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. Most duct insulation is made of what?
With an are rating
Outside of the male fitting
Fiberglass
400

2. 10' round duct has a ballpark cfm of what?
Pistons
The takeoff fitting
400
Suction

3. How do you achieve high-efficiency?
15% silphos
Boil the liquid refrigerant out ot the oil within the crankcase
20 degrees F
By increasing the surface of the condenser coil

4. The compressor is cooled by liquid refrigerant. (True of False)
False
L-type
Heat loss
Over 800 degrees F

5. A reciprocating compressor has what sort of moving parts?
ACR (air-conditioning refrigeration) tubing
Pull a vacuum
With a minimum of three evenly spaced self-tapping screws
Pistons

6. In what state is the refrigerant in the compressor?
Vapor
Belt drive and direct drive
Indoor fan motor - outdoor fan motor - and the compressor
A bypass duct or a dump zone

7. What do you do after you braze a system?
Negative
Pull a vacuum
8-12 degrees F
Subtract ambient temperature from 100

8. What type of air conditioning system must be charged using the superheat method?
Inside diameter (ID)
A piston type metering device
45-55%
ACR (air-conditioning refrigeration) tubing

9. What gauge is thermostat wire?
18 gauge
20 A
Standard
On the common terminal

10. What is it called when liquid refrigerant gets into the compressor?
Slugging
Yes
Average feet per minute X area in square feet (H' x W'/144)
8-12 degrees F

11. How do you calculate LRA?
RLA/FLA x 5
In parallel
30 degrees F
Static pressure - velocity pressure - and total pressure

12. What is the design boiling point for most evaporator coils in residential air conditioning?
12000
Any amount
40 degrees F
In series

13. What is considered normal operating conditions?
With a minimum of three evenly spaced self-tapping screws
By increasing the surface of the condenser coil
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Duct - electrical - and mechanical

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

15. What kind of copper tubing is used for refrigeration or air-conditioning applications?
ACR (air-conditioning refrigeration) tubing
Nitrogen with a small amount of refrigerant
45-55%
Standard

16. What is the typical temperature difference between a high-efficiency condenser and the ambient temperature?
20 degrees F
Inclined manometer
Staples and tape
It also rises

17. What are the three crafts normally associated with an air-conditioned installation?
Dehydrated with caps on each end
Duct - electrical - and mechanical
400
30-35 degrees above ambient

18. How long should you leave a system off once you kill power before restarting it?
When it is a pull-through evaporator
2 minutes
30 degrees F
30 A

19. What are the two types of package units?
Nominal-sized tubing
18 gauge
Over/under and side by side
Side-by-side and over-and-under

20. Do you need a vent on a push-through evaporator?
Duct with insulation on the inside
Yes
25-ft or 50-ft
2

21. The evaporator is designed to remove what two types of heat?
Inside diameter (ID)
2 minutes
L-type
Latent and sensible

22. What are the two types of blower drives?
25-ft or 50-ft
Common
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Belt drive and direct drive

23. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
4
Positive
In series
40 degrees F

24. Where is insulation used on copper tubing used for air-conditioning?
Staples and tape
40 A
The suction line or the low-pressure side
Individual return air systems and central return air systems

25. How do you calculate ballpark superheat?
A diffuser
When it is a pull-through evaporator
Potential relay and start capacitor
Subtract ambient temperature from 100

26. What are the two functions of the air-conditioning system?
They are larger
400
Heat loss
To remove humidity and lower dry bulb temperature

27. 10' round duct has a ballpark cfm of what?
400
Pi x radius squared
It will have a decrease in superheat
Vapor

28. How are high-efficiency condenser coils different from standard-efficiency condenser coils?
They are physically larger
8-12 degrees F
When the system is under pressure
Potential relay and start capacitor

29. The fan switch closes at what temperature?
140 degrees F
It will be low
150
Over 800 degrees F

30. 7' round duct has a ballpark cfm of what?
It rises
150
To lower the amount of pressure drop through the coil
Pistons

31. What are the two ways that fresh air enters a structure?
Dehydrated with caps on each end
Infiltration and ventilation
Positive
Blended refrigerants

32. What can cause a decrease in suction pressure on an air-conditioning system?
Pull a vacuum
5 degrees
ACR (air-conditioning refrigeration) tubing
A dirty evaporator

33. What sort of pressure will a push-through evaporator have?
Subtract ambient temperature from 100
Over 800 degrees F
Positive
High

34. How are the condenser coils different on a high-efficiency unit?
S-clips and drives (cleats)
300
Positive
They are larger

35. What is the design boiling point for most evaporator coils in residential air conditioning?
40 degrees F
TXV
RLA/FLA x 5
RLA/FLA x 5

36. Pressure in ductwork is measured In what?
Inches of water column (in. WC)
1/4'
The suction line or the low-pressure side
40 A

37. What standard weight copper tubing is most often used in the heating and air-conditioning industry?
Dehydrated with caps on each end
L-type
When the system is under pressure
Fiberglass

38. On what terminal do you check amperage?
Positive
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
By increasing the surface of the condenser coil
Common

39. How long should you leave a system off once you kill power before restarting it?
40 degrees F
300
2 minutes
On the common terminal

40. How many cfm per ton?
105 degrees F
It will have a decrease in superheat
400
To remove humidity and lower dry bulb temperature

41. 6' round duct has a ballpark cfm of what?
150
20 A
100
Subtract ambient temperature from 100

42. What percentage silver do you need to use for an are-410 system?
Outside of the male fitting
A piston type metering device
300
15% silphos

43. What kind of refrigeratnts must be added in liquid form?
25-ft or 50-ft
The takeoff fitting
Pull a vacuum
Blended refrigerants

44. When do you install a trap on a drain line?
When it is a pull-through evaporator
105 degrees F
ACR (air-conditioning refrigeration) tubing
It rises

45. The refrigerant within the evaporator will typically boil at what temperature when it is 75 degrees inside with a relative humidity of 50%?
Heat load
40 degrees F
Duct with insulation on the inside
20 degrees F

46. If the rpm's are 3450 - how many poles does the motor have?
Belt drive and direct drive
2
It rises
It will have a decrease in superheat

47. Does a package unit come from the factory pre-charged?
Yes
Individual return air systems and central return air systems
Duct with insulation on the inside
20 degrees above ambient

48. How are round ducts connected to one another?
With a minimum of three evenly spaced self-tapping screws
A piston type metering device
ACR (air-conditioning refrigeration) tubing
400

49. How is the high pressure switch wired with the low pressure switch?
In parallel
Before the vent
1/4'
45 degrees F

50. What is considered normal operating conditions?
Stranded
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
False
Blended refrigerants