerant within the evaporator will typically boil at what temperature when it is 75 degrees inside with a relative humidity of 50%?
15 A
Outside of the male fitting
45-55%
40 degrees F

29. How many cfm per ton?
400
25-ft or 50-ft
TXV
Duct with insulation on the inside

30. The load on the evaporater will effect which pressure?
In parallel
Suction
40 A
Yes

31. What is lined duct?
Negative
Fiberglass
Duct with insulation on the inside
By increasing the surface of the condenser coil

32. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
L-type
Dehydrated with caps on each end
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
45-55%

33. 9' round duct has a ballpark cfm of what?
300
High
A piston type metering device
A diffuser

34. Sections of duct board can be fastened together with what?
30-35 degrees above ambient
By increasing the surface of the condenser coil
30 A
Staples and tape

35. How many amps can 14 g wire handle?
Below 800 degrees F
S-clips and drives (cleats)
Inches of water column (in. WC)
15 A

36. How do you calculate EER?
Btu/hr (output) / wattage (input)
A diffuser
When it is a pull-through evaporator
2

37. 10' round duct has a ballpark cfm of what?
Slugging
They are physically larger
Nominal-sized tubing
400

38. How many amps can 12 g wire handle?
Below 800 degrees F
15% silphos
Staples and tape
20 A

39. What standard weight copper tubing is most often used in the heating and air-conditioning industry?
High
L-type
5 degrees
Infiltration and ventilation

40. What is the design boiling point for most evaporator coils in residential air conditioning?
Outside diameter (OD)
Infiltration and ventilation
40 degrees F
Yes

41. How are round ducts connected to one another?
With a minimum of three evenly spaced self-tapping screws
45 degrees F
RLA/FLA x 5
In series

42. Multiple-zone systems often use what to alleviate the problem of excess air when only some zones are calling for conditioning?
Belt drive and direct drive
Shorted winding - open winding - and grounded winding
A bypass duct or a dump zone
Suction

43. If the suction pressure rises - what happens to the head pressure?
150
Duct - electrical - and mechanical
It also rises
Heat load

44. Do you need a vent on a pull-through evaporator?
Outside of the male fitting
Yes
18 gauge
It will be low

45. The fan switch closes at what temperature?
A piston type metering device
140 degrees F
Dehydrated with caps on each end
20 degrees above ambient

46. 8' round duct has a ballpark cfm of what?
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
Over 800 degrees F
200
Btu/hr (output) / wattage (input)

47. What are the two types of package units?
400
Side-by-side and over-and-under
400
When it is a pull-through evaporator

48. How much superheat do you need to prevent liquid refrigerant from entering the compressor?
Any amount
200
It will be high
Pull a vacuum

49. Which type of wire can handle a higher ampacity?
In parallel
Stranded
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
It will be low

50. What do you do after you braze a system?
Pull a vacuum
With an are rating
15 A
Static pressure - velocity pressure - and total pressure